Larson Davis System 824 Technical Reference Manual Download Page 325 | Manualshive

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9/29/09

Performing a Sound Level Measurement

9-13

Linearity Range

When making a measurement, the upper and lower linearity
range limits of the instrument for the setting presently in
effect are indicated by the dark regions with light numbers
as indicated below.

Changing the range (ISM and LOG Modes) or gain (SSA
Mode will change these limits. For very low (high) level
measurements, it may be necessary to utilize a microphone
having a higher (lower) value of sensitivity in order to
perform a measurement within the linearity range of the
instrument.

Upper Limit of Linearity

Lower Limit of Linearity Range

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Summary of Contents for System 824

Page 1: ...Model 824 Precision Sound Level Meter Real Time Analyzer Reference Manual...

Page 2: ......

Page 3: ...I824 01 Rev P Technical Reference Manual Larson Davis Model 824...

Page 4: ...ld not be construed as a commitment or representation by PCB Piezotronics Inc This publication may contain inaccuracies or typographical errors PCB Piezotronics Inc will periodically update the materi...

Page 5: ...ng and Inspection 1 14 1 16 Comments concerning the Digital Signal Processor 1 16 Accessories and Optional Equipment 1 16 Connecting Internal or External Power 1 18 Using the NiMH Battery Pack 1 18 Us...

Page 6: ...ll 2 13 Storing Data 2 13 Recalling Data 2 13 Calibration 2 14 Correction of Calibrator Output Level 2 17 Chapter 3 Front Panel Keys Functions and Menus 3 1 v Power Key 3 3 Power up the Instrument Vie...

Page 7: ...during a Measurement 4 8 Recalling Stored Data 4 11 Selecting and Modifying Instrument Definitions IDs 4 12 The Setup Menu 4 13 The Active ID 4 13 Menu Scrolling 4 15 Permanent IDs 4 15 Write protecte...

Page 8: ...urrent Overall SLM Display d Peaks 5 29 Current Overall SLM Display e TWA 5 30 Exposure Views 5 31 Exposure Display a 5 32 Exposure b Display 5 33 Exposure c Display 5 34 Ln Centiles Views 5 35 Ln a D...

Page 9: ...play 5 70 Wind c Percent Display 5 71 Chapter 6 System 824 Virtual Instruments 6 1 System 824 Virtual Instruments 6 1 Selecting an Instrument ID 6 3 Sound Spectrum Analyzer SSA 6 3 SSA Measuring Range...

Page 10: ...ISM 7 10 Control Settings _ SSA LOG 7 11 AC DC Output Settings SSA LOG ISM 7 12 Logic Input Setting SSA LOG ISM 7 12 Logic Output Setting SSA LOG ISM 7 13 Logic Output Time Setting SSA LOG ISM 7 15 L...

Page 11: ...30 LOG and SSA Time History Settings 7 30 Hist Enable LOG SSA 7 32 Hist Period LOG SSA 7 33 Period Units LOG SSA 7 33 Other Level LOG only 7 33 Resolution LOG SSA 7 34 Advanced Time History LOG SSA 7...

Page 12: ...of Integrating SLM ISM Settings 7 50 Menu Layout of Logging SLM Settings 7 52 Advanced Menu Layout 7 56 Check Menus 7 59 Check Menu Example 7 60 SLM Check Menu Options SSA and LOG 7 62 Mark Display 7...

Page 13: ...asurement 9 1 Configuration of the System 9 1 Selecting a Measurement Mode 9 1 Selecting a Measurement ID 9 2 Editing the Microphone Parameters 9 3 Calibration 9 3 Entering the Noise Floor Values 9 4...

Page 14: ...Existing Setup 10 16 Locking and Unlocking Setups 10 17 Downloading Measurement Data 10 17 Specifying a Destination File 10 18 Changing the Download File Name 10 20 Adding Notes to a download file 10...

Page 15: ...35 Spatial Avg Views 11 35 Spatial Avg Check Menu 11 37 Avg History Check Menu 11 38 Rooms Views 11 39 Chapter 12 FFT Optional 12 1 Features 12 1 Settings Menu 12 1 Settings Descriptions 12 3 FFT Dis...

Page 16: ...Display 13 14 Manual Lock 13 16 Automatic Lock 13 16 Linearity FFT Check Menu 13 17 Flatness FFT Display 13 18 THD Display 13 19 THD Check Menu 13 21 Pulse FM Display 13 21 Pulse FM a Display 13 22 P...

Page 17: ...Records A 54 Types of History A 55 Advance A 55 Backup A 56 Find A 56 History Data Variables A 57 Exceedance History Variables A 57 Interval History Variables I Commands A 59 Daily History Variables D...

Page 18: ...i D 1 Average Sound Level Lavg D 2 Community Noise Equivalent Level CNEL Lden D 2 Criterion Duration Tc D 3 Criterion Sound Exposure CSE D 3 Criterion Sound Level Lc D 3 Daily Personal Noise Exposure...

Page 19: ...ectrum D 22 Threshold Sound Level Lt D 22 Time Weighted Average Sound Level TWA LTWA TC D 22 Time Weighting D 23 Vibration D 23 Wavelength l D 23 Wavenumber k D 23 Appendix E Memory Usage E 1 LOG Memo...

Page 20: ...Linear Operating Range F 5 Electrical Signal Input Device F 5 Inherent Noise F 5 Maximum Sound Pressure Level F 6 Power Supply Voltage Range F 6 Display Device F 6 Stabilization Time Following Changes...

Page 21: ...the contents of this user manual and the System 824 s features functions and measurement capabilities It also includes instructions on unpacking the System 824 Chapter 2 Overview Provides an overview...

Page 22: ...be optimal for the measurement conditions Chapter 10 Using the 824 Utility Software Describes how to connect the 824 to a computer in order to download translate and export data Chapter 11 RTA Option...

Page 23: ...monitoring where measurements are performed and stored automatically over a period of days or weeks Appendix F SLM Testing to IEC61672 1 Presents information for testing the sound level meter function...

Page 24: ...okmarks simply left click the tab once more Expanding Bookmarks For any entry if there is a within the rectangle to the left there are sub entries which can be displayed upon expanding the tree by cli...

Page 25: ...splayed previous to clicking on a bookmark text line right click on the display page then left click on Go to Previous View Links Click to Display Page The Table of Contents and the Index have a page...

Page 26: ...vides instructions for unpacking inspecting and initially assembling the System 824 Formatting This manual uses the following format conventions In step by step directions the process what you do is s...

Page 27: ...ter and real time spectrum analyzer optional LOG Logging SLM optional ISM Integrating SLM standard RTA Adds high speed spectral data gathering optional FFT Adds Fast Fourier Analysis to the 824 option...

Page 28: ...on feature requires the firmware option 824 WND not included with standard System 824 configurations Measurement of windspeed tacho and wind direction throttle position using external weather transduc...

Page 29: ...FT 400 line snapshots AC DC output unweighted with gain to 50 dB and attenuation to 20 dB Flash memory for in field firmware upgrades Multi tasking processor provides simultaneous measuring viewing tr...

Page 30: ...m 824 shown in Figure 1 1 includes the following 1 2 diameter condenser microphone Backlit graphic 64 x 128 pixel LCD display 14 key soft rubber backlit keypad AC DC output control serial and external...

Page 31: ...control information Figure 1 3 9 pin mini DIN control connector solder view 1 Ground 2 Logic output 0 to 5 volts active high through 1 k 3 Logic input 0 to 5 volts active high 100 k load 4 Wind speed...

Page 32: ...1 Flow control output RS 232C levels 2 Flow control input RS 232C levels 3 Transmit data negative output RS 232C levels 4 Ground 5 Receive data negative input RS 422 6 Transmit data positive output R...

Page 33: ...mplifier input connector accepts the PRM902 preamp System Diagram Figure 1 6 illustrates the acoustic to digital signal path in the System 824 As you can see incoming sound is first converted to an el...

Page 34: ...items listed below Retain the packaging for safe shipment for calibration service Report any damage or shortage immediately to Larson Davis Inc at 801 375 0177 If you have not already done so please r...

Page 35: ...Analog to Digital Converter External Power Battery Temperature Sensor Power Supply Control I O Microprocessor RAM 1 2 to 2 MB Flash ROM Real time clock and calendar Serial I O Key Pad Graphic Liquid C...

Page 36: ...ased with or without a microphone they all include the Model PRM902 microphone preamplifier The System 824 824L and 824A are delivered with the following standard accessories 824 ACC Pack Battery pack...

Page 37: ...ies when NiMH battery pack is not used 3 1 2 diameter windscreen WS001 The following optional equipment is also available CAL200 Sound Level Calibrator 1000 Hz 94 or 114 dB IEC 942 1988 Class 1 CAL250...

Page 38: ...ery cover at the back of the System 824 by hand or using a flat blade screwdriver If individual cell batteries were previously used remove the Terminal Assembly Figure 1 8 Insert the battery pack so t...

Page 39: ...eing used as follows Step 1 Press the v key Step 2 Press the c key Step 3 Use the dkey to highlight Type Step 4 Press ckey to activate the Battery Type menu Step 5 Press dor ukeys to select the approp...

Page 40: ...partment with alkaline batteries and Terminal Assembly installed Note location of Terminal Assembly Using the AC Power Adapter You may use an external power source via the external power connector usi...

Page 41: ...the existing list of instrument definitions The System 824 was designed to be upgraded with new instrument capabilities as they are made available Please contact Larson Davis for information on the la...

Page 42: ...ment period are displayed and can be stored for later recall In addition to a live spectrum display the System 824 can display an equivalent level Leq spectrum a minimum bin by bin level Lmin spectrum...

Page 43: ...ameters a feature we call Any Data Note The detector used to create Leq is a pure integrating true RMS detector which integrates the energy over a specific period of time It may be as short as 1 32 se...

Page 44: ...RTA SSA ID but it does not provide frequency spectrum measurement capability However since less digital processing is required the measurement linearity range is 105 dBA permitting the use of a single...

Page 45: ...e of the two alternative choices of frequency weighting Ln 6 values with 0 1 dB resolution based on user selected percentages with 0 01 resolution Date time and duration of interval Six user selected...

Page 46: ...of demo IDs Cannot print reports Cannot store data Cannot perform any I O commands Only 20 demos are permitted Memory must be purged prior to activating these IDs The following is an overview of how t...

Page 47: ...Measurement SLM RTA SSA Without getting into the fine details of operating the System 824 let s just press some keys and see what it can measure and display Step 1 Let s look at the SLM RTA SSA ID Acc...

Page 48: ...easurement press the p key a second time While paused thelandrkeys can be used to move a cursor across the time history and display the SPL and secondary parameters as measured at any particular time...

Page 49: ...onding to the Fast and Impulse detectors Go back to the Slow detector and press the check c key or wait several seconds until the highlight disappears Changing the frequency weighting of the displayed...

Page 50: ...nging the frequency weighting of the displayed Lpeak value Step 1 With the Peak label selected press the uor dkeys to highlight the Peak weighting Use therorlarrow keys to display the A C or Flat weig...

Page 51: ...nge up or down See page 5 3 Step 2 Use therorlarrow keys to change the input gain Views For each instrument type e g ISM LOG or SSA a unique set of data displays or VIEWS are available Selecting a VIE...

Page 52: ...und Level parameters measured and auto matically stored at regular user defined time intervals Leq Spec trum Leq spectra measured and automatically stored at the interval rate Max Min Spectra Instanta...

Page 53: ...ta can be stored to non volatile memory before the instrument is reset or the setup changed otherwise the data will be lost Attempting to change the setup while there is measured data available will c...

Page 54: ...ss the check c key again Calibration Power off the instrument prior to connecting a microphone or preamplifier the high voltage spike created when connecting while the instrument is on can damage sens...

Page 55: ...e so a corrected level should be used Similarly the sensitivity of the microphone itself is a function of temperature and static pressure For directions on compensating for temperature and static pres...

Page 56: ...and press c to activate the cal ibration Check process The display will show the measured level and the difference from the calibrator level entered and the measured level as shown Step 10 If the cal...

Page 57: ...are at a temperature other than near room temperature or static pressures not near sea level then corrections need to be added for the ambient temperature and the prevailing static pressure Check the...

Page 58: ...2 18 824 Reference Manual 9 29 09...

Page 59: ...contains an overview of the functions which are accessed through the System 824 keypad see Figure 3 1 below Figure 3 1 System 824 Keypad The 14 keys on the System 824 keypad are organized into these f...

Page 60: ...rase function R RESET Displays Reset options menu Current Overall Options u l d ARROW Used to move through System 824 menus change settings and scroll through data displays The lkey exits menu s c SEL...

Page 61: ...v key again will activate a PWR display where you can change screen contrast turn the backlight on or off and adjust power options To turn the instrument off press and hold down the v key until promp...

Page 62: ...y again will return you to the previous display From this display you can adjust the contrast and turn the backlight on or off Pressing the u or d key adjusts the contrast Pressing ther key turns the...

Page 63: ...matically go into a standby mode after a set amount of time display blanks and serial port turns off Automatically shut off the instrument after a set amount of time Conserve internal battery for memo...

Page 64: ...to force the 824 to shut off The charge mode will be activated automatically when external power is applied and the battery is at 75 capacity or less Whenever external power is applied the 824 will tr...

Page 65: ...System 824 powers down in the specified number of minutes of inactiv ity Standby Time 0 99 minutes Time in minutes when Standby Time power save is activated When activated the System 824 screen blanks...

Page 66: ...ower may cause loss of memory WARNING Turn off power to change the microphone or preamplifier Sensitive electronics can be damaged by voltage spikes s Run Stop Key Use the s RUN STOP key to toggle the...

Page 67: ...nt data buffers that can separately accumulate data In essence the instrument becomes two sound level meters in one The data in the primary buffer is referred to as the overall measurement while data...

Page 68: ...se key will not start a new measure ment but rather will simply pause the existing measurement for a moment After the desired pause period press the pause key p again to resume the measurement The fol...

Page 69: ...the next higher number or character value and use the d key to step to the next lower number or character value Pressing and holding an arrow key will repeat the actuation of the key The repeat rate...

Page 70: ...available data displays which are selected using this key When you press the V key a menu containing the available data displays will appear The fol lowing example is a View menu for the SSA instrumen...

Page 71: ...ing appears If no data files have been saved the Recall option will not be available for recall From this menu you can store data or view and recall stored data If the instrument is running when you t...

Page 72: ...ata file The data file also contains calibration information that may be different than the current calibration When Run is pressed the recalled calibration is replaced by the latest cur rent calibrat...

Page 73: ...or d keys to highlight the desired ID Press the c key to select and activate the it The Setup menu then closes and the main display appears The modification of a selected ID to meet the requirements...

Page 74: ...pable of holding up to 8 characters Name format cccccccc ccc The first 8 characters form the name and the last three are the extension that indicate the instrument type e g SSA The name does not have...

Page 75: ...the c key A locked symbol appears next to locked IDs in the Setup menu except for the current running ID and symbolizes that this ID is Write Protected Once the ID is write protected it cannot be cha...

Page 76: ...allows you to view system settings and other displays NOTE From any of the following dis plays the u and d arrow keys will step to the next or previous display in the list The Tools menu provides the...

Page 77: ...ll record status Power Monitor Display Power Status Power Settings Power Off Mode Auto Off Time Standby Time Backlight Time Backlight LCD Contrast External Power Min Battery Activate Battery Charger T...

Page 78: ...d Pressing the rkey moves to the About b screen The fol lowing appears The About b display shows the instrument s custom name and title fields printed on System 824 reports The fields are generally se...

Page 79: ...scribe your measurement Date Format Displays the date in Normal or ISO 8601 format Normal has the form of ddmmmyyyy and ISO 8601 has the form yyyymmmdd where dd is the two digit date of the month 1 to...

Page 80: ...ion information use the u or d key to select Calibration from the Tools menu then press the c key The following screen appears The Calibration display shows the date and time of the last calibration c...

Page 81: ...e or to view the timer settings use the u or d key to select Clock Timer from the Tools menu then press the c key The following appears The Time a or clock display shows the current time day of the we...

Page 82: ...onth shows as then the message Time not set will be shown when the Run key is pressed Current Time Date To set the current time and or date highlight the desired item i e Time or Date and then press t...

Page 83: ...u or d key to highlight the desired day then press the c key to select Timer Mode The timer is used when you want to have the 824 automatically turn on gather data and stop at pre deter mined date s...

Page 84: ...the instrument on and initiate one run stop cycle per day from the run date until the stop date 2 Day The timer will automatically turn the instrument on and initiate two run stop cycles per day The t...

