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11/2/00

FFT (Optional)

11-1

C H A P T E R

FFT (Optional)

The FFT option gives the 824 the ability to do fast fourier
analysis. This chapter describes the features and functions of
this option.

Features

The FFT option has the following features:

•

400 line FFT

•

Hanning or Rectangular window

•

Bandwidths of 200Hz, 500Hz, 1kHz, 2kHz, 5kHz,
10kHz, and 20kHz

•

Count averaging (1 to 16384)

•

Snapshot data storage

•

Display zoom with a factor of 2, 4, or 8

•

Total Harmonic Distortion

•

User defined Linear Units

Settings Menu

The Settings menu for the FFT instrument is accessed from
the SETUP

key.

Содержание System 824

Страница 1: ...System 824 Reference Manual Larson Davis Inc 1681 West 820 North Provo UT 84601 1341 Phone 801 375 0177 FAX 801 375 0182 www larsondavis com I824 01 Rev g...

Страница 2: ...f the original purchase During the two year warranty period Larson Davis will repair or at its option replace any defective component s without charge for parts or labor if the unit is returned freigh...

Страница 3: ...give this information in any future communications you have with Larson Davis Inc Record of Serial Number and Purchase Date PRM902 Pre amp Serial ______________ Microphone Serial ____________________...

Страница 4: ...824 Reference Manual iv...

Страница 5: ...Setups or Instrument Definitions 2 1 Instrument Definition ID Types 2 2 SLM RTA SSA 2 2 SLM ISM 2 4 Logging LOG 2 4 Selecting a Measurement Setup 2 5 Performing a Measurement SLM RTA SSA example 2 6...

Страница 6: ...ause Key 3 10 Pause 3 10 Pause Back Erase 3 10 Preview 3 11 Arrow Keys 3 11 Check Key 3 12 View Key 3 12 Data Key 3 13 Setup Key 3 14 Save ID 3 16 Title 3 16 ID Name 3 16 Write Protect Delete Write En...

Страница 7: ...fferent ID 4 14 Accessing the Settings Menu 4 14 Accessing the Settings Menu to Initiate Editing or Modification 4 16 Setting Control in the SLM View 4 19 Chapter 5 System 824 Virtual Instruments 5 1...

Страница 8: ...28 Current Overall SLM Display c Min Max 6 29 Current Overall SLM Display d Peaks 6 29 Current Overall SLM Display e TWA 6 30 Exposure Views 6 31 Exposure Display a 6 31 Exposure b Display 6 33 Exposu...

Страница 9: ...M 7 5 Detector Setting SSA LOG ISM 7 5 Weighting Setting SSA LOG ISM 7 6 Gain Setting SSA 7 6 Range Setting LOG ISM 7 6 Transducer Setting SSA LOG ISM 7 7 Random Incidence Microphone Correction 7 8 Pk...

Страница 10: ...SSA 7 22 Hysteresis LOG SSA 7 22 LOG and SSA Time History Settings 7 23 Hist Enable LOG SSA 7 25 Hist Period LOG SSA 7 25 Period Units LOG SSA 7 25 Other Level LOG only 7 26 Resolution LOG SSA 7 27 A...

Страница 11: ...SSA Settings 7 37 Menu Layout of Integrating SLM ISM Settings 7 43 Menu Layout of Logging SLM Settings 7 46 Check Menus 7 52 Check Menu Example 7 53 SLM Check Menu Options SSA and LOG 7 55 Mark Displa...

Страница 12: ...y Software 9 2 Connecting the 824 to Your Computer 9 2 824 Utility Tool Bar 9 4 824 Utility Setup Window 9 6 Retrieving setups from the 824 9 7 Modifying and Storing Setups to the 824 9 9 Manipulating...

Страница 13: ...ed 10 13 RTA Settings 10 15 RT60 A and RT60 B Instrument Definition 10 16 Rooms RTA Instrument Definition 10 17 Display Views 10 18 RTA Views 10 18 Trigger Views 10 22 Autostore Views 10 25 Autostore...

Страница 14: ...Pulse FM Check Menu 12 15 Appendix A Integrated Level Calculations A 1 Basic Integrated Level Calculations A 1 Appendix B Serial Port Interface Remote Control B 1 Interface Cables B 2 Connection to a...

Страница 15: ...ly History Variables D1 D102 B 54 Run Log Variables SSA ISM LOG TAL B 56 Calibration History Variables LOG B 56 Time History Variables SSA LOG TAL B 57 Time History Variables SSA LOG TAL B 58 Histogra...

Страница 16: ...Eight Hour Time Weighted Average Sound Level L TWA 8 D 5 Energy Equivalent Sound Level Leq D 5 Exchange Rate Q Exchange Rate Factor q Exposure Factor k D 6 Far Field D 6 Free Field D 6 Frequency Hz ra...

Страница 17: ...16 Sound Power W D 18 Sound Power Level PWL Lw D 18 Sound Speed c D 18 Spectrum Frequency Spectrum D 18 Threshold Sound Level Lt D 18 Time Weighted Average Sound Level TWA LTWA TC D 19 Time Weighting...

Страница 18: ...824 Reference Manual xiv...

Страница 19: ...to the con tents 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 over...

Страница 20: ...speed data gathering option enables you to perform architectural acoustics impulse event analysis and passby event analysis Chapter 11 FFT Optional Describes the features and functions of the fast fo...

Страница 21: ...ing conventions used in this manual Features Gives an overview of the System 824 keypad functions and measurement capabilities Getting Started Provides instructions for unpacking inspecting and initia...

Страница 22: ...features Large backlit bitmapped graphic display Soft rubber backlit keys Pop up menus with scroll bars Pick and choose setup just click and run File management system stores multiple measurements Mul...

Страница 23: ...satisfying IEC 1260 1995 Class 1 and ANSI S1 11 1986 Type 1 D meeting linearity specifications over a range of 85dB 1 1 octave 16 Hz to 16 kHz 11 filters 1 3 octave 12 5 Hz to 20 kHz 33 filters Automa...

Страница 24: ...time history 70 000 RTA 1 1 octave spectra 28 000 RTA 1 3 octave spectra 2400 FFT 400 line snapshots AC DC output unweighted with gain to 50 dB and attenuation to 20 dB Flash memory for in field firm...

Страница 25: ...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 powe...

Страница 26: ...igure 1 3 The control connector is a 9 pin mini DIN connector 1 Ground 2 Logic output 0 to 5 volts active high 3 Logic input 0 to 5 volts active high 4 Wind speed input 05 to 10 Vdc peak to peak 5 Win...

Страница 27: ...ve input RS 422 6 Transmit data positive output RS 422 7 Control input RS 232C levels 8 Receive data positive input RS 422 Both outputs have a 600 ohm series resistance The AC DC output connector is u...

Страница 28: ...an electrical signal by the microphone This electri cal signal is filtered and sampled by an analog to digital converter ADC The processor then calculates all of the desired data based on the sampled...

Страница 29: ...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 Crystal Display LC...

Страница 30: ...ed on the label on the instrument s back panel The microphone s Model Serial numbers are located on the inside ring of the microphone The pre amplifier s Model Serial numbers are engraved the outside...

Страница 31: ...8 Class 1 CAL250 Sound Level Calibrator 250 Hz 114 dB IEC 942 1988 Class 1L Microphone extension cables are available in 1 5 6 10 20 25 35 50 66 100 and 200 foot lengths or custom lengths up to 328 fe...

Страница 32: ...tteries remove the battery cover and if installed remove depleted alkaline batteries or NiMH bat tery pack If not already installed insert a battery Terminal Assembly AM814 06 so that it is positioned...

Страница 33: ...ging See page 3 6 You may use an external power source via the external power connector using the provided power adapter The Sys tem 824 accepts 6 to 15 VDC and is internally fused at 0 5 A Terminal A...

Страница 34: ...1 16 824 Reference Manual 11 8 00...

Страница 35: ...the existing list of instrument definitions The System 824 was designed to be upgraded with new instrument capa bilities as they are made available Please contact Larson Davis for information on the l...

Страница 36: ...vel Lmax spectrum which is the spectrum time coincident with the maximum value of the sound pressure level during the measurement period A back erase function allows the removal of up to the last 30 s...

Страница 37: ...the following sound level parameters a feature we call Any Data Peak Sound Pressure Level Lpeak with A C and Flat weighting Equivalent Continuous Sound Pressure Level Leq with A C and Flat weighting A...

Страница 38: ...ing is required the measurement linearity range is 105 dBA permitting the use of a single range for all mea surements Logging LOG This ID is designed particularly for noise monitoring appli cations an...

Страница 39: ...tic measurement and log ging of data associated with noise exceedance events that are triggered by the sound level exceeding a user defined threshold Leq SEL and LPeakfor each event are logged along w...

Страница 40: ...op of the list below the Edit Setting message Pressing the ckey while the Edit Settings menu item is highlighted initiates the modification procedure After selecting a measurement setup press the skey...

Страница 41: ...btain a display resembling the follow ing The large numerals represent the SPL measurement taken with the Slow detector and the A weighting In the lower left is an indication of the Leq value and the...

Страница 42: ...erasing the data to the right of the cursor This is the Back Erase feature as indicated on the display when the pkey had been initially pressed Changing the detector of the displayed SPL value You ca...

Страница 43: ...e therorlarrow keys to display the C weighted or Flat weighted SPL corresponding to the Slow detector Changing the displayed secondary parameter Step 1 To select the secondary parameter to be displaye...

Страница 44: ...s example the measure ment range is 80 dB unlike the ISM and LOG IDs for which it is 105 dB In order to optimize a particular measurement provisions have been made to select a value of input gain dire...

Страница 45: ...et of data displays or VIEWS are available Selecting a VIEW There are eight different VIEW choices available in the SSA instrument Step 1 To display the set of available data presentations or VIEWS pr...

Страница 46: ...ound 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 Instant...

Страница 47: ...ata can be stored to non vola tile 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...

Страница 48: ...eys until the desired file is indicated Press the check c key select Recall from the menu and press the check ckey again Calibration Calibration is one of the functions available from the Tools Menu S...

Страница 49: ...press the dand ukeys to highlight Cal Level Step 5 To set the value of the sound level provided by the calibrator press therkey This displays the Cal Level window Step 6 Then use thelandrkeys to move...

Страница 50: ...and press cto 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 cali...

Страница 51: ...apter contains an overview of the functions which are accessed through the System 824 keypad see Figure 3 1 below Figure 3 1System 824 Keypad The 14 keys on the System 824 keypad are organized into th...

Страница 52: ...e function R RESET Displays Reset options menu Current Overall Options u u u u l d ARROW Used to move through System 824 menus change settings and scroll through data displays The key exits menu s c S...

Страница 53: ...he 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 vkey until prom...

Страница 54: ...the PWR display To do this Step 1 Press the vkey so that the following PWR dis play appears Pressing thelor v key again will return you to the previous dis play From this display you can adjust the c...

Страница 55: ...utomatically 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 m...

Страница 56: ...Battery Please Wait Simply press the power key again and the 824 will shut off The charge mode will be activated automatically when external power is applied and the battery is at 75 capacity or less...

Страница 57: ...key presses for the period of time set by the Auto Off Time set ting the instrument will turn off Manual Off No automatic power reduction features are enabled Auto Off Time 0 99 minutes When Auto Off...

Страница 58: ...ing is 66 Adjusts the contrast or viewing angle of the LCD display This is done by pressing either the up or down arrow key The u u u ukey increases the contrast percentage darkens the display and mak...

Страница 59: ...the accumulated measurement values such as Leq The SSA ISM and LOG instruments within the System 824 contain two independent data buffers that can separately accumulate data In essence the instrument...

Страница 60: ...e 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 pagain to resume the measurement The fol l...

Страница 61: ...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...

Страница 62: ...ailable data displays which are selected using this key When you press the Vkey a menu containing the available data displays will appear The fol lowing example is a View menu for the SSA instrument T...

Страница 63: ...lar to the following appears A new System 824 will not contain data files for recall From this menu you can store data or view and recall stored data If the instrument is running when you try to store...

Страница 64: ...at were stored with that data file The data file also contains calibration information that is dif ferent than the current calibration When Run is pressed the recalled calibration is replaced by the l...

Страница 65: ...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 of a particular measurement application is an entire t...

Страница 66: ...characters form the name and the last three are the extension that indicate the instrument type e g SSA The name does not have to be a full 8 characters long Leading spaces and symbols will be removed...

Страница 67: ...the c key The ID is removed from memory and the ID name is removed from the Setup menu To write enable or unlock an ID use the uor dkeys from the Setup menu to highlight the desired write protected I...

Страница 68: ...at Normal or ISO 8601 Takt enables German func tionality Yes or No a System revision information b User information c Installed instrument options Calibration Check Change Cal Level Calibrator S N Noi...

Страница 69: ...y Time Backlight Time Backlight LCD Contrast External Power Min Battery Activate Battery Charger Battery and external power status battery type and internal temperature Communication Baud Rate 300 115...

Страница 70: ...the owner s name and address The name is displayed at power on and printed on reports to customize them to your business About Settings edit mode can also be edited by pressing the c key from the Abo...

Страница 71: ...Pressing therkey again moves to the About c screen The following screen appears The About c display shows the system s currently available instruments Additional instruments can be added to the Sys t...

Страница 72: ...dkey to select Calibration from the Tools menu then press therkey The Calibration menu provides the following settings Check Activates the calibration check level verification process Change Activate...

Страница 73: ...e Time b screen The following appears The Time b or timer display shows the current timer pro gramming including the mode and the appropriate run and stop times and dates Clock Timer Settings can be c...

Страница 74: ...Run Stop Time 2 allow you to control the timer function IF the date has not been set month shows as then the message Time not set will be shown when the Run key is pressed Current Time Date To set th...

Страница 75: ...rtain time on one day and ending at a certain time on the same or another day NOTE If the run time is later than the stop time then a measurement will start on the stop date and end at the stop time o...

Страница 76: ...Time 1 Stop Time 1 These settings allow you to specify the beginning and ending times of a measurement NOTE If you have selected the Block 1 Day or 2 Day mode the timer will automatically turn the ins...

Страница 77: ...re displayed In addition the Memory a display shows the number of pre viously stored records of various types for the active ID Pressing therkey again moves to the Memory b screen The following appear...

Страница 78: ...memory This clears the memory The default value of this setting is 10 allocated setup registers which uses 5120 bytes of memory The System 824 has ten permanent ID registers These pre defined ID regis...

Страница 79: ...kes the memory very efficient compared to fixed sector file allocation table based mem ory structures and sequencial forward and reverse data retrieval is very fast It does not allow us to delete data...

Страница 80: ...tents Choosing Open also allows you to delete individual records from the file after it has been opened See below for instructions on deleting individual records Open Choosing Open recalls the file in...

Страница 81: ...l record and decide whether to delete or store it with new data appended to it Follow these steps to delete individual records Step 1 The last display that was viewed will appear after selecting Open...

Страница 82: ...delete the record The next record will appear Continue this process until you have deleted all of records that you don t want Power Monitor This menu option allows adjustment of the auto power off the...

Страница 83: ...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 the System 824 communicates with controlling devices computer...

Страница 84: ...ess Address of instrument This setting identi fies the instrument within a network of instruments by assigning it a network or serial address Flow Control Flow control of the serial connection Flow co...

Страница 85: ...ed information about the Modem Mode Modem Mode Turns the modem mode on or off to allow communication to a telephone modem Dial Out Mode The 824 will dial out on an Exceedance or an Alarm or both Phone...