Page 85: ...ime 2 These settings are used to spec ify a second measurement s beginning and ending time in the 2 day timer mode Memory To access the Memory display use the u or d key to select Memory from the Tool...

Page 86: ...setup registers allocated and the total amount of memory including that memory allocated for setup registers Memory Settings can also be accessed by pressing the c key from the Memory display screen...

Page 87: ...re upgrade follow these steps 1 Alter the permanent IDs as desired and save your customized setting using a name of your choice 2 Enter the unit Name and other system settings in the TOOLS About menu...

Page 88: ...is no problem deleting data from the last to the first Deleting the Last Stored Record Step 1 To delete the last stored record press the TOOLS T key to access the TOOLS menu The follow ing menu appear...

Page 89: ...idual records In essence this will UNDO the storing of a data file Open Choosing Open recalls the file into memory the File record is deleted and the data in memory marked as if it had never been stor...

Page 90: ...Step 3 Highlight Memory and press the rightrarrow key to access the Delete Last function Step 4 Highlight Delete Last and press the Check c key The records will appear one at a time Below are example...

Page 91: ...menu option allows adjustment of the auto power off the contrast or viewing angle turns the backlight on or off and adjusts settings that control the power conservation fea tures Refer to the section...

Page 92: ...on from the Tools menu then press ther key A menu similar to the following appears The printer has its own baud rate for printing reports and is not affected by this setting Baud Rate Speed at which t...

Page 93: ...t a network or serial address Flow Control Flow control of the serial connection Flow control can be changed to None Hardware Xoff or Both Flow control prevents the loss of data when either the instru...

Page 94: ...on an Exceedance or an Alarm or both Phone Number The 824 will dial the phone number entered here on the events selected in the dial out mode Monitor Number The monitor number is used to identify whic...

Page 95: ...rinting Reports on page 8 2 for more information on printing The P PRINT key displays the printing options menu These options enable printing of graphical and tabular data reports directly from the in...

Page 96: ...ter connection you can print a num ber of reports The Recall Format sub menu option is used to enable various reports Do this by highlighting the corre sponding menu item and pressing the c key Use Ta...

Page 97: ...ted settings properly configured you can easily take a measurement and examine the readings from the data collected Taking an actual measurement with the System 824 is as easy as pressing the s RUN ST...

Page 98: ...this key the Larson Davis logo appears while a number of tests are performed The fol lowing screen then appears for a few seconds Power off prior to changing microphone or preamplifier to avoid possib...

Page 99: ...qual to the output level of the calibrator to be used for the calibration typically 94 or 114 dB If the value indicated is not equal to this value use the d key to highlight the Cal Level menu Press t...

Page 100: ...be a forty second delay while the instrument stabilizes at the High range setting ll High Range Calibration Note When using a prepolarized microphone during setup Electret should have been selected as...

Page 101: ...used in the System 824 The following example explains how to record and store a measurement in the SLM mode of the SSA instrument If the 824 is already using the SSA ID there will be a to the left of...

Page 102: ...s the c key to select it The last used SLM RTA display appears Step 3 At this point if you want to view a display other than the one shown press the V VIEW key Use the u or d keys to highlight the des...

Page 103: ...first be stopped Step 6 To store the current measurement readings press the D Data key Select Store File and press the c key This will store the measurement s data Step 7 To turn off the instrument pr...

Page 104: ...instrument from the Setup menu and press RUN STOP s to begin tak ing a measurement as explained in the SLM RTA Measurements section found on page 4 3 Step 2 While the measurement is running press the...

Page 105: ...t corresponds to the SPL graphical display for that particular frequency Step 5 Press thedarrow key to change to the RTA Leq view A screen similar to the following appears The RTA Leq view shows a gra...

Page 106: ...to the RTA Min view A screen similar to the following appears Step 10 Use theuanddarrow keys if you want to move back and forth between the different RTA screens Step 11 Press the RUN STOP s key to s...

Page 107: ...from Logging to SLM RTA Step 2 Use theuup andddown arrow keys to highlight Recall Files and press the c check key The following appears The Data Files screen shows the currently selected record number...

Page 108: ...w an ID is modified and stored using the Setup Menu of the System 824 More detailed descriptions for specific Instrument Types e g ISM LOG or SSA will be provided in later chapters When a PC is availa...

Page 109: ...lowing the Active ID is a list of the available IDs In most cases the first ID in the list will have the symbol to the left indicating that the Active ID was originally defined by selecting that ID Th...

Page 110: ...the ID stored with that file becomes the Active ID Since the ID which was used to perform the measurement at that time may have since been modified or even deleted a tilde will appear to the left of t...

Page 111: ...ertical window covered by the vertical bar In the example of the Setup Menu it can be seen that there are more items than can be shown in one display and that those presently being displayed are at th...

Page 112: ...he desired measurement press either the Setup S key or l to exit from the Setup menu The System 824 is now ready to perform a measurement according to the Setup represented by the Active ID If the Act...

Page 113: ...and broad band frequency weighting IDs based on the LOG Instrument type will include parameters associated with automatic data storage such as Interval and Time History periods and threshold levels fo...

Page 114: ...gs Menu to Initiate Editing or Modification As mentioned above the first item on the list highlighted is the Active ID The message Edit Settings along with the symbol to the right indicates that one s...

Page 115: ...19 Step 1 Usedto highlight SLM Step 2 Pressrto produce the SLM sub menu Step 3 Usedto highlight Weighting note that the present selection is A Step 4 Pressr to open SLM Weighting Selections menu Step...

Page 116: ...the proper sub menu item then making a selection and pressing c Once one or more modifications have been made the user can follow one of three procedures Setup S will close the menu remembering its lo...

Page 117: ...b menu or Selection menu a pointer in the menu is set to the item which is highlighted at that time If in the process of continuing with the editing process a Menu is accessed once again using thelorr...

Page 118: ...list are for more advanced features and are less important for simple measurements Setting Control in the SLM View SLM settings can be adjusted from the SLM View screen To activate the SLM view screen...

Page 119: ...orrkey to change the selection The table below shows how to use the arrow keys to navigate through the settings on the SLM display ud Detector Slowr Fast rImpulse r ud Weight A rCr Flat r ud Second Va...

Page 120: ...4 24 824 Reference Manual 9 29 09...

Page 121: ...Views This chapter introduces you to the various ways of viewing measured data for a particular setup or ID of the System 824 Specifically this chapter covers the following topics Status icons General...

Page 122: ...following table describes the icons that may appear Icon Description Animated Running Figure The instrument is running and acquiring data Solid Box The instrument is stopped data available Open Box Th...

Page 123: ...er range or near the noise floor Block with Dark background and Light numerals Defines upper and lower limits of linearity range Bar and Play Symbol The instrument is in preview Current SPL and peak l...

Page 124: ...ngs contained within any of the System 824 views After you have selected the SLM RTA operating mode or instrument ID do the following to select the desired view Step 1 Press the V button and a screen...

Page 125: ...wing the levels of the last fifty samples New data points correspond to the detector and weighting selected by their respective settings The larger digital display indicates the SPL for the selected v...

Page 126: ...weighting selected in the Settings menu are for measurements such as Ln and Interval broadband levels Selectable reading This is used to view a second level which can be Leq SEL Min Max or Peak Weight...

Page 127: ...h from right to left every second The time axis in the SPL history graph shows time increasing from left to right You can use the arrow keys to select the detector weighting secondary parameter to be...

Page 128: ...viewing Thelandrarrow keys move you through each of the Any Data formats available displays Any Level Format In this view five different tables present SPL Fast and Slow Lmax Fast and Slow Lmin Fast a...

Page 129: ...ak measured with A C and Flat weighting as follows SSA Specific Views The System 824 has various displays for the SSA instrument Understanding these displays lets you take full advantage of this instr...

Page 130: ...d earlier in the General Views section of this chapter The following briefly describes the main views available to the SSA instrument Menu Items Purpose SLM SLM data with graphic display of Time Histo...

Page 131: ...and RTA Min In the above views the cursor position the vertical bar in the graph corresponds to the level and frequency values shown the left side of the display The cursor or frequency bar position...

Page 132: ...vels in each of these spectra To access the tabular displays do the following Step 1 Press the c Check key while in the RTA Live RTA Leq or RTA Max graphical views The fol lowing menu appears While in...

Page 133: ...Interval a through Interval d displays The Interval History shows a record of various sound pressure data and spectral data including spectral LNs gathered in time segments over the run time of the 82...

Page 134: ...er to turn on the Spectral Lns for the interval period go to the SSA settings menu and select Interval for the Spectra Ln setting under the Ln menu To view the Interval Spectral LN displays press the...

Page 135: ...ay menu and highlight Ln Spectrum Press the right rarrow key to access the Interval Spectral LN displays The following menu will appear Highlight Spectral and press the check c key to view the INTV Ln...

Page 136: ...displays the 6 Ln values use the up uand down darrow keys Below is an example of one of these displays SSA Time History The SSA Time History display consists of six major components Display label Reco...

Page 137: ...e SLM Time History display is shown below Display label Leq reading at cursor Other level selected in TH SPL history graph Time cursor Value of other level setup Record number Status indicator Identif...

Page 138: ...towards the right of the display TH represents time history which is the TH setup in the settings menu Value of other level This shows the value of the other levels selected in the TH setup Use the up...

Page 139: ...highlight Ln Centiles Press the right rarrow key to view the Ln displays The following menu will appear Spectral Lns are enabled by the Spectral Ln setting These data and displays are only available w...

Page 140: ...lable See the section Pause Back Erase on page 3 10 for information on the Back Erase feature Use the right rarrow key to view the SSA Ln b display The following is a brief description of each of the...

Page 141: ...displays will indicate No Data Available for1 1 octave This is a tabular display for each 1 3 octave frequency showing six Ln values for the selected frequency Below is an example of one of the displ...

Page 142: ...darrow keys to move from one spectrum Ln display to another There are six displays showing all of the frequencies for each of the six Ln values Below is an example of one of the Spectrum displays The...

Page 143: ...en using the Logging SLM LOG instrument Additionally the u or darrow keys can be used to cycle through an associated group of views There are three sets of these grouped views Any Data including Any L...

Page 144: ...time of occurrence Time History Show the time history of Leq and optionally many other levels such as Lmax Lpk or Advanced TH setup items over short duration periods Can also show wind or tachometer d...

Page 145: ...nd Overall SLM Views have five common displays which can be cycled through using therandlarrow keys Since these displays are identical they will be discussed together These displays are categorized as...

Page 146: ...View key to enter the View menu Step 2 Highlight either Current SLM or Overall SLM Press the rarrow key and one of the following screen appears Step 3 Use the uand darrow keys to highlight the desire...

Page 147: ...tting The current detector is indicated for example Slow SPL and can be Slow Fast or Impl Elapsed time This displays the length of time the current measurement has been running It will reset to zero w...

Page 148: ...rent display for example SLM Current b The display represents both Current b and Overall b display Start date time Date and time the current overall measurement began Elapsed time The Elapsed Time dis...

Page 149: ...ns each of the display s components Display label This shows the current display for example SLM Current c The display represents both Current and Overall c display Current Overall Lmax reading Displa...

Page 150: ...flat weighted value from the System 824 s peak detector along with the date and time that the peak event occurred Current Overall C Weighted Peak reading Shows the C weighted value from the System 82...

Page 151: ...level The Sound Exposure Level SEL is measured in dB This is the TWA normalized to one second Elapsed time This shows the elapsed run time accumulated since the last current overall reset This is the...

Page 152: ...Dose By definition a person receives 100 dose when exposed to a noise having a TWA equal to the selected criterion level for a time equal to the criterion time usually eight hours This corresponds to...

Page 153: ...jor components Display label Sound exposure Sound exposure level Time weighted average Elapsed Time The Exposure b display is shown below The following explains each of the display s components Displa...

Page 154: ...sed run time accumulated since the last overall reset This is the time over which the overall TWA is averaged If Takt functionality has been enabled the Exposure b display will look as shown below Exp...

Page 155: ...minus the A weighted TWA Leq over the duration of the measurement Ln Centiles Views The uand darrow keys can be used to cycle between the Current SLM Overall SLM Exposure Ln Centiles and Stats views f...

Page 156: ...ent of the measurement time By modifying the six settings you can select any six percentile values to be displayed at a time For example if you set one of these settings to 10 5 then L10 5 would be on...

Page 157: ...Elapsed time Shows the elapsed run time accumulated since the last current reset Ln graph Graph of Ln s from 1 to 99 1 being on the left 99 on the right NOTE There are two Lns per bar in the graph Th...

Page 158: ...mary of the number of times during the overall measurement that the SPL exceeded the pre programmed trigger level 1 In this example trigger level 1 is set to 115 dBA and the SPL exceeded this threshol...

Page 159: ...mple Peak I s trigger level is set to 140dBF and the Peak I level exceeded this threshold 0 times These may be considered as individual events Peak II trigger This presents a summary of the number of...

Page 160: ...s the total number of overloads If no overloads have occurred the display shows a No Overloads have occurred message instead Run Log LOG SSA The Run Log displays the start and stop times dates of the...

Page 161: ...y in relation to the other log entries currently in active memory Event Date Time The Event Date Time shows the time and date that this Log entry either started to run or was stopped Run Stop Indicato...

Page 162: ...Time History displays are shown below The following explains the display s components Display label This shows the current display for example SLM Time History Status Indicator The Status Indicator wi...

Page 163: ...Level menu in the Time History menu In this case the value of this particular parameter will always appear in the same position as shown by the Lmax display in the figure above Multiple Other Levels...

Page 164: ...sure data gathered in time segments over a set period of time An example would be a measurement where data is gathered in one hour time intervals over a 24 hour period You can access the Intervals vie...

Page 165: ...ows each measurement interval in the order that it occurred The Interval Number indicates the order of the displayed interval in relation to the other interval records Interval Date Time The Event Dat...

Page 166: ...for the LOG and SSA instruments The following explains each of the display s components Display label This shows the current display for example Interval b Interval Number The Interval displays each...

Page 167: ...yed interval Intervals c Display The Interval c display consists of six major components Display label Interval Number Interval Date Time Lpeak I Reading Lpeak II Reading Interval Duration The Interva...

Page 168: ...I reading for the currently displayed interval Lpeak II Reading The Lpeak II Reading shows the LPeak II reading for the currently displayed interval Interval Duration The Interval Duration shows the...

Page 169: ...s during this interval that the instrument s SPL Exceedance Level was surpassed Peak I Exceedances Peak I Exceedances shows how many times during this interval that the instrument s Peak I Exceedance...

Page 170: ...indicates the order of the displayed interval in relation to the other interval records Ln Centiles Readings Shows the six Ln Centiles readings for this interval Intervals f Display The Interval f di...

Page 171: ...dspeed The Average Windspeed is the numerical average of the windspeed over the duration of this interval Maximum Windspeed The Maximum Windspeed is the maximum instantaneous value of windspeed logged...

Page 172: ...The exceedance will only be saved if its duration is longer than the minimum duration setting For further information see sections LOG and SSA Triggering Settings on page 7 23 and Logging SLM Exceedan...

Page 173: ...te Time The Event Date Time shows the time and date that this exceedance occurred Leq Reading The Leq Reading shows the Leq for the currently displayed exceedance SEL Reading The SEL Reading shows the...

Page 174: ...ance records Exceedance Date Time The Event Date Time shows the time and date that this exceedance occurred Peak I Reading The Peak I Reading shows the Peak I level recorded during this exceedance Pea...

Page 175: ...Time shows the time and date that this exceedance occurred Maximum Windspeed The Maximum Windspeed is the highest instantaneous windspeed logged during this exceedance event Direction of Maximum Winds...

Page 176: ...e Time History can be displayed by pressing the ckey twice A subsequent double click of the ckey will return the display to the corresponding Exceedance Display NOTE For a detailed description of Exce...

Page 177: ...again This will open a window permitting you to jump to the first or last Exceedance or to a selected exceedance record Level at Cursor Shows the level in dB at the point in time indicated by the curs...

Page 178: ...etectors Daily Views The Daily history logs daily sound statistics including Leq 24 LDN CNEL Ln s Max Min and Peak data The measurement period is from 12 00 midnight to 12 00 midnight each day For eac...

Page 179: ...the elapsed time of this day s measurement Date This shows the day date month and year for this record Leq Reading This shows the Leq for the day LDN Reading The DNL Day Night Average Sound Level disp...

Page 180: ...rcentiles The Daily b display is shown below The following explains each of the display s components Display label This shows the current display for example Daily b Record Number Each Daily record is...