Страница 86: ...t The modem initialization string is entered here Initialize The modem initialization string is sent out the RS232 port Print Key Refer to Chapter 8 Printing a Report for more information on printing...

Страница 87: ...g upon the specific instrument being used With an appropriate printer connection you can print a num ber of reports The Recall Format sub menu option is used to enable various reports Do this by highl...

Страница 88: ...3 38 824 Reference Manual 11 8 00...

Страница 89: ...ed settings properly config ured you can easily take a measurement and examine the readings from the data collected Taking an actual measure ment with the System 824 is as easy as pressing the s RUN S...

Страница 90: ...press the v key located on the left side of the key pad By pressing this key the Larson Davis logo appears while a number of tests are performed The fol lowing screen then appears for a few seconds St...

Страница 91: ...e calibrator and follow the on screen instructions Taking Measurements and Storing Data This section provides examples of how to select an instru ment ID take a measurement and store the resulting dat...

Страница 92: ...the SLM RTA SSA item and press the 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 VVIEW key Use the uor d...

Страница 93: ...rent measurement readings press the DData key Select Store File and press the key This will store the measurement s data Step 7 To turn off the instrument press and hold the v key until you are prompt...

Страница 94: ...A 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 th...

Страница 95: ...ll move along the graph to the posi tion that 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 fo...

Страница 96: ...ent RTA screens Step 11 Press the RUN STOP s key to stop the current reading If you attempt to store data while a measurement is still running a warning will be displayed indicat ing that the measurem...

Страница 97: ...eck key The following appears The Data Files screen shows the currently selected record number the ID used to take the measurement the start stop dates and times and the total bytes used by the record...

Страница 98: ...tored using the Setup Menu of the System 824 More detailed descrip tions for specific Instrument Types e g ISM LOG or SSA will be provided in later chapters When a PC is available the 824 Utility soft...

Страница 99: ...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...

Страница 100: ...will be vertical bar If this vertical bar extends from the top to the bottom of the vertical window then all items in the list are shown in the display If the vertical bar does not cover the length of...

Страница 101: ...changed when the modified ID is stored so that it does not conflict with the names of any permanent IDs Write protected IDs Those with a symbol of a padlock to the left are user defined IDs which have...

Страница 102: ...the Active ID 3 Select a different ID make it the Active ID and mod ify it as required Selecting a Different ID Use the dand ukeys to highlight the desired ID and make it the Active ID by pressing the...

Страница 103: ...sions of the System 824 include the SSA Instrument Type we want to select the permanent ID SLM RTA SSA as the Active ID Press Sto open the Setup menu Step 1 If the Active ID in your instrument is an u...

Страница 104: ...order to view or edit the Active ID In many cases the cCheck key will accomplish the same result This will produce the Settings menu list as shown below Note that all of the items in this list with th...

Страница 105: ...though we will not do this in the present example we could highlight Detector noting that it is presently SLOW pressrto open a window listing the SLM Detector selec tions highlight FAST and press cto...

Страница 106: ...the Setting menu structure using repeated presses ofl con sider the following diagram illustrating the actions which have been taken so far in the example above In this particular instance when therke...

Страница 107: ...thout the need to usedto move the highlight down from the first item If one chooses to use thelandrkeys to move between Menus and prefers to enter each Menu with the first item highlighted simply use...

Страница 108: ...ess thelorrkey to change the selection The table below shows how to use the arrow keys to navi gate through the settings on the SLM display Key Action d Moves to the next setting u Moves to the previo...

Страница 109: ...particular application You can of course create new setups for particular applications and add your own IDs to the Sys tem 824 The SLM RTA SSA Logging LOG and Integrating SLM ISM instruments are avai...

Страница 110: ...LEQ SEL Min Max Peak with all weights A C Flat and with all detectors slow fast impulse peak and Leq simulta neously plus 1 1 and 1 3 octave data stored in time and interval histories at storage rates...

Страница 111: ...1 Press the SSETUP 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 mai...

Страница 112: ...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 with a typical...

Страница 113: ...utput of channel 1 AC 1 AC output of channel 2 AC 2 DC output DC The two possible output signals are on the tip and the ring of the 3 5mm jack The sleeve is ground The selection in the 824 controls se...

Страница 114: ...ng SLM The Logging SLM LOG instrument is ideal for applica tions requiring the automatic measurement and storage of multiple parameters over an extended period as required for environmental noise moni...

Страница 115: ...nterval History parameters can be logged at user selectable time intervals between 1 second and 99 hours hh mm ss Lmax Lmin SEL and Leq q 3 or Time Weighted Aver age q 4 5 or 6 levels for a selected d...

Страница 116: ...rcentile values For example setting one of the six settings to 10 5 would show the SPL that has been exceeded 10 5 of the time during the time of overall measurement These settings can each take on an...

Страница 117: ...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 100 The following are examples...

Страница 118: ...5 10 824 Reference Manual 9 12 00...

Страница 119: ...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...

Страница 120: ...ollowing table describes the icons that may appear Icon Description Animated Running Figure The instru ment is running and acquiring data Solid Box The instrument is stopped data available Open Box Th...

Страница 121: ...Block with Dark background and Light numer als Shows linerarity range Bar and Play Symbol The instrument is in pre view Current SPL and peak levels are dis played but no data is being acquired Animat...

Страница 122: ...a screen similar to the fol lowing will appear Step 2 Use the uand darrow keys to highlight the desired view Step 3 Press the Check ckey and the desired view will appear SLM Views The SLM view is ava...

Страница 123: ...s Display label The Display label identifies the display The example above shows the SLM view for the SLM RTA Instrument ID Selected detector The selection determines which detec tor s data e g Fast S...

Страница 124: ...isplays the current run time for the mea surement It resets to zero when the R RESET key is pressed pauses when the pPAUSE key is pressed and continues when the pPAUSE key is pressed again The timer i...

Страница 125: ...allow you to change the Any Data format you are viewing Thelandrarrow keys move you through each of the Any Data formats available displays Any Level Format In this view five different tables present...

Страница 126: ...e different tables present Impulse weighted parameters alongside similar Fast weighted parameters mea sured with A C and Flat weighting as follows Any Time Format In this view seven different displays...

Страница 127: ...n the SSA instrument the RTA Live instantaneous spec trum the RTA Leq or time weighted averaged since last reset spectrum RTA Max spectrum which is the spectrum time coincident with the maximum value...

Страница 128: ...ncy during the measurement Intervals Shows an Leq spectrum Max or Min spec tral data a broadband Leq Lmax Lmin SEL Lpeak and Spectral Lns for each interval period SLM Time His tory Shows the Leq for e...

Страница 129: ...el and frequency values shown the left side of the display The cursor or frequency bar position can be changed by pressing therorlarrow keys As the arrow keys are pressed the vertical bar moves to the...

Страница 130: ...Tabular using the uor darrow keys then press the ccheck key A tabular dis play like the following screen appears Step 3 To return to the graphical view press the c check key and the following menu ap...

Страница 131: ...yed The SSA instrument has 4 unique interval displays which show the Max spectra at the time the broadband level was at maximum Min spectra which is a bin by bin minimum the Leq or average of each fre...

Страница 132: ...frequency Also there are six graphical displays showing spectra for each of the six Ln values In order to turn on the Spectral Lns for the interval period go to the SSA settings menu and select Inter...

Страница 133: ...key to view the INTV Ln f display Use the right rand leftlarrow keys to move to each one third octave frequency To view the Spectral 1 through Spectral 6 displays the 6 Ln values use the up uand down...

Страница 134: ...6 16 824 Reference Manual 11 8 00 SSA Time History The SSA Time History display consists of six major compo nents Display label Record number SPL reading at cursor Other level Status SPL history graph...

Страница 135: ...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...

Страница 136: ...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 lev els selected in the TH setup Use the u...

Страница 137: ...h light 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 whe...

Страница 138: ...no longer available See page 3 10 for information on the Back Erase fea ture Use the right rarrow key to view the SSA Ln b display The following is a brief description of each of the compo nents of t...

Страница 139: ...these displays will indicate No Data Available for1 1 octave This is a tabular display for each 1 3 octave frequency show ing six Ln values for the selected frequency Below is an example of one of the...

Страница 140: ...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...

Страница 141: ...using the Logging SLM LOG instrument Addi tionally the uor 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 Lev...

Страница 142: ...ause and date time of occurrence Time History Show the time history of Leq and option ally many other levels such as Lmax Lpk or Advanced TH setup items over short duration periods Intervals Shows a f...

Страница 143: ...the Current SLM Overall SLM Exposure Ln Centiles and Stats views The Current SLM and Overall SLM Views have five com mon displays which can be cycled through using therandlar row keys Since these disp...

Страница 144: ...he 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 desired view The land rarr...

Страница 145: ...urrent 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 when the RRe...

Страница 146: ...represents both Current b and Overall b display Start date time Date and time the current overall measure ment began Elapsed time The Elapsed Time displays the length of time the current or overall m...

Страница 147: ...r example SLM Current c The display represents both Current and Overall c display Current Overall Lmax reading Displays Lmax or maxi mum level that occurred and the date and time when it occurred Curr...

Страница 148: ...tector 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 824 s peak detector along with the date and time tha...

Страница 149: ...he TWA normalized to one second Elapsed time This shows the elapsed run time accumu lated since the last current overall reset This is the time over which the current TWA is averaged Exposure Views Th...

Страница 150: ...equal to the criterion time usually eight hours This corresponds to the maximum safe noise expo sure Exposures at higher levels will result in a 100 dose in less time or if exposure continues the exp...

Страница 151: ...each of the display s components Display label Shows the current display for example SLM Exposure b Takt3 and Takt5 are available options if German functionality has been enabled See the TOOLS menu on...

Страница 152: ...If German functionality has been enabled the Exposure b display will look as shown below Exposure c Display The Exposure c display consists of four major components Display label C Weighted TWA A Wei...

Страница 153: ...ted TWA Leq 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 S...

Страница 154: ...an 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 one of the six percentiles that is displayed The value of L10 5 i...

Страница 155: ...ar in the graph The higher of the two is graphed Stats Views The Stats View has three displays which can be accessed by simply selecting Stats with the cCheck key from within the main View menu then c...

Страница 156: ...d this threshold 0 times These may be considered as individual events Trigger level 2 and event counter Summary of the num ber of times during the overall measurement that the SPL exceeded the pre pro...

Страница 157: ...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 times during the overall measurement that the Peak II lev...

Страница 158: ...loads 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 active measurement in the...

Страница 159: ...e shows the time and date that this Log entry either started to run or was stopped Run Stop Indicator Each measurement reading log has two entries one corresponding to when the measurement started to...

Страница 160: ...SLM Time History Status Indicator The Status Indicator will show one of the three possible events that occurred in the point of time refer enced by the Time Cursor Run Indicates a measurement started...

Страница 161: ...uand down dar row keys to scroll through other data stored Intervals The uand darrow keys show different intervals in history The land rarrow keys cycle you through the different Interval screens The...

Страница 162: ...a tion to the other interval records Interval Date Time The Event Date Time shows the time and date that this interval began Leq Reading The Leq Reading shows the Leq for the cur rently displayed inte...

Страница 163: ...rred The Interval Number indicates the order of the displayed interval in rela tion to the other interval records Interval Date Time The Event Date Time shows the time and date that this interval bega...

Страница 164: ...s shows the current display for example Interval c Interval Number The Interval Number display shows each measurement interval in the order that it occurred The Inter val Number indicates the order of...

Страница 165: ...Peak I Exceedances Peak II Exceedances Overloads The Interval d display is shown below for the LOG and SSA instruments The following explains each of the display s components Display label This shows...

Страница 166: ...l was surpassed Overloads This shows how many overloads occurred dur ing this interval Intervals e Display The Interval e display consists of three major components Display label Interval Number Ln Ce...

Страница 167: ...orded when the sound pressure level went over a prede termined threshold You can access the Excd History view display by selecting Excd History with the cCheck key from within the main View menu Excd...

Страница 168: ...ce records Exceedance Date Time The Event Date Time shows the time and date that this exceedance occurred Leq Reading The Leq Reading shows the Leq for the cur rently displayed exceedance SEL Reading...

Страница 169: ...The Peak I Reading shows the Peak I level recorded during this exceedance Peak II Reading The Peak II Reading shows the Peak II level recorded during this exceedance Maximum Reading The Max Reading s...

Страница 170: ...Time History display is shown below The following explains each of the display s components Display Label This shows the current display for exam ple Excd TH Current Record The Excd TH display shows e...

Страница 171: ...time history Daily Views The Daily history logs daily sound statistics including Leq 24 LDN CNEL Ln s Max Min and Peak data The mea surement period is from 12 00 midnight to 12 00 midnight each day F...

Страница 172: ...daily record is created each new day A day is defined as 12 00 midnight to 12 00 midnight Elasped Time This shows the elapsed time of this day s measurement Date This shows the day date month and yea...

Страница 173: ...applied Daily b Display The Daily b display consists of 4 major components Display label Record Number Date Ln Percentiles The Daily b display is shown below The following explains each of the display...

Страница 174: ...Leq Display The Hourly Leq display consists of 7 major components Display label Date Record Number Hourly Leq reading Exceedance Leq Background Leq Partial hour indicator Hourly Leq graph The Hourly L...

Страница 175: ...rement was not for a full hour Hourly Leq graph This graph shows the Leq value for each hour Use the randlarrow keys to move the cur sor to view the Leq background Leq and exceedance Leq for each hour...

Страница 176: ...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...

Страница 177: ...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...

Страница 178: ...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...

Страница 179: ...ed Time This shows the elapsed time between the 10dB down points prior to and following the maximum level measured NOTE The Passby triggering system can be used to create an exceedance record of each...

Страница 180: ...6 62 824 Reference Manual 11 8 00...

Страница 181: ...SM 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 ISM...

Страница 182: ...set tings 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 ca...

Страница 183: ...e menu by using the or keys and then pressing the Check key The SLM RTA screen appears The System 824 is now set to the SLM RTA SSA instru ment Step 3 To access the Settings menu press the Setup key T...

Страница 184: ...SSA instrument s Detector setting is now set to Fast Press the SSetup key to close the menu and return to the SLM RTA view Settings Descriptions Within the Edit Settings menu use the and keys to move...

Страница 185: ...these instruments Title Setting SSA LOG ISM To change the Title use the and keys to select each charac ter Use the and keys to replace the selected letter Pressing the Reset key clears all charac ters...

Страница 186: ...the amplification of the microphone s signal The lowest and highest levels that can be measured accurately are indicated by each live dis play s graph scale this setting provides the following options...

Страница 187: ...n when you need to measure extremely high or low sound levels Transducer Setting SSA LOG ISM Transducer sets the desired transducer This setting provides the following three settings NOTE Using an ele...

Страница 188: ...ulating Stop to View will be displayed Pk Weighting SSA LOG ISM The 824 has peak detectors for A C and Flat frequency weighting that measure simultaneously the greatest instanta neous level Lpk that h...

Страница 189: ...andwidth filters for real time fre quency analysis This setting has the following two options NOTE The SSA instrument only mea sures data using 1 3 octave filters It sums the 1 3 octave bands to give...

Страница 190: ...xcd Logic Out Time 0 255 sec Logic Out 2 Same settings as Logic Out Logic Out 2 Timer 0 255 sec Heater On Yes No E A Cal Tone Yes No NOTE The Logic out 2 uses the Heater output line if set to somethin...