Page 181: ...pear Display label Record Number Date Duration Average Windspeed Maximum Windspeed Direction of Maximum Windspeed Time of Maximum Windspeed Wind Exceedance Data Windy Threshold Data The following expl...

Page 182: ...peed The Direction of Maximum Windspeed is the direction of the maximum instantaneous value of windspeed logged during this record Time of Maximum Windspeed The Time of Maximum Windspeed is the time h...

Page 183: ...ercent Windy Condition is the percent of the time the windspeed was above the Windy Threshold Level Windy Directional Distribution The Windy Directional Distribution is shown on a compass rose with in...

Page 184: ...y label This shows the current display for example Hourly Leq Date Date of the record Record Number The record number indicates the order of the displayed Daily record in relation to the other records...

Page 185: ...cursor to view the Leq background Leq and exceedance Leq for each hour Metrics The uand darrow keys can be used to cycle between the Metrics PassBy and Wind Tach views The Metrics View has two displa...

Page 186: ...occurring between the times 22 00 and 07 00 CNEL Reading The CNEL Community Noise Equivalent Level display shows the equivalent sound level for the entire period with a 5dB weighting applied to all so...

Page 187: ...exceedance events Exceedance Duration Total time of all exceedances Background Leq This display shows the average Leq for the total measurement period minus the combined event Leq Elapsed Time This sh...

Page 188: ...rent display for example PassBy Leq Reading This is the Leq for the Passby event including all energy between the 10dB down points centered around the maximum SEL Reading This display shows the total...

Page 189: ...e Metrics PassBy and Wind Tach views The Wind Tach View has three displays which can be accessed by simply selecting Wind Tach with the c Check key from within the main View menu then cycling through...

Page 190: ...plays the instantaneous wind direction using compass coordinate points or in degrees Frequency This displays the instantaneous frequency of the signal from the windspeed transducer This parameter is u...

Page 191: ...ce the initiation of the measurement or the last data reset Date Time of Maximum Windspeed This displays the data and time of the maximum windspeed Windy Exceedance Data The Windy Exceedance Data incl...

Page 192: ...the instantaneous wind direction indicated in both compass coordinates and degrees Percent Windy Condition The Percent Windy Condition is the percent of the time the windspeed was above the Windy Thr...

Page 193: ...9 29 09 System 824 Views 5 73 see that winds having levels above the Windy Threshold Level of 5 04 shown on the Windy b View were from the North West 59 of the time...

Page 194: ...5 74 824 Reference Manual 9 29 09...

Page 195: ...course create new setups for particular applications and add your own IDs to the System 824 The SLM RTA SSA Logging LOG and Integrating SLM ISM instruments are available in various 824 configurations...

Page 196: ...ors slow fast and impulse simultaneously Includes time history interval history exceedance history daily history Ln percentiles statistical data exposure and dual SLM current and overall Wind and Tach...

Page 197: ...ss the S SETUP key A menu similar to the following appears Step 2 Select the desired ID from the menu by using the uordkeys to highlight it then press the c key to select it That instrument s main dis...

Page 198: ...SI S1 4 and IEC 60651 standards for SLM linearity 1 3 octave filters listed are measured to the IEC 61260 standard for Class 0 linearity which is 0 3 dB The num bers in the table represent SPL levels...

Page 199: ...lay showing the six Ln values of one selected 1 3 octave filter It also displays spectra for the six Ln percentiles AC DC Output The AC DC output on the 824 is through the 3 5mm stereo connector at th...

Page 200: ...tLevel is a setting on the Ln settings menu DC out has a range of 120 dB The output signals will vary based on which instrument type is used For LOG and ISM instruments the following table defines the...

Page 201: ...l parameters including Interval data Ln statistics noise event detection and event time history records Additionally this mode provides a dynamic range of 115 dB Like other instrument modes the Loggin...

Page 202: ...e 824 can log exceedance events based on sound levels that go over a predefined threshold It can also be triggered by an event which raises the level by 10 dB This is called a Passby event LN Percenti...

Page 203: ...the following range 0 to 255 dB Exposures at higher sound exposure levels than the overall criterion level will result in a 100 dose in less time or if exposure continues the overall dose will exceed...

Page 204: ...OTE Ranges are in dB SPL using a typical 377B41 microphone with 44 1 mV Pa sensitivity See RMS Measurement Range LOG and ISM modes only on page C 11 for more 824 specifications The LOG and ISM instrum...

Page 205: ...ISM and LOG instrument types This chapter covers the following Recalling ID Setting Files Customizing Settings Menu Layout of SLM RTA SSA Settings Menu Layout of High Dynamic Range Integrating SLM IS...

Page 206: ...nt settings you will be prompted with Active ID has Changed Save Customizing Settings This section gives an example of using the standard settings in the SSA instrument The procedures in this example...

Page 207: ...enu by using the u or dkeys and then pressing the c Check key The SLM RTA screen appears The System 824 is now set to the SLM RTA SSA instrument Step 3 To access the Settings menu press the S Setup ke...

Page 208: ...SSA instrument s Detector setting is now set to Fast Press the S Setup key to close the menu and return to the SLM RTA view Settings Descriptions Within the Edit Settings menu use the u and d keys to...

Page 209: ...e instruments Title Setting SSA LOG ISM To change the Title use the r and lkeys to select each character Use the u and d keys to replace the selected letter Pressing the R Reset key clears all charact...

Page 210: ...options A The instrument uses an A weighted input filter C The instrument uses a C weighted input filter FLT The instrument uses Flat weighting see specifications for passband frequency in Appendix C...

Page 211: ...dynamic range is positioned in the normal range which is typically 20dB to 130dB when using a Lar son Davis high sensitivity microphone Low The instrument s input circuitry provides an additional 20dB...

Page 212: ...e polarization voltage to make it function properly NOTE The frequency characteristics of the 377B41 377A60 microphones change sufficiently enough in high range as to no longer meet Type 1 standards T...

Page 213: ...k that has occurred since the last current or overall reset Some histories and event counters are only able to evaluate one of the three peak detectors The Peak Weighting Setting selects which is to b...

Page 214: ...sures data using 1 3 octave filters When 1 1 octave filtered data have been selected the energy in 1 3 octave band data are summed to give octave filter data When using the translator function in the...

Page 215: ...Check key Whether for the ISM SSA or LOG instrument the Controls menu will be as shown below The following is the menu layout for the control settings Menu Items Available Settings Options AC DC Outp...

Page 216: ...ended to be connected to an external switching device possibly a push button switch The external switching device will either connect the pin to 5V pin 6 or unconnected This signal may also be supplie...

Page 217: ...nction commands Level When the logic input is connected to 5V e g switch makes contact the instrument runs When the logic input is disconnected from 5V e g switch breaks contact the instrument stops A...

Page 218: ...Peak I specified by the Peak Weight setting is over the Peak 1 Exceedance Level or when the instantaneous weighted peak level Peak II specified by the Weight setting is over the Peak 2 Exceedance leve...

Page 219: ...on when a Peak exceedance event occurs when each interval begins or when an event occurs on one of the A D channels R P I A The Logic Output turns on when either an RMS or Peak exceedance event occur...

Page 220: ...t 2 Time sets the number of seconds that the output will remain turned ON following a triggering event See Logic Output Time setting above Heater On The Heater Control output selects the functionality...

Page 221: ...ater described in greater detail Ovll Exchange LOG This setting affects the System 824 s primary or overall memory buffer The Overall Exchange rate setting sets the exchange rate sometimes called the...

Page 222: ...s in the LAvg time weighted average which is merely a convenient rep resentation of the long term average noise level as opposed to the RMS noise level Ovll Threshold LOG This setting affects the Syst...

Page 223: ...e rate of 5dB for example means that 5dB may be added to the permissible exposure level every time the exposure duration is cut in half This setting provides the following four options This setting af...

Page 224: ...reshold to 0dB Crnt Criterion LOG The Crnt Criterion sets the TWA level which constitutes 100 dose for the current measurement The 100 dose occurs if a person is exposed to that level for the criterio...

Page 225: ...ent then the Back Erase feature is no longer available See the section Pause Back Erase on page 3 10 for information on the Back Erase feature Yes The six Ln levels are stored for the overall measurem...

Page 226: ...measure six Ln values for each 1 3 octave The setting options provided are Spectral Lns can be enabled as an Overall measurement or as a function of each Interval History record None Spectral Ln s ar...

Page 227: ...escribed in greater detail SPL Excd Lvl 1 LOG SSA The SPL Excd Lvl 1 sets the SPL trigger level that exceedance records are triggered from LOG only You can also view a count of the SPL events on the S...

Page 228: ...d by the Weight setting This setting can include any integer value within the following range 0 to 255 dB Pk Excd Lvl 2 LOG SSA The Pk Excd Lvl 2 sets the trigger level for the secondary peak detector...

Page 229: ...o windspeed wind direction This feature is used most frequently with external weather transducers providing an analog pulse train whose frequency is proportional to windspeed and a DC voltage proporti...

Page 230: ...ither the LOG or SSA instrument active press the S SETUP key to access the Edit Setup Menu Using the uand darrow keys highlight the Advanced item and select it using the r arrow key or the c Check key...

Page 231: ...d with this factor are as follows Direction Unit Compass Degrees Percent Volts Number Wind Tach No Yes Windy Threshold nnn n or nnnnn Wind Excd Level nnn n or nnnnn Windy Hysteresis nnn n or nnnnn Win...

Page 232: ...W NW NNW Degrees Degrees reports wind direction in degrees from 0 to 360 Percent Percent would typically be used to report throttle position over the range 0 to 100 as a percent of full throttle Volta...

Page 233: ...s defined above Wind Exceedance Level The wind exceedance level represents a second threshold level higher than that associated with Windy Most often this is defined to be the wind level above which a...

Page 234: ...this case select Ext If Int is selected the signal connected to the System 824 input will be used to determine the Wind Tach level This setting will allow the measurement of the frequency of an acoust...

Page 235: ...truments Each setting is described later in greater detail Menu Items LOG instrument Available Settings Options Hist Enable No Yes Hist Period 1 to 255 Period Units 1 32s 1 0s 10 0s 60 0s Other Level...

Page 236: ...s SSA instrument Available Settings Options Hist Enable No Yes Hist Period 1 to 255 Period Units 1 32s 1 0s 10 0s 60 0s Resolution 0 1 dB 1 0 dB TH Setup Activates a set of 3 displays used to configur...

Page 237: ...will be rounded to the nearest 5 second interval and a warning Setting Conflict will appear If the Period Units equal 1 32nd of a second then the period will be forced to a count of 160 5 seconds 1 32...

Page 238: ...Lmax that has occurred during the time history period The Any Data information stored with the Time History is accessed through the Time History menu under the View key Advc Stores up to 38 different...

Page 239: ...ion or check box The Check c key toggles the selection on or off The Reset key R will uncheck all the items on the current display To move to the next screen a b or c highlight Next and press the Chec...

Page 240: ...e second to nearly one hundred hours The Interval feature is particularly useful when monitoring noise levels for extended periods of time because you can determine how the statistical makeup of the a...

Page 241: ...Intv Period LOG SSA Intv Period sets the time interval between successive interval storage operations These storage operations continue either until the instrument is stopped or runs out of memory You...

Page 242: ...is setting provides the following two options No The six LN levels are not stored with the interval record Yes The six LN levels are stored with the intervalre cord NOTE If Intervals are enabled and I...

Page 243: ...means that 5dB may be added to the permissible exposure level every time the exposure duration is cut in half This setting provides the following four options 3dB The 3dB default option is the most co...

Page 244: ...peak level Pk 1 or Pk 2 going above or exceeding a predetermined level For further detail see the section LOG and SSA Triggering Settings on page 7 23 Triggering LOG The Triggering menu defines event...

Page 245: ...xed level triggering Note Minimum duration is not considered when using the Exceedance Trigger in Passby Mode PassBy Enables 10 dB Passby triggering Excd Time LOG The Excd Time setting allows you to s...

Page 246: ...he following two options Yes Storage of daily history data will occur No Daily data will not be stored Daily Ln s LOG Daily Ln s allows you to store six Ln percentiles with the Daily History data This...

Page 247: ...nt parameters for both the overall and current measurements This setting provides the following two options No The data report will not print Yes The data report will print Setup Report LOG SSA The Se...

Page 248: ...The peak I histogram report will print Pk 2 Histogram LOG The Pk 2 Histogram either enables or disables the printing of the Peak 2 histogram report The histogram report contains a histogram of the Pea...

Page 249: ...q and optionally one selectable level Lpk I Lpk II or Lmax basic measurement parameter for each time history period This setting provides the following two options No The history report will not print...

Page 250: ...e Manual 9 29 09 SLM Detector Slow Fast Impl Weighting A C FLT Gain A C FLT Transducer Condnsr Elctret Direct Random Corr No Yes Pk Weighting A C FLT RTA RTA Detector Slow Fast RTA Weighting A C FLT B...

Page 251: ...Setting Files 7 47 Intervals Intv Enable No Yes Intv Period hh mm ss Intv Time Sync No Yes Intv Save Ln s No Yes Intv Auto Stop No Yes Intv Threshold 0 255 dB Intv Exchange 3dB 4dB 5dB 6dB Intv Spect...

Page 252: ...Units 1 32s 1 0s 10 0s 60 0s Resolution 0 1db 1 0db TH Setup Activates a set of 3 displays used to configure what time history data will be stored See the section Advanced Time History LOG SSA on page...

Page 253: ...lt 33 33 Ln 4 Percent Selectable default 50 Ln 5 Percent Selectable default 66 67 Ln 6 Percent Selectable default 90 Spectral LN None Overall Interval Triggering SPL Excd Lvl 1 0 255 dB default 115dB...

Page 254: ...ttings The Integrating SLM ISM Edit Settings menu has 16 configurable items Provided in this section is a table depicting the menu layout of the ISM instrument s Standard Settings ISM Setting Menu Ite...

Page 255: ...Detector Slow Fast Impl Weighting A C FLT Range Normal Low High Transducer Condnsr Elctret Direct Random Corr No Yes Pk Weighting A C FLT Crnt Exchange 3dB 4dB 5dB 6dB Crnt Threshold 0 255 dB Advance...

Page 256: ...rovided in this section is a table depicting the menu layout of the LOG instrument s Standard Settings LOG Settings Menu Items Submenu Available Settings Options Title User customized text entry SLM D...

Page 257: ...0 255 dB default 90dB Ln Start Level 0 99dB default 15dB Ln 1 Percent Selectable default 1 67 Ln 2 Percent Selectable default 8 33 Ln 3 Percent Selectable default 33 33 Ln 4 Percent Selectable default...

Page 258: ...t 10s 60s Other Level None default Pk II Pk I Lmax Advc Resolution 0 1dB default 1 0dB Adv TH Activates a set of 3 displays used to configure what type of time history data will be stored See Advanced...

Page 259: ...No Intv Auto Stop Yes No default Intv Threshold 0 255 dB Intv Exchange 3dB default 4dB 5dB 6dB Excd History Triggering SPL Excd Lvl 1 SPL Excd Lvl 2 PK 1 Excd Lvl PK 2 Excd Lvl Hysteresis Excd Enable...

Page 260: ...Daily Ln s Yes No default Define Report Data Report Yes default No Advanced See Advanced Menu below Menu Items Submenu Available Settings Options Controls See also Control Settings _ SSA LOG on page 7...

Page 261: ...eak R P Intv R I P I R P I A D R A P A R P A I A R I A P I A R P I A R S Excd Logic Out Time 0 255 sec Logic Out 2 Off RMS Peak R P Intv R I P I R P I A D R A P A R P A I A R I A P I A R P I A R S Exc...

Page 262: ...5 255 99 Wind Units 4 alphanumeric characters Direction Units Compass 16 ordinates Degrees 0 360 Percent 0 100 Volts 0 2 49 Number 0 255 93 Wind Tach No Yes Windy Threshold Level 0 0 65 535 Windy Exce...

Page 263: ...he System 824 s different views The available Check menu options vary between an instrument ID s different views The options available from each display allows the user to change settings peculiar to...

Page 264: ...sing the c Check key from within an Instrument ID s view The following is an example of using the Check menu from a SLM view to change the Detector setting from the selected instrument s SLM display U...

Page 265: ...keys to highlight Weighting then press the c Check key or the r arrow key A menu similar to the following appears Step 5 Highlight the desired weighting and press the c Check key Pressing the right r...

Page 266: ...wing describes the Check Menu setting The following screen appears when accessing the Check menu from the SLM view Mark Display Pressing the right rarrow key when Mark is highlighted puts you in the M...

Page 267: ...owing menu appears When Set Mark is initiated by pressing the Check c key a marker is placed into the time history record at that point in time With Set Mark highlighted press the Check c key to place...

Page 268: ...2 1 1 2 1 4 1 8 dB per dot pixel Pressing therarrow key on the Graph menu item allows you to adjust the graph settings through a menu A screen similar to the following appears The u or d key allows y...

Page 269: ...s menu Controls Settings Menu Allows you access to the Settings menu in the Controls area that is usually accessed from the SETUP S key This is a shortcut to the Controls settings so you can modify th...

Page 270: ...q RTA Max and RTA Min views Following is a chart of the check menu with a description of each menu item Menu Items Purpose Mark Puts a marker in the time history Settings Modifies the SLM settings for...

Page 271: ...enu with a description of each menu item In the Leq Spectrum display press the Check c key and the following menu appears Graph Changes the scaling of the instrument s SLM history graph Bandwidth Sele...

Page 272: ...enu Items Purpose ByTime Allows you to view the Leq for each interval over time Intv Data Allows you to view the Interval a through Interval e displays Max Min Spectra Allows you to view the Max or Mi...

Page 273: ...the Check c key while viewing the Run Log display and the following check menu appears Menu Items Purpose Broadband Spectrum Allows you to view the broadband history graph or the spectral data Locate...

Page 274: ...e three different Check menus contained within the Ln Centiles views Press the Check c key while viewing the Ln Centile s broadband displays and the following check menu appears Menu Items Purpose Fir...

Page 275: ...pears Menu Items Purpose Enable Ln Enables or disables Ln data Start Level Sets the minimum dB level to be calculated in the Ln data Ln 1 Percent Changes the percentage for Ln 1 Ln 2 Percent Changes t...

Page 276: ...be calculated in the Ln data Ln 1 Percent Changes the percentage for Ln 1 Ln 2 Percent Changes the percentage for Ln 2 Ln 3 Percent Changes the percentage for Ln 3 Ln 4 Percent Changes the percentage...

Page 277: ...7 73 for a description Current SLM Overall SLM Check Menu Current SLM and Overall SLM views have access to the following Check menu Exposure Check Menu The Exposure view has access to the following C...

Page 278: ...change rate that is used to calculate the overall TWA Ovll Threshold Sets the threshold for computing the overall time weighted average TWA Ovll Criterion Sets the TWA level which constitutes 100 dose...

Page 279: ...ercentiles settings for the selected instrument Graph Changes the scaling of the instrument s Ln b Centiles graph Menu Items Purpose SPL Excd Lvl 1 Sets the lowest SPL trigger level SPL Excd Lvl 2 Set...

Page 280: ...ls view has access to the following Check menu Menu Items Purpose Mark Puts a marker in the time history record Locate Allows you to locate a time history record Settings Modifies the Time History Set...

Page 281: ...a through Excd b the following menu appears after pressing the Check c key Following is a chart of the check menu with a description of each menu item In the Excd Time History display press the Check...

Page 282: ...pressing the Check c key Following is a chart of the Daily History check menu with a description of each menu item Menu Items Purpose Excd Data View Excd a and Excd b displays Locate Locates a specifi...

Page 283: ...ith a description of each menu item NOTE Check menus are not available for the Metrics PassBy and Wind Tach views Menu Items Purpose Daily Data Displays Daily data First Displays the first hourly reco...

Page 284: ...7 80 824 Reference Manual 9 29 09...

Page 285: ...reports when printing to a laser printer because of the instru ment s PDL 3 page description language capabilities to draft quality tabular data reports that can also be printed to a dot matrix print...

Page 286: ...nt Print menu available The screen shown is for the SSA instrument Step 2 Press the P Print key The following screen appears The TAL and FFT instruments do not generate any reports The Print menu prov...

Page 287: ...u and d arrow keys to highlight Printer Type Printer Baud and Flow Control and then press the c Check key to select the correct option for each Recall Format Summary Tailored All short All long None e...

Page 288: ...ry menu item This means that a report will be printed by highlighting Summary and pressing the Check c key The title printed on your report will correspond to the Title setting you have configured in...

Page 289: ...and print tailored reports for the SSA and LOG instruments Selecting Tailored Report under the Print menu copies the report settings under Define Report from the Setup Menu for the SSA and LOG instru...

Page 290: ...ight the Advanced item then select it using the r arrow key or the c Check key The following screen appears Step 3 Using the uand darrow keys highlight the Define Report item then select it using the...

Page 291: ...ost Using the Recall Format SSA and LOG instruments only The Recall Format menu allows you to customize the Sum mary report or the Tailored report and gives you two more customized reports called All...

Page 292: ...t Summary Tailored All Short All Long or None Enabled Default Settings Values for the Recall Format Reports The following tables show the default settings for each of the templates available from the...

Page 293: ...5535 Selects the highest interval record to be printed Hist Report No You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history...

Page 294: ...tart Time Leq Max Peak Overloads Unweighted Peak Duration SEL and Spectrum Intv Report No Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the L...

Page 295: ...be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak1 Histogram report by...

Page 296: ...rval period Hist Report No Leq for each time history period Print Range Intv Report Short You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the low...

Page 297: ...Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Log Report Yes The run stop l...

Page 298: ...est time history record to be printed Histograms SPL Histogram No You can customize the SPL Histogram report by choosing the long or short report Lowest Level 040 Selects the lowest SPL histogram leve...

Page 299: ...ecord 65535 Selects the highest interval record to be printed Hist Report Yes You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time...

Page 300: ...the LOG instrument SPL Histogram Yes The 6 Ln values Lmax Lmin and a bargraph of the level distribution Intv Report Short Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short re...

Page 301: ...10 Selects the lowest Peak1 histogram level to be printed Highest Level 160 Selects the highest Peak1 histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram...

Page 302: ...st Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 1 0 Selects the SPL histogram resolution Pk 1 Histo...

Page 303: ...ing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 99999 Selects the highest time history record to be printed Histograms SPL Histogra...

Page 304: ...Lmin Lmax Peak Ln s exceedance and calibration logs Setup Report No Print the settings and their values for the SSA instrument Intv Report No Leq SEL Lmin Lmax Peak Uwpk exceedances time date and dur...

Page 305: ...vel to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution None Enabled Report LOG instrument Report Settings Low...

Page 306: ...owest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Hi...

Page 307: ...light the Customize item then select it using ther arrow key or the c Check key The following screen appears Step 3 Use the u and d arrow keys to scroll through the available report settings Use the c...

Page 308: ...Yes Intv Report No Short Long Hist Report No Yes Print Range Intv Report No Short Long Lowest Record Highest Record Hist Report No Yes Lowest Record Highest Record Histograms SPL Histogram No Yes Lowe...

Page 309: ...ble options under the Customize menu for the LOG instrument Menu Items Options Unformatted No Yes Data Report No Yes Log Report No Yes Setup Report No Yes SPL Histogram No Yes Excd Report No Short Lon...

Page 310: ...gram No Yes Lowest Level Highest Level Resolution Pk 2 Histogram No Yes Lowest Level Highest Level Resolution RTA instrument Report Options Description Data Report No Yes Name and Address of Company a...

Page 311: ...print Lowest ByTime 0 65535 The lowest ByTime Spectrum to print Highest ByTime 0 65535 The highest ByTime Spectrum to print RT 60 Report No Yes Prints the calculated RT60 for every octave or 1 3 octav...

Page 312: ...8 28 824 Reference Manual 9 29 09...

Page 313: ...of the System The System 824 should be configured as shown in Figure 1 1 on page 1 10 with the preamplifier connected to the front of the instrument and the microphone connected to the end of the prea...

Page 314: ...the funtionality of each of these see System 824 Virtual Instruments on page 6 1 Select the desired measurement mode ISM LOG or SSA as described in section Selecting and Modifying Instrument Definiti...

Page 315: ...nstrument types on page 7 8 Calibration The System 824 automatically changes the frequency weighting to C Weighting during the calibration process Therefore calibrators having frequencies which corres...

Page 316: ...on the display The noise due to the front end electronics and the microphone preamplifier are known but the thermal noise of the microphone must be entered by the user based on specifications provide...

Page 317: ...s the energy over a specific period of time It may be as short as 1 32 second in a time history which may be as long as 24 hours As a result it does not include decay artifacts of older instruments th...

Page 318: ...n above For this parameter you have a choice of three detectors averaging time Slow Fast Impulse and you have a choice of three frequency weightings A weight C weight Flat Similarly you have a choice...

Page 319: ...or should place himself at a distance behind the tripod mounted meter or extend the hand held meter as far from the body as is comfortable If desired a microphone extension cable may be placed between...

Page 320: ...and preamplifier as shown below To install the windscreen hold the meter in one hand and the windscreen in the other Insert the microphone preamplifier assembly into the opening in the windscreen as s...

Page 321: ...M and LOG Modes In the ISM mode there are three range setting available Low Normal High Although the range setting does not always appear on the SLM display it can be found by repeatedly pressing eith...

Page 322: ...High range Press the S key the rkey highlight SLM press the c key highlight Range and press the c key to obtain the following display Highlight the desired range and press the c key to make the selec...

Page 323: ...t aspects covered are the following Stop Pause and Erase Functions in section Stop Pause and Back Erase Functions on page 2 8 Changing the Detector of the displayed SPL value in section Changing the d...

Page 324: ...ing and immediately following the measurement time interval Averaging Time The averaging time is determined by how long the measurement is allowed to run as indicated by the digital display in the low...

Page 325: ...ted by the dark regions with light numbers as indicated below Changing the range ISM and LOG Modes or gain SSA Mode will change these limits For very low high level measurements it may be necessary to...

Page 326: ...the data measured may not be accurate due to the overloaded condition which occurred during the measurement interval Reset Press the R key to reset the measurement This function is described in greate...

Page 327: ...at and detection Slow Fast and Impulse Peak values are measured for A C and Flat frequency weighting These max values represent the highest value of each which was measured during the measurement time...

Page 328: ...8 To measure and store data over a series of equal time intervals set Interval Autostop Intv Auto Stop to Off The interval time can be set from 00 00 01 hr min sec to 99 59 59 in steps of 1 second Tim...

Page 329: ...24 can be setup to measure data associated with Exceedance Events defined as instances where the sound pressure level exceeds a user selected threshold For a detailed description of setting up the Sys...

Page 330: ...9 18 824 Reference Manual 9 29 09...

Page 331: ...nload section provides a means by which to retrieve the measurement data from the 824 The translate section provides support for translating the downloaded measurement data and displaying or print ing...

Page 332: ...tility Software The 824 utility software will automatically begin the installation process The installer program will prompt you through the installation A message will appear indicating that the soft...

Page 333: ...on the 824 you must connect the 824 to the 824 Utility software To connect to the 824 Step 1 Attach the CBL006 to the 824 and to the serial port on the computer as described earlier Step 2 Start the...

Page 334: ...utton After a successful connection the setup window will appear with a system setup in the setup list box The 824 s serial number and title will be displayed on the setup dialog box screen 824 Utilit...

Page 335: ...his button will allow the user to create a new setup that can then be saved to disk or saved in the 824 Open a setup from a computer file This button will allow the user to retrieve previously stored...

Page 336: ...tup list box will list all setups that have either been created or retrieved from the Download window button This button will open the download section of the 824 Utility program Translate window butt...

Page 337: ...ngs dialog section will allow you to manipulate the setup Retrieving setups from the 824 Setups stored in the 824 can be retrieved by clicking on the Get Setup button on the tool bar or by selecting G...

Page 338: ...n the setup dialog box right side of the The three letter Larson Davis assigned name is listed in the blue Ovals This indicates the type of instrument ID for which the setup was created P stands for a...

Page 339: ...libration Power Date Time Controls or Modem and then send the modified setup to the 824 To store the modified setup select the Save Setup to 824 menu item from the File menu or click on the Store Setu...

Page 340: ...lating a Setup To change any of the variables for a particular user defined setup select the setup The appropriate setup tab dialog will appear at the right of the setup list box Select the setting yo...

Page 341: ...xample it is not possible to delete a permanent 824 setup so the Delete Setup menu item will be disabled if a permanent 824 setup is selected The Rename Setup button allows you to rename the selected...

Page 342: ...etup is automatically updated each time the 824 Utility is connected to the 824 The 824 Utility program will bring up a standard windows save dialog box where the file name and location of the setup c...

Page 343: ...u want The setup appears in the Select Setup list box You can then select highlight the desired setup in the list The high lighted setup can then be sent to the 824 by selecting the Save Setup to 824...

Page 344: ...eate new setups by selecting the New Setup menu item from the File menu or by selecting the New Setup but ton on the tool bar From the displayed dialog box select the type of new setup Press the OK bu...

Page 345: ...nu select Save setup to a file In the Save setup to a file window type in default under File name and select Save The new setup is now defined for a particular instrument ID and can be modified from t...

Page 346: ...824 Deleting an Existing Setup To delete an existing setup right click on the user defined setup in the left hand side of the screen and select Delete Setup from the popup menu NOTE This section appli...

Page 347: ...d a new setup the setup must first be stored to the 824 before it can be locked Downloading Measurement Data To display measurement data stored in the 824 select Down load View from the View menu or h...

Page 348: ...824 Fol lowing the active measurement is a list of all other Data Files stored in the 824 The measurements are identified the same way the setups were identified in the Setup List Box in the setup por...

Page 349: ...files with the date the file was created as the file name as a default It will also download the file to the 824 Utility Folder as a default The option to specify a file name and destination folder is...

Page 350: ...h to the specified directory now show on the download screen These settings will only apply for the currently selected measurement NOTE This process will have to be repeated for each measurement to be...

Page 351: ...s for each measurements Selecting Active Measurements or Data Files There are two types of measurements that can be down loaded The first measurement in the list is the Active mea surement and is repo...

Page 352: ...y choose to view all of them simultaneously by selecting ALL binary or you can select the file type from the list If you selected ALL binary highlight one or more of the files in the measure ment list...

Page 353: ...om the trans lated file saved as csv or txt and launch a spreadsheet or text editor Once you have selected the data viewing options click on the OK button to start the download process Checking this b...

Page 354: ...in the spreadsheet or text program To view the other records they will have to be selected and opened in the viewer program from the directory where they are stored If you selected Save Binary Data an...

Page 355: ...dl ISM 28Jun15s slmdl SSA 28Jun15l slmdl LOG 28Jun15r slmdl RTA 28Jun15f slmdl FFT 28Jun15a slmdl AUD 28Jun15t slmdl TAL The translated files will have either a csv extension or a txt extension depend...

Page 356: ...print the desired records from the file The left portion of the Translate window functions as a Win dows file tree Select the folder that contains the down loaded measurement files that you wish to t...

Page 357: ...file will contain several records depend ing on the type of setup used and the data stored Selecting a Data set to view After the downloaded file is located click on the data you wish to view Download...

Page 358: ...9 The data is displayed on the right side of the screen If the data record is too large to be effectively displayed in that area a message will appear at the top of the displayed record indicating tha...

Page 359: ...824 Utility Software 10 29 Printing a Translated File To print the translated data select the file that you wish to print from the translate window Display the file as described earlier Select Print f...

Page 360: ...10 30 824 Reference Manual 9 29 09 The default Windows printer dialog box will be displayed The report will be printed in a text format similar to that shown below...

Page 361: ...enu item from the File menu or the Launch Spreadsheet button on the tool bar When you select the View Data in Spreadsheet menu item the 824 utility program will attempt to launch the program associate...

Page 362: ...for Overall and Interval Data One of the features of the 824 Utility software is the ability to store histograms in both the LOG and SSA virtual instru ments for overall interval and daily data LOG on...

Page 363: ...hen viewing the histogram data the changes made in this window will be immediately displayed The Overall area allows you to set the viewing parameters for the overall SPL Peak and Unweighted Peak hist...

Page 364: ...ves you the flexibility to set the options for the calculation and display of the RT60 values You must first take an autostore ByTime measurement Download the measurement and go to the Translate view...

Page 365: ...are round the RT60 values to two decimal places However because the 824 uses logarithmic arithmetic to calculate the RT60 value and the 824 Utility software uses double precision to calculate the valu...

Page 366: ...10 36 824 Reference Manual 9 29 09...

Page 367: ...RT60 analysis Room Criterion Acoustic Impulse Event Analysis Pass by Event analysis The 824 RTA option provides the following features RTA for fast spectral data Performs room acoustics RT60 RC NCB H...

Page 368: ...press the c check key The RTA Live view will now be displayed Press the S SETUP key again to return to the SETUP menu At the top of the Setup menu Edit Settings will be highlighted Press the c check k...