Страница 191: ...dingly the setting provides the follow ing five options None The state of the logic input pin has no effect Pause Whenever the logic input is connected to 5V e g when a push button switch makes con ta...

Страница 192: ...hreshold set by the SPL Trig ger Level setting The Any Data SPL used is the one specified by the Weight and Detector settings Peak The Logic Output turns on when the instantaneous peak level Peak I sp...

Страница 193: ...urs on one of the A D channels P I A The Logic Output turns 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...

Страница 194: ...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...

Страница 195: ...er 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 do...

Страница 196: ...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 System 824 s...

Страница 197: ...ge 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 a...

Страница 198: ...eshold 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 criterion...

Страница 199: ...he SSA instrument then the Back Erase feature is no longer available See page 3 10 for information on the Back Erase fea ture Yes The six Ln levels are stored for the overall measurement Start Level T...

Страница 200: ...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 func tion of each Interval History record None Spectral Ln s a...

Страница 201: ...gs Each setting is then described in greater detail SPL Excd Lvl 1 LOG SSA The SPL Excd Lvl 1 sets the SPL trigger level that exceed ance records are triggered from LOG only You can also view a count...

Страница 202: ...the Weight setting This setting can include any integer value within the follow ing 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 Pk...

Страница 203: ...samples per second with the SSA instrument Since this function continues stor ing data as long as the measurement is in progress the com bination of a fast storage rate and a long measurement time ca...

Страница 204: ...1 0 dB Adv TH Activates a set of 3 displays used to configure what time history data will be stored See page 7 26 Marker Text Marker 1 Aircraft Marker 2 Automble Marker 3 Truck Marker 4 Train Marker 5...

Страница 205: ...setting can include any integer value in the following range 0 to 255 Period Units LOG SSA Period Units selects the type of units the instrument uses to calculate the time which transpires between su...

Страница 206: ...he history period will be forced to multiples of 4 to support the maximum data rate of 8 samples per second and the warning Setting Conflict is displayed 1 0s This sets the history period unit to one...

Страница 207: ...l stored Levels are rounded to the nearest integer 85 5 would be stored as 86dB and 85 4 would be stored as 85dB Advanced Time History LOG SSA Up to 38 different parameters can be stored LOG and SSA w...

Страница 208: ...cription See page 7 55 for a description of the Marker display LOG and SSA Interval Settings Interval Settings are available on the LOG and SSA instruments The Intervals menu sets the System 824 to au...

Страница 209: ...then Ln s are turned on and the warning Set ting Conflict is displayed Intv Period LOG SSA Intv Period sets the time interval between successive inter val storage operations These storage operations c...

Страница 210: ...tart of the next time segment at which time a new synchronized storage interval will begin This setting provides the following two options No Disables interval synchronization Yes Enables interval syn...

Страница 211: ...A The Intv Exchange sets the exchange rate sometimes called the doubling rate that is used to calculate the interval TWA The exchange rate reflects the relationship between the permitted exposure leve...

Страница 212: ...are only available to the Logging SLM LOG instrument Exceedance History settings allow you to select what data will be saved in memory during an exceedance An exceed ance is defined as an acoustic ev...

Страница 213: ...OG The Excd Trigger setting enables you to select whether the Exceedance Trigger utilizes the fixed trigger levels or uses a special 10 dB rise then fall Passby trigger This setting pro vides the foll...

Страница 214: ...ata such as listed above This setting provides the 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...

Страница 215: ...t 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 Set...

Страница 216: ...he 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 con tains a histogram of the Pea...

Страница 217: ...k 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 Yes The history report will print Menu Layout...

Страница 218: ...FLT RTA RTA Detector Slow Fast RTA Weighting A C FLT Bandwidth 1 1 1 3 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 Thresho...

Страница 219: ...0 255 default 60 Period Units 1 32s 1 0s 10 0s 60 0s Resolution 0 1db 1 0db TH Setup Activates a set of 3 dis plays used to configure what time history data will be stored See page 7 27 Marker Text M...

Страница 220: ...default 66 67 Ln 6 Percent Selectable default 90 Spectral LN None Overall Interval Trigger ing SPL Excd Lvl 1 0 255 dB default 115dB SPL Excd Lvl 2 0 255 dB default 120dB Pk 1 Excd Lvl 0 255 dB defau...

Страница 221: ...port No Yes Intv Report Short Long Hist Report No Yes Controls AC DC Output AC 1 AC 2 AC 1 DC AC 2 DC AC 2 AC 1 Logic In Mode None Pause Toggle Level Alarm Logic Out Off RMS Peak R P Intv R I P I R P...

Страница 222: ...Reference Manual 11 8 00 Controls contin ued 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 Excd Logic Out 2 Time 0 255 sec Heater On No Yes E A Cal Ton...

Страница 223: ...tion is a table depicting the menu layout of the ISM instrument s Standard Settings ISM Setting Menu Items Submenu Available Settings Options Title User customized text entry SLM Detector Slow Fast Im...

Страница 224: ...7 44 824 Reference Manual 11 8 00 Controls AC DC Output AC 1 AC 2 AC 1 DC AC 2 DC AC 2 AC 1 Logic In Mode None Pause Toggle Level Alarm...

Страница 225: ...Logic Out 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 Excd Logic Out Time 0 255 sec Logic Output 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...

Страница 226: ...table depicting the menu layout of the LOG instrument s Standard Settings LOG Settings Controls contin ued Heater On No Yes E A Cal Tone No Yes Menu Items Submenu Available Settings Options Title Use...

Страница 227: ...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...

Страница 228: ...ts 1 32s 1s default 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 s...

Страница 229: ...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...

Страница 230: ...Data Report Yes default No Setup Report Yes default No SPL Histogram Yes No default Pk 1 Histogram Yes No default Pk 2 Histogram Yes No default Intv Report No Short default Long Hist Report Yes defau...

Страница 231: ...ing ID Setting Files 7 51 Controls continued Logic In Mode None Pause Toggle Level Alarm Logic Out 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 Excd Logic Out Time...

Страница 232: ...accessed simply by press ing the cCheck key from within the System 824 s different views The available Check menu options vary between an instru ment ID s different views The options available from e...

Страница 233: ...menu is accessed by simply pressing the Check key from within an Instrument ID s view The follow ing is an example of using the Check menu from a SLM view to change the Detector setting from the sele...

Страница 234: ...following appears Step 3 Use the uand darrow keys to highlight SLM then press the cCheck key or the r arrow key A menu similar to the following appears Step 4 Use the uand darrow keys to highlight Wei...

Страница 235: ...ted puts you in the Mark display The following screen appears Menu Items Purpose Mark Puts a marker in the time history Settings Modifies the SLM settings for the selected instrument Graph Changes the...

Страница 236: ...wing menu appears When Set Mark is initiated by pressing the Check ckey 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 a...

Страница 237: ...tings 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 uor dkey allow...

Страница 238: ...menu Controls Settings Menu Allows you access to the Settings menu in the Controls area that is usually accessed from the SETUP Skey This is a shortcut to the Controls settings so you can modify the...

Страница 239: ...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...

Страница 240: ...u with a description of each menu item In the Leq Spectrum display press the Check ckey and the following menu appears Graph Changes the scaling of the instru ment s SLM history graph Bandwidth Select...

Страница 241: ...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...

Страница 242: ...the Check ckey while viewing the Run Log display and the following check menu appears Menu Items Purpose Broadband Spec trum Allows you to view the broadband history graph or the spectral data Locate...

Страница 243: ...re 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 Fi...

Страница 244: ...ears 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 th...

Страница 245: ...o 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 percentag...

Страница 246: ...menu 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 Check menu Menu Ite...

Страница 247: ...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 consti tutes 100 dos...

Страница 248: ...ttings for the selected instrument Graph Changes the scaling of the instru ment s Ln b Centiles graph Menu Items Purpose SPL Excd Lvl 1 Sets the lowest SPL trigger level SPL Excd Lvl 2 Set the higher...

Страница 249: ...als 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 Se...

Страница 250: ...a through Excd b the fol lowing menu appears after pressing the Check ckey Following is a chart of the check menu with a description of each menu item In the Excd Time History display press the Check...

Страница 251: ...r pressing the Check ckey 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 specif...

Страница 252: ...th 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 recor...

Страница 253: ...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...

Страница 254: ...nt Print menu available The screen shown is for the SSA instrument Step 2 Press the PPrint key The following screen appears The TAL and FFT instruments do not generate any reports The Print menu provi...

Страница 255: ...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 ena...

Страница 256: ...ry menu item This means that a report will be printed by highlighting Summary and pressing the Check ckey The title printed on your report will correspond to the Title setting you have configured in t...

Страница 257: ...discusses how to define and print tailored reports for the SSA and LOG instruments Selecting Tailored Report under the Print menu copies the report set tings under Define Report from the Setup Menu fo...

Страница 258: ...ect it Step 2 Using the uand darrow keys highlight the Define Report item then select it using the r arrow key or the cCheck key The following screen appears Step 3 Use the uand darrow keys to scroll...

Страница 259: ...G 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 Long and All Short When the summary re...

Страница 260: ...ummary 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 Rec...

Страница 261: ...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...

Страница 262: ...s exceedance and calibration logs Log Report Yes The run stop log and with the date and time of each run stop Setup Report No Print the settings and their values for the LOG instrument SPL Histogram...

Страница 263: ...cord to be printed Highest Record 99999 Selects the highest time history record to be printed Histograms SPL Histogram No You can customize the SPL Histogram report by choosing the long or short repor...

Страница 264: ...d dura tion in the short report The Long reports adds the Ln values and Spectral LNs for the Interval period Hist Report No Leq for each time history period Print Range Intv Report Short You can custo...

Страница 265: ...ultiple 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 lo...

Страница 266: ...me 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 level to b...

Страница 267: ...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...

Страница 268: ...he 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 exceednaces time date and dura tion in the short re...

Страница 269: ...ects 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 Yes Y...

Страница 270: ...est 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 Hist...

Страница 271: ...sing 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 Histogr...

Страница 272: ...max 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 exceednaces time date and dura tion...

Страница 273: ...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...

Страница 274: ...Highest Record 99999 Selects the highest 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 045...

Страница 275: ...modifications For your report to print properly your printer must be connected and configured as discussed earlier in this chapter Step 4 Use the larrow key to completely back out of the Customize men...

Страница 276: ...o Short Long Lowest Record Highest Record Hist Report No Yes Lowest Record Highest Record Histograms SPL Histogram No Yes Lowest Level Highest Level Resolution Pk 1 Histogram No Yes Lowest Level Highe...

Страница 277: ...nge Excd Report No Short Long Lowest Record Highest Record Intv Report No Short Long Lowest Record Highest Record Hist Report No Yes Lowest Record Highest Record Histograms SPL Histogram No Yes Lowest...

Страница 278: ...ate trigger phase ad Max Spectrum Min No Yes Shows beginning and ending date and time runtime type of Averaging sample rate trigger phase ad Min Spectrum Autostore Rpt No Short Long The Short report p...

Страница 279: ...m files The download 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 displayi...

Страница 280: ...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 software wa...

Страница 281: ...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...

Страница 282: ...tton 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 Utility...

Страница 283: ...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 allowthe user to retrieve previously stored s...

Страница 284: ...up 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 butto...

Страница 285: ...gs 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 Ge...

Страница 286: ...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...

Страница 287: ...change any of the parameters for the Title Calibration 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...

Страница 288: ...appro priate tab and enter the changes Manipulating 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 righ...

Страница 289: ...ample 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 u...

Страница 290: ...tup is automati cally 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...

Страница 291: ...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...

Страница 292: ...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...

Страница 293: ...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...

Страница 294: ...24 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 applie...

Страница 295: ...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...

Страница 296: ...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...

Страница 297: ...iles 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...

Страница 298: ...i fied directory now show on the download screen These settings will only apply for the currently selected mea surement NOTE This process will have to be repeated for each measurement to be downloaded...

Страница 299: ...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 repor...

Страница 300: ...ay 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 lis...

Страница 301: ...m 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 bo...

Страница 302: ...n 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 and...

Страница 303: ...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 depending on...

Страница 304: ...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 tr...

Страница 305: ...ile 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 Downloade...

Страница 306: ...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 that...

Страница 307: ...824 Utility Software 9 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...

Страница 308: ...9 30 824 Reference Manual 11 8 00 The default Windows printer dialog box will be displayed The report will be printed in a text format similar to that shown below...

Страница 309: ...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...

Страница 310: ...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...

Страница 311: ...en 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 histo...

Страница 312: ...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...

Страница 313: ...are round the RT60 values to two decimal places However because the 824 uses logrithmic arithmetic to calculate the RT60 value and the 824 Utility software uses double precision to calculate the value...

Страница 314: ...9 36 824 Reference Manual 11 8 00...

Страница 315: ...coustics On board 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 acoust...

Страница 316: ...n to RTA and press the ccheck key The RTA Live view will now be displayed Press the SSETUP key again to return to the SETUP menu At the top of the Setup menu Edit Settings will be highlighted Press th...

Страница 317: ...in 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 Tr...

Страница 318: ...Input 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...

Страница 319: ...oltage 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 anal ysis Detector Setting...

Страница 320: ...terval 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 i...

Страница 321: ...Yes For setups with a linear detector spectra are stored once every linear detector time When an exponential detector is selected samples are stored every exponential detector time multi plied by the...

Страница 322: ...ngs Menu Arm Mode Elapsed time and qualifying times are evaluated only when a new ByTime sample is created This causes the minimum effective time resolution to become the same as the update interval T...

Страница 323: ...level settings If the time is non zero then the level condition must be met for the speci fied time before Arm Mode is entered 00 0000 to 99 9975 seconds Arm Samples When the Arm Mode is set to Count...

Страница 324: ...nput 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 recor...

Страница 325: ...ecord 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 until...

Страница 326: ...stop recording an Autostore record 0 0 255 9 dB End Time 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...

Страница 327: ...at Count Allows the user to select how many times the measurement will repeat when the End Then setting is set to Repeat 0 255 Average Count This is the number of times the measurement is repeated and...

Страница 328: ...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 when asserted and to zero vo...

Страница 329: ...ter on screen as the user moves between filters using the up uand down darrow keys Note If Note ends with a numeral it will be incremented automatically with each spatial average snapshot taken or sto...

Страница 330: ...zed RT60 measurement The RT60 A setup is designed to gather data to measure an RT60 by exciting a room with a steady state noise It is con figured in the following way Detector Linear Detector Time 0...

Страница 331: ...kHz Arm Mode Now Trigger Mode L Trigger Level 80 0 dB Trigger Time 00 0000 seconds End Mode Time End Time 3 0 seconds Then Stop Rooms RTA Instrument Definition The System 824 has an Instrument Defini...

Страница 332: ...ws 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 results and manipulate the data RTA Views The RTA...

Страница 333: ...nd 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 the live spectrum and is the current sampl...

Страница 334: ...ssing the sR 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 T...

Страница 335: ...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 Curren...

Страница 336: ...row key to bring up the View Trigger display view menu The Trigger display view offers 2 choices Status and Setup Use the ccheck key to select the Status display Status The Trigger status display show...

Страница 337: ...cond 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 cCheck key provides quick access to the trigger...

Страница 338: ...record of triggered data that is stored automatically 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...

Страница 339: ...eck key to view the Leq display Leq The autostore 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 ccheck...

Страница 340: ...key twice while in any of these dis play 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 Disp...

Страница 341: ...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 and di...

Страница 342: ...we are cur rently 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...

Страница 343: ...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 ccheck key twice toggling betwe...