Page 369: ...following in this manual For data storage see Taking Measurements and Storing Data on page 4 5 For printing RTA reports see Printing Reports on page 8 2 For I O commands see Serial Port Interface Rem...

Page 370: ...Gain dB 20 10 0 10 20 30 40 50 Bandwidth 1 1 1 3 Detector Lin Exp Lin Detc Time 0 0025 to 99 9975 sec Exp Detc Time seconds 1 32 1 16 1 8 1 4 1 2 1 2 4 8 16 32 64 Exp Store Rate 1 2 second 1 8 second...

Page 371: ...t Time Count Trigger Level 0 0 255 9 dB Trigger Time 00 0000 to 99 9975 sec Trig Samples 0 65535 Trig Logic In Low High End End mode Never L L L Input Time Count End Level 0 0 255 9dB End Time 00 0000...

Page 372: ...he voltage level delivered to the measuring portion of the meter from the microphone and preamplifier Bandwidth Setting Selects 1 1 or 1 3 octave filter bandwidth for real time analysis Detector Setti...

Page 373: ...l time time between successive samples is equal to the exponential detector time multiplied by the exponential store rate 1 2 1 8 NOTE For example if the detector time is 1 8 and the store rate is 1 2...

Page 374: ...e data is automatically stored in the Autostore record if Save ByTime is set to Yes For setups with a linear detector spectra are stored once every linear detector time When an exponential detector is...

Page 375: ...ct a filter or flat overall level as a trigger source Arm Settings Menu Arm Mode Elapsed time and qualifying times are evaluated only when a new ByTime sample is created This causes the minimum effect...

Page 376: ...arm 0 0 255 9 dB Arm Time When the Arm Mode is set to Time the Arm Time must expire before the 824 will arm This is also a qualifier for the level settings If the time is non zero then the level cond...

Page 377: ...t The 824 starts recording an Autostore when the logic input line changes to Trigger Logic In state Time The 824 starts recording an Autostore after Trig ger Time seconds Count The 824 starts recordin...

Page 378: ...re record when the logic input line changes to the Trig Logic In state Low High End Settings Menu End Mode The measurement ends when the following conditions are met Never The measurement continues un...

Page 379: ...The 824 stops recording an Autostore record when the End Time has been satisfied 00 0000 to 99 9975 seconds End Samples The 824 stops recording an Autostore after End Samples has been satisfied 0 6553...

Page 380: ...records are the same length Average The measurement repeats like repeat above except that the spectra are averaged with the preceding spectra Repeat Count Allows the user to select how many times the...

Page 381: ...ohm resistor when asserted or zero volts when not asserted Pin 1 is the ground signal The Cal output is on pin 7 of the control connector and will be driven to 5 volts through a 10 000 ohm resistor w...

Page 382: ...ated for the data between 5 and 35 dB down from the max The available selections are 5 dB 10 dB 15 dB 20 dB 25 dB 30 dB Auto RT60 The Auto RT60 setting when enabled automatically calculates the RT60 f...

Page 383: ...two types of measurements The RT60 A and RT60 B RTA instruments are accessed from the S SETUP key RT60 A Although the settings are predefined in RT60 A and RT60 B they can be changed at any time and u...

Page 384: ...Trigger Mode L End Mode Time End Time 3 0 seconds Then Stop Qualifying Background Noise Rooms RTA ID This ID sets up the System 824 to measure and evaluate background noise according to the RC and NCB...

Page 385: ...e 10 0000 seconds End Then Stop Display Views This next section will explain the various displays available under the V View key Once a measurement has been taken the 824 allows you to view the result...

Page 386: ...seconds a display spectrum is generated and displayed to keep the live data current If the sample time is less than 0 25 seconds the display still updates every 1 4 second The RTA Live display shows t...

Page 387: ...the s R S key If Autostore is enabled Leq Max and Min will be reset at every trigger or run if Triggering is off otherwise they will accumulate for each R S measurement until manually reset Max The M...

Page 388: ...The Times display shows the date and time when the overall measurement began and the date and time when the last measurement ended These times are not affected by the automatic reset or the manual Cu...

Page 389: ...ey to bring up the View Trigger display view menu The Trigger display view offers 2 choices Status and Setup Use the c check key to select the Status display Status The Trigger status display shows th...

Page 390: ...1 second When the level of the 1 kHz filter drops below 80 0 dB for 0 seconds immediately the 824 is triggered and begins taking a measurement Pressing the c Check key provides quick access to the tri...

Page 391: ...when the Autostore setting is set to Yes The Autostore includes summary data Leq Max and Min spectra covering the entire duration of the Autostore and optionally ByTime spectra RT 60 analysis of the B...

Page 392: ...re Leq display shows a bin by bin equivalent level of all samples while the Autostore is triggered To move to the next Autostore display press the c check key and then the rright arrow key Display lab...

Page 393: ...twice while in any of these display views will toggle you between the Leq Max and Min autostore displays The uup and ddown arrow keys will move you to the next or previous Autostore records Display l...

Page 394: ...out to the main View Autostore menu showing Autostore ByTime and RT 60 menu items Use the d down arrow key to highlight the ByTime menu item and press the rright arrow key to access the ByTime menu an...

Page 395: ...are currently looking at record number 597 With the uup and ddown arrow keys you can view each ByTime spectrum sample that was recorded Use the lleft and rright arrows to move the cursor to look at ea...

Page 396: ...us and next ByTime sample ByTime Spectrum Check Menu As discussed earlier in order to move between the ByTime spectrum display and the ByTime Graph display you pressed the c check key twice toggling b...

Page 397: ...veraging displays and menus are covered later in this chapter Average Add spectrum to spatial average or view spa tial spectra average If 1 3 octave filters are selected the Rooms display gives you th...

Page 398: ...find the record you would like to view Locate Locate an Autostore ByTime record Next The next Autostore record Prev The previous Autostore record First The first ByTime record Last The last ByTime re...

Page 399: ...ature that allows you to view a large amount of time data in the ByTime Graph view A scale factor of 1 to 1024 can be selected A scale factor of greater then 1 will cause multiple pieces of time data...

Page 400: ...o select routine will automatically locate the cursor to be 5 dB below the maximum level The auto select is executed on demand from the check menu and the first time the RT 60 display is selected Ther...

Page 401: ...aph H See page 2 13 for explanation View Back Returns you to the previous display Spatial Avg Views The Spatial Averaging facilities allow user selected spectra to be averaged on an equal weighting ba...

Page 402: ...select the Spatial Avg display Spatial Avg The Spatial Avg display shows the spectra which have been currently averaged NOTE If the right digit of the annunciator is numeric then it will auto increme...

Page 403: ...splay is shown Cancel nothing happens and the previous display is shown Once one or more spectra have been averaged they can be stored into the Avg History Spatial Avg Check Menu The Spatial Avg check...

Page 404: ...e Spatial Avg check menu to access the Avg History display In order to clear the Avg History records an overall reset is required Use the uup and ddown arrow keys to move to the previous and next spat...

Page 405: ...ged as one record Average Add spectrum to spatial average Rooms View Room Criteria for this spectrum View Back Return to the previous display Graph Adjusts the vertical graph scale and offset Rooms Vi...

Page 406: ...s is chosen from any spectrum check menu The NCB status indicator can show the following Under indicates that SIL speech interference level is under the defined range for NCB Over indicates that SIL i...

Page 407: ...can show the following Under indicates that Lmf mid frequency average level is under the defined range for RC Over indicates that Lmf is above the defined range for RC N indicates the RC is Neutral RV...

Page 408: ...played when Rooms is chosen from any spectrum s check menu The HTL status indicator can show the following Pass indicates the recording environment is suitable to produce recordings without audible ba...

Page 409: ...tion Features The FFT option has the following features 400 line FFT 1 Hz to 20 kHz Hanning Flat Top or Rectangular window Bandwidths of 200Hz 500Hz 1kHz 2kHz 5kHz 10kHz and 20kHz Count averaging 1 to...

Page 410: ...ings menu NOTE See System 824 Virtual Instruments on page 6 1 for a more detailed explanation on selecting instrument definitions The menu layout of the FFT settings is shown in the table below Menu I...

Page 411: ...is setting provides the following options 20 10 0 10 20 30 40 50 Bandwidth The frequency resolution for each line is the bandwidth divided by the lines setting With the bandwidth set to 20kHz and 400...

Page 412: ...ovides finest frequency resolution Hanning good compromise between amplitude accuracy and frequency resolution Most commonly used for general measurements Flat top provides best amplitude accuracy Oft...

Page 413: ...tion The Random Corr setting gives you the option of turning on a digital filter to provide the correction necessary to provide a random incidence response when measuring with a free field microphone...

Page 414: ...ed by the number of counts selected for Count Averaging For more detail on Snapshots see Snapshot on page 12 11 FFT Display The FFT data displays are accessed through the View V key To select the FFT...

Page 415: ...one eighth of the 400 lines on the display The down darrow key zooms out to a full screen display of the FFT The zoom factor is shown graphically as a horizontal bar at the bottom of the bar graph The...

Page 416: ...ers the following options Store Snapshot Stores the current FFT spectrum at that moment in time The THD as calculated in the 824 satisfies all of the requirements for ANSI S3 6 THD Activates the THD d...

Page 417: ...y and selecting the highest peak The actual frequency is extrapolated from the fundamental bin frequency and the highest sideband bin frequency The second harmonic is found by doubling the fundamental...

Page 418: ...ny of the first four bins There must not be excessive DC or near DC levels THD n must be at least 10 dB below the fundamental level There must be an identifiable tone The fundamental frequency will be...

Page 419: ...ot Once you have stored an FFT snapshot by accessing Store Snapshot from the FFT check menu you can view the snapshot data by pressing the View V key The following menu appears Highlight Snapshot and...

Page 420: ...t The first Snapshot record Last The last Snapshot record Find Finds the specified Snapshot record Graph Adjusts the graph scale and offset See 824 Reference Manual Graph Level Allows numerical entry...

Page 421: ...fferent Reference For measurements of non acoustical parameters such as acceleration it is more appropriate to express the measurement in decibels relative to a different reference using units typical...

Page 422: ...ond digital readout can be created which will show the amplitude in linear units This is particularly useful when using an accelerometer and desiring to readout the amplitude in units such as g m s2 f...

Page 423: ...s Volt m s2 and use that value in the equation for Linear Scale Setup of Linear Units Readout The items to be defined to implement this feature are Linear Units and Linear Scale which appear in the FF...

Page 424: ...ve display with linear units The following explains each of the display s components In this case it shows 20 12 milli g acceleration Standard dB level at cursor This is the dB display which appears w...

Page 425: ...elerometer but the dB level may be of use To calibrate the dB level to some usable value for acceleration requires the use of an accelerometer calibrator We use the PCB 394C06 Portable 1g Handheld Sha...

Page 426: ...a 50mv g accelerometer would have a Linear Scale of 20 LOG 1 0 05 or 26 02dB The Linear Unit setting is a text field so that the units may be annunciated as desired The Linear Value is calculated in t...

Page 427: ...and a linear level directly from the 824 display Calculate the linear reference level what linear level gives 0dB using this formula R L 10 D 20 where R is the linear reference level for the current c...

Page 428: ...uared The calibration offset is calculated with this formula 5 accurate LCAL 20 log 4 467 nanovolts Vref Where LCAL is the calibration offset being calculated Vref is the desired reference voltage the...

Page 429: ...ng to a special key value of 224 48 that allow the calibration settings to be entered directly the key is to prevent accidental calibration alteration Highlight the CAL Offset setting line and press t...

Page 430: ...enter your LCAL value Command Q227 Response 7 00 Verify LCAL verify your LCAL value Command S 41 114 Response Restore Calibrator Level Here are typical Calibration Offset Levels dB for several acceler...

Page 431: ...used with the AUDit software However the System 824 with 824 AUD firmware alone still possesses numerous analysis features useful for audiom eter testing tasks such as Level Frequency Linearity Total...

Page 432: ...rted into the opening on the side of the artificial ear base and threaded into place A microphone extension cable connects the microphone preamplifier to the input of the System 824 One of the audiome...

Page 433: ...er testing firmware option turn on the 824 After the start screen is appears press S SETUP and use the arrow keys up down arrows ud to highlight the AudTest AUD setup or your customized AUD setup Pres...

Page 434: ...frequency At this time the instrument should be calibrated manually Press the Tools key T use the down darrow key to highlight Calibration press the check key c twice use the down darrow key to highl...

Page 435: ...ccessed by pressing the up uand down darrow keys View Menu The structure of the View menu is described below Press the VIEW key V to open the View Menu SLM RTA Submenu Highlighting SLM RTA and pressin...

Page 436: ...page 25 for details on this display type SLM RTA Live Any Level a Any Level b Linearity RTA Linearity FFT activated by default when AUD is activated Flatness FFT THD Pulse FM SLM RTA Live Display The...

Page 437: ...f the linearity displays step between 0 and 30 dB gain if the gain setting is something other than 0 or 30 the AGC function is inhibited RTA Detector This setting controls the rate of change of RTA fi...

Page 438: ...h the non test earphone being measured then comparing the test earphone level to that measurement Any Level a b and c Displays The Any Level Displays a b and c are accessed from the SLM RTA Live displ...

Page 439: ...ing Use the right and left arrow keys to step between the a b and c displays Press the check key c to access the check menu shown below Any Level Check Menu The Any Level check menu items are Gain Cha...

Page 440: ...wn are the filter frequency of the selected level and the RTA Bandwidth setting The frequency weighting set by the RTA Weighting setting is used Flat by default For testing attenuator linearity at 1 k...

Page 441: ...lock to the desired filter frequency when going to low amplitudes when other noise signals ambient noises or vibrations present in the environment may be higher than the signal being output by the aud...

Page 442: ...ow amplitudes AGC is not active in the manual unlock or lock modes Automatic Lock For automatic operations select the auto mode by pressing the left or right arrow key until the diamond icon appears a...

Page 443: ...vel for 1 5 seconds When the gain is set to 30dB the gain will be changed to 0dB whenever the instrument becomes overloaded or the level is within 8dB of the overload level for 1 5 seconds The instrum...

Page 444: ...wn in View Menu on page 13 5 The Linearity FFT display shown below is accessed from the Linearity RTA display by pressing the down arrow key dto produce the display shown below The Linearity FFT displ...

Page 445: ...the Reference Lvl setting on the check menu This zero level may be set at the 70dB HL point as a reference Once the reference has been set the level is shown relative to the reference level as shown...

Page 446: ...active in the manual unlock or lock modes Automatic Lock For automatic operations select the auto mode by pressing the left or right arrow key until the diamond icon appears A trigger level setting i...

Page 447: ...ment Generally use 0dB gain for levels at 70dB SPL and above and 30dB gain for levels less than 70dB SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gain if t...

Page 448: ...the FFT data and the THD plus noise metric The frequency weighting for this display is forced to Flat regardless of the Weighting setting This display is used to measure the frequency response of an a...

Page 449: ...ental frequency and harmonics THD data is output in dB down from the fundamental level and in percent The display also shows the level and frequency of the fundamental An asterisk following a THD perc...

Page 450: ...ed by summing the energy of the fundamental bin with the five bins on each side then subtracting the energy sum of all the other levels The THD as calculated in the 824 satisfies all of the requiremen...

Page 451: ...instrument Generally use 0dB gain for levels at 70dB SPL and above and 30dB gain for levels less than 70dB SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gai...

Page 452: ...STOP key s The stability of the measurement can be evaluated visually To retrieve data press RUN STOP again s and read the values from the screen The following values are displayed rise time fall time...

Page 453: ...e F J time in milliseconds between successive 5 dB points of the envelope of the pulsed signal during which the signal is absent nominally between 190 and 260 ms Plateau or Pulse Width C E duration in...

Page 454: ...press the RUN STOP key s When the stable message is displayed as shown below press RUN STOP s again and read the values from the screen The following values are displayed all in units of Hz Carrier f...

Page 455: ...o be activated from the THD check menu The right and left arrow keys control the frequency cursor and the up and down arrow keys control the display horizontal zoom feature FFT Check Menu Press the ch...

Page 456: ...ault value is A weighting so that the Linearity FFT display has the greatest noise rejection The Flatness FFT display overrides this setting and forces the electronics to be Flat weighted Note The Lin...

Page 457: ...trol The System 824 is fully controllable remotely via the Serial Port interface Settings and the operational mode can be changed by sending commands through the serial port Data can also be downloade...

Page 458: ...ious interface commands with their syntax Modem control is also covered Command text files and programming examples are available upon request via email to techsupport LarsonDavis com Interface Cables...