Страница 344: ...al Averaging displays and menus are covered later in this chap ter Average Add spectrum to spatial average or view spa tial spectra average If 1 3 octave filters are selected the Rooms display gives y...

Страница 345: ...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 record...

Страница 346: ...feature 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 da...

Страница 347: ...ect routine will automatically locate the cursor to be 5 dB below the maximum level The auto select is exe cuted on demand from the check menu and the first time the RT 60 display is selected There is...

Страница 348: ...Graph 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...

Страница 349: ...ct 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 increment wi...

Страница 350: ...age display 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...

Страница 351: ...patial 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 spatial...

Страница 352: ...eraged 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...

Страница 353: ...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 is ab...

Страница 354: ...ator can show the following Under indicates that Lmf midfrequency 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 Neutra...

Страница 355: ...ed 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 backgr...

Страница 356: ...10 42 824 Reference Manual 11 8 00...

Страница 357: ...ption Features The FFT option has the following features 400 line FFT Hanning or Rectangular window Bandwidths of 200Hz 500Hz 1kHz 2kHz 5kHz 10kHz and 20kHz Count averaging 1 to 16384 Snapshot data st...

Страница 358: ...he FFT settings menu NOTE See Chapter 5 of the 824 Refer ence Manual for a more detailed expla nation on selecting instrument definitions The menu layout of the FFT settings is shown in the table belo...

Страница 359: ...f the micro phone signal This setting provides the following options 20 10 0 10 20 30 40 50 Bandwidth The bandwidth for each line is the bandwidth setting divided by the lines setting With the bandwid...

Страница 360: ...lter leakage or effects of a truncated series The Hanning window minimizes the filter leakage with the cost of a wider main lobe The Flat top window gives better amplitude accuracy in the passband Ove...

Страница 361: ...en measuring with a free field microphone See Appendix C for the random inci dence correction filter s response No Random incidence correction is turned off Yes Random incidence correction is turned o...

Страница 362: ...enu will appear FFT accesses the live FFT spec trum and Snapshot displays the FFT snapshot data With FFT highlighted press the Check ckey to enter the FFT display FFT The FFT display shows a live FFT...

Страница 363: ...ay of the FFT The zoom factor is shown graphically as a horizontal bar at the bottom of the bargraph The shorter the bar the greater the zoom The location of the zoom bar indicates the position of the...

Страница 364: ...he THD as calculated in the 824 satisfies all of the requirements for ANSI S3 6 THD Activates the THD display which shows the cal culated THD Settings Activates the FFT settings menu Graph Adjusts the...

Страница 365: ...ency then finding the nearest bin frequency and summing its level with it s side band levels The third harmonic is found by tripling the fundamental frequency then finding the nearest bin frequency an...

Страница 366: ...dB above the noise floor the level of the harmonic is marked with an asterisk The noise floor is calculated as the maximum of the mini mum in the two adjacent valleys If one of the harmonic s side ba...

Страница 367: ...Snapshot and press the Check ckey to access the snapshot data Use the up uand down darrow keys to scroll through each record Use the check menu to control the HORIZONTAL SCALE The date and time record...

Страница 368: ...cale Allows numerical entry of graph scale Zoom in Allows you to see FFT spectrum with more detail See page 6 for more information Zoom out Allows you to see FFT spectrum with less detail See page 6 f...

Страница 369: ...ulated using the following formula 26 0 dB 20Log 1 volt 0 05V Enter 26 0 dB into the menu item Linear Scale for the correct scale level The accuracy of the linear units value is 5 of the true value Th...

Страница 370: ...ion Linear Units This is the unit entered by the user in the menu for Linear Units In this particular case we have entered g for acceleration Frequency shown by cursor This is the frequency as shown b...

Страница 371: ...11 2 00 FFT Optional 11 15...

Страница 372: ...11 16 824 Reference Manual 11 2 00...

Страница 373: ...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...

Страница 374: ...AUDTest AUD setup Press the check key to retrieve the current setup and enter the audiometer calibration mode The SLM RTA Live screen will appear This screen shows the third octave spectrum In this ex...

Страница 375: ...s the default screen for the AudTest AUD setup To access this display press the VIEW key then select the SLM RTA with the up down arrows and press the check key To measure the level in dB re 20 microp...

Страница 376: ...selecting the SLM RTA with the up down arrows and press the check key Once in the SLM RTA Live screen press the up or down arrow to display the Any Level a screen This screen displays the current Fast...

Страница 377: ...ements harmonic distortion narrow and broad band noise frequency linearity crosstalk This mode consists of three screens FFT THD and Linear ity FFT Screen To access the FFT screen press the VIEW key t...

Страница 378: ...ace the cursor on the frequency of interest and read the frequency and value on the left hand side of the screen In this mode levels must also be corrected by using coupler earphone RETSPLs and microp...

Страница 379: ...the fundamental bin frequency and the highest sideband bin frequency The sec ond harmonic is found by doubling the fundamental fre quency then finding the nearest bin frequency and summing its level w...

Страница 380: ...fiable tone The fundamental frequency will be displayed whether there is an identifiable tone or not If a harmonic is less than 10 dB above the noise floor the level of the harmonic is marked with an...

Страница 381: ...s an audiometer To access the linearity screen press the VIEW key high light FFT with the up down arrows and press the right arrow key This will display the sub menu of the FFT screen Use the the up d...

Страница 382: ...Fun damental level always shows the actual dB level coming into the 824 To set the incoming signal as the reference press the check key to enter the Linearity check menu You may also enter the refere...

Страница 383: ...will see the Fundamen tal reference level change Usually audiometers have steps of 5 or 10 dB You can also see the effect frequency has on the accuracy of the amplitude linearity by varying the fre q...

Страница 384: ...lues displayed Rise Time B C time in milliseconds between the 20 dB point referred to the maximum level and 1 dB point on the rising edge of the pulsed signal envelope nomi nally between 20 and 50 ms...

Страница 385: ...l 12 13 Plateau or Pulse Width C E duration in milliseconds of the plateau during which the signal is within 1 dB of its nominal value Overshoot Lov the level in dB that the signal rises above the nor...

Страница 386: ...uired values for the calibration of the frequency modulated tone capabilities of an audiometer Present the frequency modulated tone at an appropriate level and press the RUN STOP key The stability of...

Страница 387: ...allows you to change the gain The gain choices available are 20 10 0 10 20 30 40 50 See page C 13 of Appendix C for a table showing the response of the A weight and C weight high pass fil ters You can...

Страница 388: ...12 16 824 Reference Manual 11 8 00...

Страница 389: ...ure level is defined as follows where L Aeq T is the equivalent continuous A weighted sound pres sure level re 20 Pa determined over a time interval T t 2 t 1 p A t is the instantaneous A weighted sou...

Страница 390: ...buting to the measurement The titles for the measurements are designed to indicate the current exchange rate in force Leq is used to designate TWAs based upon a 3dB exchange rate LDOD for United State...

Страница 391: ...y is A weighted and has a measurement elapsed time of 11 43 1 11 hours 43 minutes and 1 second The actual equations used within the analyzers are based on that for IEC 804 and are implemented accordin...

Страница 392: ...nd Lcal is the calibration offset that corrects for various sensitiv ities of microphones Accuracy is maintained by having large fixed point variables for the number of samples and the summation accum...

Страница 393: ...9 12 00 A 5 The following data indicates which settings are associated with which TWA data variables...

Страница 394: ...History HNL IO Command R59 Daily Runtime unavailable Always 3dB Exchange Rate No Threshold Reset at the end of the current hour or a RES ALL Exceedance History TWA EXCD a EXCD c Exceedance Report IO C...

Страница 395: ...standards or govern ments require SEL to be taken without a Threshold set it to zero and with an Exchange Rate of 3dB Dose and Projected Dose Calculations Dose is a measure of Sound Exposure and is de...