Page 459: ...6 with the wrap around label are slightly different as CBL006 824 to computer cable 9 pin female D CBL002 824 to serial printer 25 pin male D CBL003 824 to modem cable 25 pin male D CBL091 824 to HP L...

Page 460: ...A 4 824 Reference Manual 9 29 09 shown below Both versions work properly with the Model 824...

Page 461: ...s a single byte ranging in value from 129 to 228 representing address 1 to 100 respectively address plus 128 while addresses 101 through 127 are reserved At power on all 824s are address enabled as if...

Page 462: ...ssing of all 824s on the net in a broadcast receive mode Only the 824 with address 1 will respond all will receive the command 127 Address 127 FF Address All will enable all 824s to receive and respon...

Page 463: ...addressing may be changed break break Two breaks in a row will re initialize the I O and Printer tasks and the clear the data and command buffers It will also address all instruments first command sho...

Page 464: ...ponse to acknowledge that it was received correctly and to provide data requested For high reliability systems there is an error checking protocol that will ensure proper command data transferal See E...

Page 465: ...vel without accumulating data M6 or M6 0 Set standard mark M6 1 Set mark 1 Aircraft M6 2 Set mark 2 Automobile M6 3 Set mark 3 Truck M6 4 Set mark 4 Train M6 5 Set mark 5 Animal M7 or M7 0 Reset curre...

Page 466: ...1 Lock 824 and Power Off cease sending further commands M 12 Disconnect Modem terminate connection and hang up M 13 Extend Modem Connect Time out can be set up to 255 seconds and allows time for modem...

Page 467: ...ilters F1 and 1 1 plus 1 3 octave filters F3 The Environmental noise analyzer option is either present E1 or not E0 The memory has 4 options Standard 1 2 megabyte M0 1 megabyte M1 1 5 mega byte M2 and...

Page 468: ...e instrument Lock Status and is either an L or a U The fourth character is the Logic Input Status and is a 1 if high and a 0 if low The fifth character will be an a if an Alarm has been detected other...

Page 469: ...urrent SPL nnn nn dB R5 ALL OverAll Runtime hhhhh mm ss s R6 ALL OverAll Start Date and Time ddmmmyy hh mm ss R7 ALL Current Runtime hhhhh mm ss s R8 ALL Current Start Date and Time ddmmmyy hh mm ss R...

Page 470: ...G OverAll Lpeak Date and Time ddmmmyy hh mm ss R25 w SSA ISM LOG Current Peak Level nnn n dB R 26 w SSA ISM LOG Current Lpeak Date and Time ddmmmyy hh mm ss R27 w LOG OverAll UWPk Level Peak Level 1 n...

Page 471: ...nnn n R47 SSA ISM LOG Current Projected Dose nnnnn n R54 ALL Last Level Relative to REFLVL nnn n R55 LOG Display Histogram Selected ccc R 56 LOG Display Total Counts in Ln Table nnnnnk R 57 LOG Overal...

Page 472: ...und Leq nnn n dB R86 ALL Battery Level nnn R87 ALL Battery Source INT EXT ccc R88 ALL Temperature nnn n R89 ALL Serial Number ccccc R90 ALL Firmware Rev Rev Date n nnn ddmmmyyyy R91 ALL Free Memory nn...

Page 473: ...Flag 1 R109 SSA ISM LOG RMS Exceedance Flag 2 R110 SSA ISM LOG PEAK Exceedance Flag R111 SSA ISM LOG UWPK Exceedance Flag R112 ALL System Overload Flag R113 LOG Excd Exchange Rate Text ccccc R114 LOG...

Page 474: ...n dB R141 SSA LOG Interval SEL nnn n dB R142 SSA LOG Interval Lmin nnn n dB R143 SSA LOG Interval Lmax nnn n dB R144 SSA LOG Interval Lpeak nnn n dB R145 SSA LOG Interval UnWeighted Peak nnn n dB R146...

Page 475: ...event the loss of keys nnn R156 LOG Background Leq Time hhhhh mm ss ss R157 ALL Calibration Status Done Wait Waiting Stable Unstable Too High Too Low R158 ALL Total Memory Available nnnnnn R159 ALL Me...

Page 476: ...pascal squared R163 x SSA ISM LOG TAKT 3 nnn n dB R164 x SSA ISM LOG TAKT 5 nnn n dB R165 LOG PassBy Time of Occurrence ddmmmyy hh mm ss R166 LOG PassBy Event Duration hh mm ss mm ss ss R167 LOG Pass...

Page 477: ...Number Revision Date n nnn ddmmmyyyy R188 SSA RTA Spectra at Lmax nnn n dB R189 ALL Logic Input State On or off R190 ALL Noise Floor Indicators c or cccc flags R191 AUD Audiometric Test Rise Time nnnn...

Page 478: ...n n R208 RTA Live Spectrum s Duration s ssss R209 RTA Live Spectrum s Overload Status Ovld R210 f RTA Leq Spectrum f ANSI filter num ber or 1 for Flat nnn n R211 RTA Leq Spectrum s Duration hhhhh mm h...

Page 479: ...ccccc R226 n ALL Display the Last history record type 0 Last record type string 1 Date Time of last record 2 Duration Runtime of last rec 3 Record Size bytes 4 Instrument type of record ccccccccc ddm...

Page 480: ...tion fre quency see following commands R241 512 AUD FFT Extract harmonic distortion data from FFT Live no output data R241 1024 AUD FFT Extract harmonic distortion data from FFT Snapshot no output dat...

Page 481: ...ng the second operand indicated R241 n 1024 AUD FFT Show noise floor influence indicator for harmonic n n 1 to 20 valleys have less than 10 dB from har monic if no influence if influence detected R242...

Page 482: ...um Level Any Wght Dect nnn n dB R 20 x SSA ISM LOG OverAll Lmax Date and Time Any Wght Dect ddmmmyy hh mm ss R 21 x SSA ISM LOG Current Maximum Level Any Wght Dect nnn n dB R 22 x SSA ISM LOG Current...

Page 483: ...or is not applica ble for Takt levels Where w indicates a number to represent the weighting which has these values Detector is not applicable for these measurements 1 A weight Slow detector 2 A weight...

Page 484: ...n Response O 1 Read SLM data nnn n nnn n nnn n nnn n CR LF R 4 SPL R 11 TWA R 17 Lmin R 21 Lmax CR LF O 2 Read Wind Data nnn n ccc nnn n nnn n ccc CR LF O 3 Read Group of R vari ables programmed by th...

Page 485: ...variable and its position in the macro O 8 AUD FFT Read THD data Fund Frequency Fund Level THD n 2nd 3rd 4th 5th and above nnnnnn nnn n n nn n nn n nn n nn O 9 AUD FFT Read Fund Frequency and Fund Le...

Page 486: ...oup read list the response to G0 is 59 5 38 6 102 2 the SPL Lmin and Lmax Setting Commands The Settings select what functions are enabled and determine how the measurements are performed Settings can...

Page 487: ...and options is a number to select the appearance of the response Brackets indicate optional characters or operands cr carriage return lf line feed _ space Option flags elicit the following responses...

Page 488: ...32 824 Reference Manual 9 29 09 Flag values may be added together for desired combinations Example Response 1 Q74 No 2 Q74 1 Excd History Enable No 3 Q74 2 _No 4 Q74 32 0 5 Q74 3 Excd History Enable _...

Page 489: ...here setting_number is the setting number setting_value is the desired setting and option_text is the textual setting for the option settings those that have one setting from a list of possible settin...

Page 490: ...lon and enclosed by brackets Option settings text must include the same number of characters that are given when queried including spaces which are indicated below with __ Syntax Response S et item_nu...

Page 491: ...t ASCII 96 or hexadecimal 60 Example S74 Yes sets Excd History Enable to Yes Example S95 _1 32s sets Hist Period Units to 1 32s Example S95 _1 0s sets Hist Period Units to 1 0s Syntax Response S et it...

Page 492: ...lly or in year month and date for ISO 8601 format ddmmmyyyy or yyyymmmdd Times are entered in hour minutes and seconds order and are separated by 24 hour clock time is used i e hours 0 to 23 Syntax Re...

Page 493: ...EEK S9 x ALL Serial Communications Baud Rate S10 n ALL Serial Communications Address S11 x ALL Serial Communications Output Flow Control S12 x ALL Printer Serial Bit Rate S13 x ALL Printer Serial Outp...

Page 494: ...nn 0 to 99 minutes S23 ALL Auto Off Time nn 0 to 99 minutes S24 ALL Backlight Power Off Time nn 0 to 99 seconds S25 ALL Backlight On Off S26 ALL LCD Contrast 0 to 99 nn S27 SSA LOG TIMER MODE S28 SSA...

Page 495: ...1 S49 SSA ISM LOG AUD Pk Detector Weighting A C Flat S50 SSA ISM LOG RANGE Normal Low High S51 ALL Transducer Type Air Condenser Elec tret Direct S52 SSA ISM LOG AUD Simple SLM Displayed Value S53 SSA...

Page 496: ...CRITERION TIME HOURS S59 RTA RTAf AUTOMATICALLY STORE EVENT RECORDS YES NO S60 LOG LDL EXCHANGE RATE S60 RTA RTAf ENABLE EVENT BYTIME HISTORY NO YES S61 LOG LDL THRESHOLD S61 RTA RTAf EVENT BYTIME PR...

Page 497: ...nce Level 1 S69 RTA RTAf TRIGGER MODE NOW L L L INPUT TIME COUNT S70 SSA ISM LOG SPL Exceedance Level 2 S70 RTA RTAf TRIGGER LEVEL NNN N dB S71 SSA ISM LOG Peak II Exceedance Level S71 RTA RTAf TRIGGE...

Page 498: ...f END TIME SS SSSS SECONDS S79 RTA RTAf END SAMPLES NNNNN S80 LOG EXCD Passby Trigger Mode S80 RTA RTAf END LOGIC INPUT TRUE LEVEL LOW HIGH S81 LOG EXCD Occurrence Time Start Max S81 RTA RTAf END THEN...

Page 499: ...S88 LOG INTV SAVE Ln S S90 SSA LOG INTV AUTO STOP S91 LOG ENABLE TIME HIST S92 LOG TIME HISTORY RESOLUTION S93 LOG Other TIME HISTORY Level S94 LOG TIME HISTORY PERIOD S95 LOG TIME HISTORY PERIOD UNI...

Page 500: ...bins this corresponds to 1 8th dB resolution for RMS and 1dB resolution for the peak tables S104 LOG SPL HISTOGRAM TABLE x S105 LOG SPL HISTOGRAM TABLE LOW VALUE n S106 LOG SPL HISTOGRAM TABLE HI VAL...

Page 501: ...Mode SLM RTA FFT Pulse FM S144 FFT FFT Lines 100 200 400 S145 AUD FFT FFT Bandwidth 200 to 20KHz S146 FFT FFT Averaging Count 1 to 65535 S147 AUD FFT FFT Window Type Rectangular Hanning S148 SSA RTA...

Page 502: ...re not available on SETUP menu S159 166 Reserved settings S167 ALL RELATIVE LEVEL REFERENCE S174 ALL UNFORMATTED REPORTS x S175 Reserved setting S176 ALL PRINTER TYPE x S177 ALL DATA REPORT x S178 SSA...

Page 503: ...S189 RTA RTAf PRINT LEQ SUMMARY OR EVENT DATA NO YES S190 LOG PEAK I HISTOGRAM TABLE HI VALUE n S190 RTA RTAf PRINT MAX SUMMARY OR EVENT DATA NO YES S191 LOG PEAK I HISTOGRAM TABLE RESOL x S191 RTA RT...

Page 504: ...and is sent S196 SSA ISM LOG INTV REPORT LOWEST RECORD n S197 SSA ISM LOG INTV REPORT HIGHEST RECORD n S198 LOG HIST REPORT x S199 LOG HIST REPORT LOWEST RECORD n S199 RTA EVENT BYTIME REPORT LOW EST...

Page 505: ...d Linearity Range Mode The true noise floor of the entire system must be measured and entered in Q207 This will vary with the selected input weighting or microphone sensitivity An equivalent microphon...

Page 506: ...ALL Graph Vertical Scale dB per pixel S220 ALL Graph Base Level range from 99 to 999 S221 ALL Request to send Output Control Mode S224 LOG RTA Start Level nn for Ln and ExTH S227 ALL OVERALL CALIBRAT...

Page 507: ...RTA Event By Time Pretrigger Samples nnn S60 RTA Event Triggering Enable No Yes S61 RTA Trigger Source Level 12 5 16 0 16 0K 20 0K Flat Hz S62 RTA Store By Time Samples of Event No Yes S63 RTA Arm Mo...

Page 508: ...End Level nnn n dB S78 RTA End Time ss ssss Sec S79 RTA End Samples nnnnn S80 RTA End Logic Input TRUE Level Low High S81 RTA End Then Repeat Mode Stop Repeat Average S82 RTA Repeat Count nnn 0 to 25...

Page 509: ...No Short Long S199 RTA Event ByTime REPORT LOWEST RECORD nnnnn S200 RTA Event ByTime REPORT HIGHEST RECORD nnnnn S213 RTA ByTime History Record nnnnn S195 RTA Spatial Average History Report Enable S20...

Page 510: ...the 1 specifies that it is an Exceedance record to be found as defined in the history_number column below The Advance and Backup commands are generally used next They extract data after the initial f...

Page 511: ...nd Find commands and is shown below Denoted in syntax by history_number 1 Exceedance E 2 Interval I 3 Daily D 4 Run Log L 5 Calibration C 6 Time H 7 Histogram Table T Advance Advance a number of recor...

Page 512: ...cord number directly Syntax Response B ackup num_record history_number cr lf Example B Example B5 Example B9 5 Backup current history by 1 record Backup current history by 5 records Backup the calibra...

Page 513: ...tional characters and operands Syntax Response E xceedance var_no Excd_var Example E9 __2 Overload count from current record Commands Instrument Type Description Commnet E1 LOG RTA Date and Time of Oc...

Page 514: ...rt current sample E12 f RTA By Time Sample Filter Level E13 n RTA ByTime Sample Time E14 n RTA By Time Sample Duration E15 n RTA By Time Overload E16 RTA RT60 calculation at current filter Filter set...

Page 515: ...from one second up to 99 hours 59 minutes and 59 seconds 99 59 59 Brackets in the syntax indicate optional characters and operands E21 n LOG Excd T H Bargraph E101 LOG Excd Macro Variables 1 10 25 Ma...

Page 516: ...All subsequent intervals will now be synchronized to the real time clock Intv Period Sync On Sync to nearest 01 00 hh 00 hour 00 30 hh 00 hh 30 half hour 30 minutes 00 20 hh 00 hh 20 hh 40 one third h...

Page 517: ...Mode SLM RTA Tonal I5 SSA LOG Lmin nnn n dB I5 n FFT FFT Line Level n 0 to 400 nnn n I5 n RTA RTA Live Spectrum Level nnn n dB I6 n RTA RTA Leq Spectrum Level nnn n dB I6 SSA LOG Lmax nnn n dB I7 SSA...

Page 518: ...1 LOG Intv Ln 5 Percent nn I22 LOG Intv Ln 5 Level dB nnn n I23 LOG Intv Ln 6 Percent nn I24 LOG Intv Ln 6 Level dB nnn n I37 n SSA RTA Filter Leq n ANSI filter nnn n dB I38 n SSA RTA Filter Leq n ANS...

Page 519: ...ercent nn I15 SSA LOG Intv Ln 3 Level dB nnn n I16 SSA LOG Intv Ln 4 Percent nn I17 SSA LOG Intv Ln 4 Level dB nnn n I18 SSA LOG Intv Ln 5 Percent nn I19 SSA LOG Intv Ln 5 Level dB nnn n I20 SSA LOG I...

Page 520: ..._var Example D5 5 hourly noise level for hour 5 to 5 59 59 a m D 1 LOG Date ddd ddmmmyyyy D 2 LOG Daily Leq nnn n dB D 3 LOG Daily LDN nnn n dB D 4 LOG Daily CNEL nnn n dB D 5 hn LOG HNL for hour 0 23...

Page 521: ...D 24 LOG Intv Ln 3 Percent nn D 25 LOG Intv Ln 3Level dB nnn n D 26 LOG Intv Ln 4 Percent nn D 27 LOG Intv Ln 4 Level dB nnn n D 28 LOG Intv Ln 5 Percent nn D 29 LOG Intv Ln 5 Level dB nnn n D 30 LOG...

Page 522: ...Run Stop Type RUN STOP CONT PAUSE MARK L 3 Cause TIMER KEY A D n HALT INTV BATT L 4 Day Date and Time ddd ddmmmyyyy hh mm ss L 101 Run Log Macro Variables L1 L5 Macro Syntax Response C alibration var_...

Page 523: ...levels The optional parameter n is available only when advanced time history is enabled When n is omitted or 0 all enabled values are transmitted H 6 n SSA LOG TAL Return descriptive text for the adv...

Page 524: ...e optional characters and operands Histogram Table Variables Brackets in the syntax indicate optional characters and operands Table 1 RMS 2 Peak 3 Unweighted Peak Default is last used table or RMS Syn...

Page 525: ...n LOG Count of samples nnnnnc c K or M for Kilo or Mega T 3 n LOG Percent of total nnn nn T 5 n LOG Prints the accumulated time for the current level bin The table number is optional hhhhh mm ss s T...

Page 526: ...9 113 P 1 ISM SSA LOG RTA Data Report P 2 SSA LOG Data Histograms P 3 SSA LOG Short Full Report Histories with SHORT option P 4 SSA LOG Long Full Report Histories with LONG option P 9 ISM SSA LOG RTA...

Page 527: ...n a spreadsheet program Also use this to download reports for printing on a computer s printer rather than directly from the 824 this lets reports to be printed on a nice laser printer connected to a...

Page 528: ...30 Battery Low 131 POWER FAILURE 132 External Power Failure 133 Power Off 134 Time Not Set 135 Timer Pending 136 Printer is Busy 137 DPC Format 138 Key No Effect 139 Stop Required 140 Setting Wrong 14...

Page 529: ...Serial Port Line Noisy 157 Serial Port Over Run 158 Unknown I O Command 159 Operand 1 Range 160 Operand 2 Range 161 I O Overflow 162 Can t Calibrate 163 Calibration Invalid 164 Analog Calibration Bad...

Page 530: ...respond to commands using numeric codes non verboses Modem Mode If the Modem Mode is Yes the Model 824 will dial the Phone on the events selected by the Dial Out Mode defined below Dial Out Mode None...

Page 531: ...dem sends 824A0123 001 2 Enter Step 3 The modem informs the Model 824 that a connec tion has been made The Model 824 modifies its baud rate to that of the connected modem If the connection is unsucces...

Page 532: ...cause the Model 824 to hang up 824 sends Ready Step 6 When a correct response is received the Model 824 indicates it is ready to send data when requested with 824 Ready enter Model 824 Answering Proc...

Page 533: ...ere 0123 is the Model 824 s serial number and 11111111 is the Lock Combination setting 28 which is required whether or not the Model 824 is currently locked If the response is incorrect the announceme...

Page 534: ...ta dump x bit flags Add 1 to x to automatically reset histories at completion of transfer Add 2 to x to inhibit the pause just before sending OverAll data the pause provides for cohesive data Add 4 to...

Page 535: ...SPL graph A delimiter byte ASCII 212 in decimal which is the letter T with 128 added to it precedes the time string Full resolution including the fractional part of the level is sent if enabled by the...

Page 536: ...elimiter following the K is required before non numeric operands i e K 6 The keyboard buffer will hold up to 8 keys K12345678 is acceptable F101 Read macro F variables 1 through 8 F102 Recall a FILE i...

Page 537: ...the line is Low no data is taken The Pause mode will pause the data taking process while the line is high this may be triggered by high wind speed In the Toggle mode when the Logic Input line goes hig...

Page 538: ...A 82 824 Reference Manual 9 29 09...

Page 539: ...sound pressure level also average A weighted sound pressure level is defined as follows where LAeq T is the equivalent continuous A weighted sound pres sure level re 20 Pa determined over a time inter...

Page 540: ...ubling rates can be entered that effect certain TWA measurements Certain TWA measurements include a programmable thresh old with only levels above this threshold contributing to the measurement The ti...

Page 541: ...ample The System 824 s Logging SLM Overall e display shows the overall measurement period and TWA In this case the measurement is Leq because of the 3dB exchange rate The quantity is A weighted and ha...

Page 542: ...mple rate is 32 samples per second and Lcal is the calibration offset that corrects for various sensitiv ities of microphones Accuracy is maintained by having large fixed point variables for the numbe...

Page 543: ...the Threshold and Exchange Rate settings Care should be taken when modifying these settings since some standards or govern ments require SEL to be taken without a Threshold set it to zero and with an...

Page 544: ...the exchange rate where q 10 for a 3dB exchange rate q 5 log 2 for a 5dB exchange rate q 4 log 2 for a 4dB exchange rate The factor of 100 in the equation produces a result that is a percentage Dose i...

Page 545: ...te times 32 samples sec equals 115200 sam ples second LC is the criterion sound level as set by the System 824 s Overall Criterion or Current Criterion settings Addition of the term log 100 was used t...

Page 546: ...B 8 824 Reference Manual 9 29 09...

Page 547: ...g an ADP005 microphoneadapter 18pF These specifications are valid for all System 824 s using the following options PRM902 preamplifier 377B41 or 377A60 free field or random high sensi tivity microphon...

Page 548: ...cable CBL042 AC DC output cable CBL006 serial interface cable is in accordance with the following directives 89 336 EEC The Electromagnetic Compatibility Direc tive and its amending directives has be...

Page 549: ...Ln statistics L0 01 through L99 9 available Histogram tables Direct report printouts to laser printer WindowsTM based software for setup control and high speed data download and reporting Advanced Win...

Page 550: ...n arrowd key and highlight Change Press the check c key to initiate the calibration The 824 will prompt you to turn the calibrator on with Calibrator Active Select Yes after turning the calibrator on...

Page 551: ...tput loading AC DC output con nector 3 5mm stereo jack Power Supply Batteries 3 AA alkaline cells or NiMH battery pack Internal charge time approx 7 10 hours BAT010 2300 mAH pack approx 6 hours BAT010...

Page 552: ...hours 4 5 hours Standard Alkaline AA eg Duracell MN1500 type LR6 4 3 hours 2 8 hours High Drain Rate Alkaline AA e g Duracell Ultra MX1500 type LR6 4 4 hours 4 4 hours Photo Lithium AA e g Energizer e...

Page 553: ...S all other instruments 0 1 second Real time clock 1 second Calendar 01 Jan 2000 31 Dec 2099 Cable Drive Capability with PRM902 preamp Frequencies to 20 kHz 700 feet 213 meters Frequencies to 10 kHz 1...

Page 554: ...19 1 0 3 0 1 0 1 0 0 0 5 0 5 125 125 00 16 1 0 2 0 0 0 0 0 0 0 5 0 5 160 158 50 13 4 0 1 0 0 0 0 0 0 0 5 0 5 200 199 50 10 9 0 0 0 0 0 0 0 0 0 5 0 5 250 251 20 8 6 0 0 0 0 0 0 0 0 0 5 0 5 315 316 20 6...

Page 555: ...ifications Time weighting Slow Fast Impulse TWA and Peak Frequency Weightings A C and Flat see table on page C 7 Dynamic range 115 dBA Overload to noise floor Linearity range 105 dBA Pulse range 108 d...

Page 556: ...additional 20 dB of gain AC DC Output LOG and ISM modes only 824 Menu 3 5mm Connector Tip 3 5 mm Connector Ring AC 1 AC 2 Flat AC output Flat AC output with 30dB gain AC 1 DC Flat AC output Weighted D...

Page 557: ...Limit High Limit Range Pulse Range A WT high 22 43 151 108 108 A WT normal 12 23 131 108 108 A WT low 10 20 111 91 91 C WT high 38 48 151 103 103 C WT normal 18 28 131 103 103 C WT low 14 25 111 86 8...

Page 558: ...73 148 75 A WT normal 53 0 128 0 75 0 A WT low 53 0 108 0 55 0 C WT high 73 148 75 C WT normal 53 0 128 0 75 0 C WT low 53 0 108 0 55 0 FLAT high 80 148 68 FLAT normal 60 0 128 0 68 0 FLAT low 60 0 1...

Page 559: ...ing 75 dB Summation of output signals 1 0 dB 0 4 dB typical Flat frequency range 10 Hz 20 kHz relative attenuation 0 15 dB Filter type Digital Octave frequency ratio Base 2 See IEC 61260 Annex A AC DC...

Page 560: ...35 118 83 1 23 108 85 2 25 98 73 4 22 88 66 4 23 78 55 63 0 4 40 128 88 0 33 118 85 1 23 108 85 0 22 98 76 7 15 88 73 7 18 78 60 125 2 40 128 88 2 27 118 91 3 28 108 80 2 18 98 80 9 11 88 77 8 8 78 7...

Page 561: ...putation After the ON state has been detected the ON level is computed as the average of 32 samples Overshoot computation Overshoot is calculated as the maximum sample level minus the averaged ON leve...

Page 562: ...eraging Count Window Rectangular or Hanning Linearity range 85 dB with Hanning window 20 kHz bandwidth and PRM902 Dynamic range Flat SPL linearity range 100 dB 75 dB Bandwidth Hz Bin 0 2 dB 20 000 50...

Page 563: ...0 0 21 1 0 4 125 125 00 0 0 18 1 0 2 160 158 50 0 0 15 3 0 1 200 199 50 0 0 12 8 0 1 250 251 20 0 0 10 6 0 1 315 316 20 0 0 8 6 0 0 400 398 10 0 0 6 7 0 0 500 501 20 0 0 5 2 0 0 630 631 00 0 0 3 8 0 0...

Page 564: ...5 dB 1 1 octave Reference level range 0 dB gain Sample rate 51 200 Hz 1 3 octave band frequencies 12 5 Hz 20 kHz 33 filters 1 1 octave band frequencies 16 Hz 16 kHz 11 octaves Filter integrated respon...

Page 565: ...8 88 80 9 8 78 70 500 12 33 128 95 4 25 118 93 3 15 108 93 4 13 98 85 10 6 88 82 10 8 78 70 1000 10 32 128 96 2 20 118 98 4 15 108 93 5 13 98 85 10 6 88 82 10 8 78 70 2000 15 32 128 96 6 20 118 98 2...

Page 566: ...signal is 1 Volt rms at 1 kHz Frequency Range 1 1 Octave Filters 16 Hz to 16 kHz 1 3 Octave Filters 12 5 Hz to 20 kHz Filter Shapes Filters are characterized by the shape of their filter skirts and t...

Page 567: ...igure 13 3 Filter Skirts of 1kHz 1 3 Octave Filter 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90 00 100 00 110 00 120 00 130 00 0 1 1 10 Relative Frequency amplitude dB 1000 Hz Filter Skirts IEC...

Page 568: ...nd with the arm extended away from the body Better results can be obtained by using a tripod Effect of Windscreen The Corrections which should be subtracted from the measured data when using the Larso...

Page 569: ...9 29 09 C 23 Windscreen Response with Respect to No Windscreen...

Page 570: ...digital filter is added which gives the necessary correction to provide random incidence response when measuring with a free field microphone NOTE Tested with the preamplifier and microphone attached...

Page 571: ...Graph 1 The 824 in normal range with the 2540 free field microphone showing the uncorrected random response Graph 2 The 824 in normal range with the 2540 free field microphone showing the corrected ra...

Page 572: ...9 29 09 Graph 3 The 824 in normal range with the 377B41 free field microphone showing the uncorrected random response Graph 4 The 824 in normal range with the 377B41 free field microphone showing the...

Page 573: ...he 824 in normal range with the 2551 free field electret microphone showing the uncorrected random response Graph 6 The 824 in normal range with the 2551 free field electret microphone showing the cor...

Page 574: ...wing random response with the random corrector Microphone Response Tests with 824 The 824 was oriented with the LCD facing up for these tests The following graphs show the effects on the performance o...

Page 575: ...9 29 09 C 29 Graph 1 The 824 in normal range with the 2540 microphone Graph 2 The 824 in normal range with the 2540 microphone and windscreen...

Page 576: ...C 30 824 Reference Manual 9 29 09 Graph 3 The 824 in high range with the 2540 microphone Graph 4 The 824 in high range with the 2540 microphone and windscreen...

Page 577: ...9 29 09 C 31 Graph 5 The 824 in normal range with the 377B41 microphone Graph 6 The 824 in normal range with the 377B41 microphone and windscreen...

Page 578: ...C 32 824 Reference Manual 9 29 09 Graph 7 The 824 in high range with the 377B41 microphone and windscreen Graph 8 The 824 in normal range with the 2551 free field microphone...

Page 579: ...824 with the 2540 377B41 and 2551 free field microphones Test Setup The 824 was tested in two different configurations as fol lows 824 oriented with the LCD facing up 824 oriented on it s side Defini...

Page 580: ...C 34 824 Reference Manual 9 29 09 Graph 1 824 in the XY plane fitted with the 2540 microphone 1 kHz Graph 2 824 in the XY plane fitted with the 2540 microphone 2kHz...

Page 581: ...9 29 09 C 35 Graph 3 824 in the XY plane fitted with the 2540 microphone 4 kHz Graph 4 824 in the XY plane fitted with the 2540 microphone 8 kHz...

Page 582: ...C 36 824 Reference Manual 9 29 09 Graph 5 824 in the XY plane fitted with the 2540 microphone 12 5 kHz Graph 6 824 in the YZ plane fitted with the 2540 microphone 1 kHz...

Page 583: ...9 29 09 C 37 Graph 7 824 in the YZ plane fitted with the 2540 microphone 2 kHz Graph 8 824 in the YZ plane fitted with the 2540 microphone 4 kHz...

Page 584: ...C 38 824 Reference Manual 9 29 09 Graph 9 824 in the YZ plane fitted with the 2540 microphone 8 kHz Graph 10 824 in the YZ plane fitted with the 2540 microphone 12 5 kHz...

Page 585: ...9 29 09 C 39 Graph 11 824 in the XY plane fitted with the 377B41377B41 microphone 1 kHz Graph 12 824 in the XY plane fitted with the 377B41 microphone 2 kHz...

Page 586: ...C 40 824 Reference Manual 9 29 09 Graph 13 824 in the XY plane fitted with the 377B41 microphone 4 kHz Graph 14 824 in the XY plane fitted with the 377B41 microphone 8 kHz...

Page 587: ...9 29 09 C 41 Graph 15 824 in the XY plane fitted with the 377B41 microphone 12 5 kHz Graph 16 824 in the YZ plane fitted with the 377B41 microphone 1 kHz...

Page 588: ...C 42 824 Reference Manual 9 29 09 Graph 17 824 in the YZ plane fitted with the 377B41 microphone 2 kHz Graph 18 824 in the YZ plane fitted with the 377B41 microphone 4 kHz...

Page 589: ...9 29 09 C 43 Graph 19 824 in the YZ plane fitted with the 2551 microphone 8 kHz Graph 20 824 in the YZ plane fitted with the 377B41 microphone 12 5 kHz...

Page 590: ...C 44 824 Reference Manual 9 29 09 Graph 21 824 in the XY plane fitted with the 2551 microphone 1 kHz Graph 22 824 in the XY plane fitted with the 2551 microphone 2 kHz...

Page 591: ...9 29 09 C 45 Graph 23 824 in the XY plane fitted with the 2551 microphone 4 kHz Graph 24 824 in the XY plane fitted with the 2551 microphone 8 kHz...

Page 592: ...C 46 824 Reference Manual 9 29 09 Graph 25 824 in the XY plane fitted with the 2551 microphone 12 5 kHz Graph 26 824 in the YZ plane fitted with the 2551 microphone 1 kHz...

Page 593: ...9 29 09 C 47 Graph 27 824 in the YZ plane fitted with the 2551 microphone 2 kHz Graph 28 824 in the YZ plane fitted with the 2551 microphone 4 kHz...

Page 594: ...C 48 824 Reference Manual 9 29 09 Graph 29 824 in the YZ plane fitted with the 2551 microphone 8 kHz Graph 30 824 in the YZ plane fitted with the 2551 microphone 12 5 kHz...

Page 595: ...ging 0 012 W 0 96 W 1 28 W 1 73 W 1 72 W 2 21 W Power Charging N A 2 25 W 2 53 W 3 05 W 3 00 W 3 50 W 15 V 0 9 mA 65 mA 85 mA 118 mA 116 mA 150 mA 12 V 1 1 mA 80 mA 107 mA 144 mA 143 mA 184 mA Current...

Page 596: ...C 50 824 Reference Manual 9 29 09...

Page 597: ...allowed time of exposure to sound of a constant A weighted sound level given a chosen Criterion Level Criterion Duration and Exchange Rate The equation for it is where Lc is the Criterion Level Tc is...

Page 598: ...s above the Threshold Level are included in the integral Standard ANSI S12 19 Community Noise Equivalent Level CNEL Lden A rating of community noise exposure to all sources of sound that differentiate...

Page 599: ...is expressed in Pascals squared seconds when the exchange rate is 3 dB where q is the Exchange Rate Factor See Exchange Rate Standard ANSI S1 25 Criterion Sound Level Lc It is the sound level which if...

Page 600: ...age noise exposure rating Decibel dB A logarithmic form of any measured physical quantity and commonly used in the measurement of sound and vibration Whenever the word level is used this logarithmic f...

Page 601: ...ty to an actual reference quantity used Thus for every level in decibels there must be a well defined reference quantity Sound versus vibration uses different references but the dB principal is the sa...

Page 602: ...that a doubling of the sound power is equal to 3 dB and a doubling of the sound pressure is equal to 6 dB since a doubling of the sound pressure will result in a quadruple increase of the sound power...

Page 603: ...trates how a a tenfold increase of the sound pressure will result in an increase in 20 dB steps while sound power increases in 10 dB steps See the linear form Table 2 and compare with equation D 1 In...

Page 604: ...t sound level that would expose a person to the same Noise Dose as the actual unsteady sound levels The equation for it is NOTE This definition applies only for a Criterion Duration of 8 hours Standar...

Page 605: ...source of sound is greater than the largest dimension of the sound source In the far field the effect of source geometry is negligible Sound sources often have a variety of specific sources within th...

Page 606: ...quencies Bandpass A frequency filter that permits signals to pass through that have frequencies above a certain fixed frequency called a lower cutoff frequency and below a certain fixed frequency call...

Page 607: ...om used See table below C Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to high levels of sound This weighting is most often used f...

Page 608: ...It applies to hearing damage risk and is generally expressed in hours Standard ANSI S12 19 Microphone Guidelines Microphone Types A device for detecting the presence of sound Most often it converts t...

Page 609: ...ed to have an essentially flat frequency response for sound waves impinging on the microphone from all directions Pressure The microphone has not been adjusted to have an essentially flat frequency re...

Page 610: ...hone measures very small forces low level sound can run about one billionth of a PSI Every measurement instrument changes the thing being measured and for very small forces that effect can be signific...

Page 611: ...by pressures that do not create sound that can be measured in the far field Therefore measurements made here are not useful in predicting the sound levels far way or the sound power of the source Geo...

Page 612: ...is the percentage of time a person is exposed to noise that is potentially damaging to hearing Zero represents no exposure and 100 or more represents complete exposure It is calculated by dividing the...

Page 613: ...hanges in a medium solid liquid or gas that propagate to distant points It is characterized by changes in density pressure motion and temperature as well as other physical quantities Not all rapid cha...

Page 614: ...re k is the Exposure Factor See Exchange Rate Standard ANSI S1 25 Sound Exposure Level SEL LET The total sound energy in a specific time period The equation for it is The sound pressure is squared and...

Page 615: ...es the pressure takes the time average and then takes the square root this is called rms for root mean square There are several ways this can be done Moving Average The averaging process is continuall...

Page 616: ...reference sound pressure which is 20 MicroPascals Pa There are various descriptors attached to this level depending on how the actual sound pressure is processed in the meter Instantaneous The time va...

Page 617: ...ding will depend on the time weighting applied Unweighted Peak The peak value of a sound with a meter that has flat frequency weighting and a peak detector Weighted Peak The peak value of a sound with...

Page 618: ...hat identifies it such as sound pressure spectrum It is generally expressed as a spectrum level Threshold Sound Level Lt The A weighted sound level below which the sound produces little or no Noise Do...

Page 619: ...decay The reason for the double constant is to allow the very short signal to be captured and displayed Vibration The oscillatory movement of a mechanical system generally taken to be solid It is use...

Page 620: ...r the time delay in sound propagation It is related to wavelength through the following equation where is the wavelength c is the sound speed f is the frequency in Hz and is the radian frequency It ha...

Page 621: ...o accomplish this task Memory usage for the LOG and SSA instruments will be presented separately An example in the form of a Memory Usage Worksheet will be included for the LOG instrument LOG Memory U...

Page 622: ...ng on Interval tab of 824 Utility 384 Wind Tach Yes 5 Options add bytes shown if enabled Bytes Basic Daily Record 175 Save Daily Ln Yes 18 Daily Ln Table Enabled by Store Complete Histogram on Daily t...

Page 623: ...ng from a factory near a residential area From an initial site survey it is discovered that all trucks are over 65dBA at the boundary of the road and residential property and that there seems to be a...

Page 624: ...our 1440 1 440 24 TOTAL Hist Bytes Day Multiply lines 22 23 copy to line 28 11 520 Line Memory Use per Day Calculation Bytes 25 Exceedance History bytes day from line 5 18 720 26 Interval History byte...

Page 625: ...ion Bytes Used Bytes Needed 1 Basic Exceedance Record 32 2 Excd Time Hist n estimated number of samples 129 bytes max 21 n 3 Wind Tach Yes 3 4 TOTAL Bytes Excd Add lines 1 thru 2 5 Anticipated Excd Da...

Page 626: ...plus 2 times each 3 enabled levels Calculate 25 1 0dB Advc Wind Tach Yes 2 26 0 1dB Advc Wind Tach Yes 4 27 TOTAL bytes Hist Record Select the appropriate number of bytes from lines 19to 26above 28 H...

Page 627: ...9 29 09 E 7 824 SSA Memory Usage Interval Records Intv History Enabled Table E 8 SSA Memory Usage Interval Records...

Page 628: ...max Impl C option 2 1 Lmax Impl Flat option 2 1 Lmin Slow A option 2 1 Lmin Slow C option 2 1 Lmin Slow Flat option 2 1 Lmin Fast A option 2 1 Lmin Fast C option 2 1 Lmin Fast Flat option 2 1 Lmin Imp...

Page 629: ...r Histories and Memory Usage Other Histories and Memory Usage bytes Run Log History 20 bytes per record Calibration Log History 17 bytes per record SSA File Store with Enable Ln No 2503 each file SSA...

Page 630: ...E 10 824 Reference Manual 9 29 09...

Page 631: ...Section 9 3 These data represent the performance of the instrument when used with the Larson Davis Model 377B41 microphone Reference Sound Pressure Level 114 dB Reference Level Range Microphone Refere...

Page 632: ...0 1 0 1 0 1 0 1 0 1 0 25 1188 50 0 1 0 1 0 0 0 1 0 1 0 25 1258 93 0 1 0 1 0 0 0 1 0 1 0 25 1333 52 0 2 0 2 0 1 0 3 0 3 0 25 1412 54 0 2 0 2 0 1 0 3 0 3 0 25 1496 24 0 2 0 2 0 1 0 3 0 3 0 25 1584 89 0...

Page 633: ...0 0 45 11220 18 0 7 0 7 0 4 0 3 0 3 0 45 11885 01 0 7 0 7 0 8 0 1 0 1 0 45 12589 25 0 6 0 6 0 6 0 0 0 0 0 50 13335 21 0 1 0 1 0 6 0 5 0 5 0 50 14125 38 0 3 0 3 0 7 0 4 0 4 0 50 14962 36 0 8 0 8 0 8 0...

Page 634: ...ncy Frequency Hz 0 Free Field Cor rections from B K4226 Calibrator1 dB 0 Free Field Correc tions with Wnd Screen from B K4226 Calibrator1 dB 0 Free Field Cor rections from B K UA0033 Electrostatic Act...

Page 635: ...in ISM mode or 50 dB gain in SSA mode 31 5 Hz 1 kHz 4 kHz 8 kHz 12 5 kHz SLM ISM Normal Range 63 dB to 128 dB 19 dB to 128 dB 18 dB to 128 dB 21 dB to 128 dB 26 dB to 128 dB Low Range 59 dB to 108 dB...

Page 636: ...will display all levels over the entire linear operating range on all ranges Stabilization Time Following Changes of Environmental Conditions The typical time interval needed to stabilize after change...

Page 637: ...is not affected by electrostatic discharges Greatest Susceptibility to AC Power and Radio Frequency Fields The mode of operation of the 824 that produced the greatest susceptibility to A C power frequ...

Page 638: ...F 8 824 Reference Manual 9 29 09...

Page 639: ...from which to make your own Setups and cannot be deleted Modify each one that you need and then save that ID with your own unique name You may test drive or demo any of the non purchased permanent SET...

Page 640: ...top line Save ID and press the check key 4 A window pops up labeled ID Name 5 Press the RESET key to clear the old name 6 Push the right arrow key seven times to get to the last name charac ter 7 Pres...

Page 641: ...s also called the Residual RT 60 and is a function of the 1 3 octave filter response times Off Stopped LOG Running with backlight OFF LOG Running with backlight ON SSA Running with backlight OFF SSA R...

Page 642: ...e considered The default value for Start Level is 15 dB and provides Ln data and SPL histograms from 15 dB up to 142 9 dB Start Level is also used with the main weighted Leq in the Time History Due to...

Page 643: ...ll give a range of 35 dB up to 162 9 dB Question 5 How are Leq values calculated in the 824 and how is that different than traditional non DSP Digital Signal Processor instruments Answer First let s l...

Page 644: ...ith a fast Leq time history it can show the two impulses of the N wave and possibly even an echo or two On the other hand the older instruments will show one pulse that may take upward of 20 seconds t...

Page 645: ...n Impulse whose onset is immediately after a sample has been taken The decay for Slow is about 4dB per second and fast is 8 times faster at 32dB s In two seconds the next sample will read 8dB below th...

Page 646: ...period The peak of a continuous sine wave is 3dB higher than its RMS or SPL value Question 9 Is it possible to control the 824 Run and Stop from an external signal example 0 to 5 volt Answer Yes The L...

Page 647: ...Reset This User Reset will perform a complete memory test reset all data erase all user setup IDs Instrument Definition or setup file and recall from EEPROM one SSA one LOG and one ISM setup ID These...

Page 648: ...G 10 824 Reference Manual 9 29 09...

Page 649: ...selected measurements 10 22 export data 10 32 File Extensions 10 24 Histograms 10 32 Installation 10 1 Locking and Unlocking Setups 10 17 Modifying Setups 10 9 Opening Setup Disk Files 10 12 Printing...

Page 650: ...t 7 35 Allocated ID s 3 29 Any Data Check Menu 7 73 definition 2 3 9 5 Read Commands A 25 Any Impulse format 5 8 Any Time View 5 9 Arrow Keys 3 11 AUD 13 1 Any Level Displays 13 8 Display Sequence 13...

Page 651: ...ROM 3 19 Battery Compartment 1 20 Cover 1 20 Operating time C 6 Pack 1 18 Terminal Assembly 1 20 Baud Rate 3 34 Block Timer 3 26 Bookmarks 1 3 ByTime 11 9 C Cables Interface A 2 Microphone extension C...

Page 652: ...ark Display 7 62 Other Logging Check Menus 7 73 Other SSA Check Menus 7 65 RTA 7 66 Run Log 7 69 7 75 Settings 7 65 SLM Current Overall 7 73 SLM Options 7 62 Stats 7 75 Time History 7 68 7 76 Clock Ti...

Page 653: ...SLM Views 5 25 Threshold 7 20 Cursors Arrow Keys 3 2 Customizing printing 3 38 SSA settings 7 2 D Daily Enable 7 42 History Check Menu 7 78 History Variables A 64 Ln s 7 42 Views 5 58 Daisy Chain Addr...

Page 654: ...5 12 SSA Time History 5 16 Time History Displays 5 13 Displays Logging SLM Current Overall b SLM Displays 5 28 Current Overall c SLM Displays 5 29 Current Overall e SLM Displays 5 30 Exposure b Displ...

Page 655: ...nge Rate Factor glossary D 8 Exposure Check Menu 7 73 Views 5 31 Exposure Factor glossary D 8 External Power 1 18 External Power Source 1 20 F Fall time 13 22 Far Field D 9 acoustic D 9 geometric D 9...

Page 656: ...ector 7 9 Fractional Octave Display 5 11 Fractional Octave Fast Autostore 11 1 Fractional Octave Weighting 7 10 Fractional Octave general 6 3 Formatting Conventions 1 6 Free field D 9 Frequency band p...

Page 657: ...g Settings 7 2 Detector Settings 7 5 Gain Setting 7 6 ISM Menu Layout 7 50 LOG and SSA Intervals 7 36 LOG and SSA Ln 7 20 LOG and SSA Time History 7 30 Logging SLM Define Report 7 42 Logging SLM Excee...

Page 658: ...ct 2 2 Integrated Level Calculations B 1 Interface Cables A 2 Interval Auto Stop 7 38 Check Menu 7 76 displays 5 44 Enable 7 37 Exchange 7 39 History 6 7 Period 7 37 save Ln s 7 38 Spectral Lns 5 14 s...

Page 659: ...pdf 1 5 Ln Spectral 5 21 Ln Centiles 5 19 Check Menu 7 74 Views 5 35 Ln Settings Defining Ln s 7 22 Enable 7 21 Spectral Ln s 7 22 LOG 7 25 7 30 7 36 LOG ID 2 4 LOG Measuring Ranges 6 9 LOG Settings...

Page 660: ...nes D 12 what it measures D 13 Microphones capacitor D 13 Conforming C 1 electret D 13 uses D 13 Modem answering procedure A 76 Control Mode A 74 Dial Out Mode A 74 dialing procedure A 75 initializati...

Page 661: ...Other 7 73 Other Level Views 5 43 Overall Criterion 7 18 Criterion Level setting 7 18 Exchange 7 17 SLM Views 5 25 Threshold 7 18 overshoot 13 23 P Parameter character strings A 30 indexed A 30 numeri...

Page 662: ...n D 17 input connector 1 13 Preparing for a Measurement 4 16 Preview Display 3 11 Print Key 3 37 Printing All Long Report 8 14 All Short Report 8 14 Custom Report 8 23 Recall Format 8 7 Reports 8 2 RT...

Page 663: ...ings A 35 Commands A 8 Daily History Variables A 64 Daisy Chain addressing A 5 Data File Commands A 79 Entering Settings A 33 Error Checking I O A 48 Error Messages A 71 Exceedance History Variables A...

Page 664: ...8 Warnings A 71 Report All Long Report 8 14 All Short Report 8 14 Custom 8 23 Data 7 43 History Report 7 45 Interval Report 7 44 Peak 1 Histogram 7 44 Peak 2 Histogram 7 44 printing 8 2 Recall Format...

Page 665: ...k Menu 11 35 Detector Setting 11 6 Display Views 11 19 End Level 11 13 End Logic In 11 13 End Mode 11 12 End Samples 11 13 End Settings 11 12 End Settings Menu 11 12 End Then 11 14 End Time 11 13 Expo...

Page 666: ...age Views 11 35 Title Setting 11 6 Transducer 11 7 Trig Logic In 11 12 Trig Samples 11 12 Trigger Level 11 11 Trigger Mode 11 11 Trigger Settings Menu 11 11 Trigger Source 11 9 Trigger Time 11 11 Trig...

Page 667: ...0 intensity D 21 moving average D 19 pressure D 19 sound pressure level SPL Lp D 20 unweighted peak D 21 weighted peak D 21 Sound Exposure 6 9 Sound Level threshold Lt D 22 Sound Level Measurement 9 1...

Page 668: ...d LOG Modes C 9 Main Characteristics C 3 Max Input Voltage C 7 Measurement Range ISM LOG C 11 Measurement Range SSA C 14 Peak Detector C 10 Peak Range ISM LOG C 12 Physical Characteristics C 6 Power S...

Page 669: ...Setup 4 14 Time allowed Exposure time Ti D 1 On Off 13 23 weighting D 23 Time History 6 7 Check Menu 7 76 Displays 5 13 Exceedance 5 55 Max vs Peak level G 7 SSA Display 5 16 Views 5 42 Timer 3 23 Tim...

Page 670: ...61 Daily windy percent 5 62 Exceedance History 5 52 Exceedance Time History 5 55 Exceedance wind conditions 5 54 Exposure 5 31 general 5 4 Hourly Leq 5 63 Intervals 5 44 Intervals wind conditions 5 5...

Page 671: ...7 30 pulse source 7 30 pulse trigger voltage 7 30 settings 7 25 setup 7 26 views 5 69 Wind Direction Units 7 28 wind display 5 61 wind exceedance level 7 29 wind hysteresis 7 29 wind pause enable 7 3...

Page 672: ...iv xxiv Index Model 831 Technical Reference Manual...

Page 673: ...Total Customer Satisfaction Guaranteed 3425 Walden Avenue Depew NY USA 14043 Phone 716 926 8243 Toll Free 888 258 3222 LarsonDavis com FAX 716 926 8215...

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