Страница 396: ...ate in dB and q the parameter that determines 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...

Страница 397: ...hour times 60 seconds minute 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 t...

Страница 398: ...A 10 824 Reference Manual 9 12 00...

Страница 399: ...rt Data can also be downloaded to and settings queried and set by the controlling computer The System 824 may be connected to the computer directly or through a modem A network of many instruments can...

Страница 400: ...in configurations for the CBL006 follow 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 LaserJet 9 pin m...

Страница 401: ...ever an address byte is received only the corresponding instrument is enabled to receive and respond to commands A broadcast command can be sent By sending an address of zero CHR 128 all units on the...

Страница 402: ...break is sent 124 Address 124 FC Auto ID will initiate an Auto Identification of all 824s on the net using a timing scheme based on each unit s address The data received will be the address byte from...

Страница 403: ...knowledge 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 Error Checki...

Страница 404: ...ent Sound Pressure Level without accumulating data M6 or M6 0 Set standard mark M6 1 Set mark 1 Aircraft M6 2 Set mark 2 Automoble M6 3 Set mark 3 Truck M6 4 Set mark 4 Train M6 5 Set mark 5 Animal M7...

Страница 405: ...4 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 diagnost...

Страница 406: ...nd 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 2 megabyte...

Страница 407: ...acter is the 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 det...

Страница 408: ...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 R9 w LOG Overal...

Страница 409: ...M 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 nnn n dB R28 w LOG OverAll Luwpk Date and Time ddmmmyy hh mm...

Страница 410: ...t 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 Overall Leq nnn n dB R 58 LOG Dail...

Страница 411: ...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 nnnnnnn R92 LOG Number of RUN STOP Records nn...

Страница 412: ...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 Intv Ex...

Страница 413: ...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 SSA LOG...

Страница 414: ...detector level nnn nn dB R155 ALL Number of Bytes in Keyboard Stack This is used with keyboard simulation to prevent the loss of keys nnn R156 LOG Background Leq Time hhhhh mm ss ss R157 ALL Calibrati...

Страница 415: ...is ANSI filter cccccHz R175 ALL OverAll End Date and Time ddmmmyy hh mm ss R176 ALL Current End Date and Time ddmmmyy hh mm ss R177 ALL OverAll Reset Began Text Reset or Began R178 ALL Current Reset...

Страница 416: ...re quency nnnnn nn R200 AUD Audiometric Test Max Frequency nnnnn nn R201 AUD Audiometric Test Min Frequency nnnnn nn R202 AUD Audiometric Test Modulation Fre quency nnnnn nn R203 l AUD FFT Live Spectr...

Страница 417: ...n R217 RTA Triggered ByTime Samples R218 n RTA Triggering String n 1 2 ARM 3 4 Trig 5 6 End 7 Repeat 21 character string 0 all strings character string R219 f RTA Spatial Averaged Spectrum f ANSI filt...

Страница 418: ...Tonal Group Level nnn n R231 TAL Tonal Background Level nnn n R232 TAL A weight Impulse Leq Overall nnn n R233 TAL Tonality Run Time hh mm ss R233 LOG Excd Duration mm ss ss R234 f SSA Ln 1 Spectrum...

Страница 419: ...nly R 4 x SSA ISM LOG Current SPL Any Wght Dect nnn n dB R 9 w SSA ISM LOG OVERALL TWA Any Wght nnn n dB R 11 w SSA ISM LOG CURRENT TWA Any Wght nnn n dB R 13 w SSA ISM LOG OVERALL SEL Any Wght nnn n...

Страница 420: ...23 w SSA ISM LOG OverAll Pk Level Any Wght nnn n dB R 24 w SSA ISM LOG OverAll Lpk Date and Time Any Wght ddmmmyy hh mm ss R 25 w SSA ISM LOG Current Pk Level Any Wght nnn n dB R 26 w SSA ISM LOG Curr...

Страница 421: ...fined macro which is programmed by the Group command Group Read Programming The group command permits the programming of a user defined macro with up to eight 8 Read variables The 1 A weight 2 C weigh...

Страница 422: ...G0 is 59 5 38 6 102 2 the SPL Lmin and Lmax Setting Commands The Settings select what functions are enabled and deter mine how the measurements are performed Settings can be both set S and queried Q...

Страница 423: ...e Brackets indicate optional characters or operands cr carriage return lf line feed _ space Option flags elicit the following responses Flag values may be added together for desired combinations Synta...

Страница 424: ...g_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 settings 4 Q74 32...

Страница 425: ...aracters that are given when queried including spaces which are indicated below with __ Syntax Response S et item_number option_number cr lf Example S9 3 sets setting 9 Baud Rate to option 3 which set...

Страница 426: ...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 Respo...

Страница 427: ...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...

Страница 428: ...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...

Страница 429: ...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...

Страница 430: ...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...

Страница 431: ...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...

Страница 432: ...RTAf 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 T...

Страница 433: ...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...

Страница 434: ...ds 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 VALUE n S107 LOG SPL HI...

Страница 435: ...T 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 Han ning S148 SSA RTA FFT AUD INT RTA Gain Range contro...

Страница 436: ...6 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 LOG R S AND CAL LOG x S179 ALL SETUP...

Страница 437: ...O 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 RTAf PRINT MIN SUMMARY OR EVENT DATA NO YES S192...

Страница 438: ...racter for the S205 0 command A detailed description of the protocol is available from Lar S197 SSA ISM LOG INTV REPORT HIGHEST RECORD n S198 LOG HIST REPORT x S199 LOG HIST REPORT LOWEST RECORD n S19...

Страница 439: ...icrophone sensitivity An equivalent microphone capacitance can be used after calibration to determine the noise floor It may also be possible to remove the microphone bias to obtain this value When pr...

Страница 440: ...S227 ALL OVERALL CALIBRATION OFFSET uses 225 48 lock S230 ALL BIAS OFFSET For High Range Cali bration uses 225 48 lock S231 Reserved setting S232 ALL Temperature Calibration Cal level must be 225 48 S...

Страница 441: ...No Yes S63 RTA Arm Mode L L Input Time Count S64 RTA Arm Level nnn n dB S65 RTA Arm Time ss ssss Sec for Level and Time Arm Mode Conditions S66 RTA Arm Samples nnnnn S67 RTA Arm Logic Input TRUE Level...

Страница 442: ...peat Average S82 RTA Repeat Count nnn 0 to 255 times S83 RTA Average Count n 0 to 9 times S84 RTA Annunciator cccccccc if right digit is numeric it will auto increment S85 RTA RT 60 calculation dB dow...

Страница 443: ...defined in the history_number column below The Advance and Backup commands are generally used next They extract data after the initial find command The Find command takes longer to execute as the reco...

Страница 444: ...can be identified explicitly with the Advance Backup and 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...

Страница 445: ...tional characters and oper ands 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 calibration...

Страница 446: ...5 LOG Lmax nnn n dB E5 f RTA Min Filter E6 LOG Lpeak nnn n dB E6 RTA Overload E7 LOG UnWeighted Peak nnn n dB E7 RTA Pretrigger Samples E8 LOG Peak Exceedance Count nnn E8 RTA Trigger Samples E9 LOG O...

Страница 447: ...le Duration E15 n RTA By Time Overload E16 RTA RT60 calculation at current filter Filter set by E 3 E 4 E 5 or E 12 E17 LOG Excd Time Hist Samples nnn E17 n RTA Extracts ByTime History and returns not...

Страница 448: ...hh means any hour and the hh m means any hour and tens of minutes All subsequent intervals will now be synchro nized to the real time clock Syntax Response I nterval var_no Intv_var Examples I 1 I 1...

Страница 449: ...veraged nnnn I2 FFT Count nnn I3 SSA LOG TWA nnn n dB I3 RTA Spectral or Flat Level n ANSI filter nnn n dB I3 FFT OVER LOAD cccc I3 TAL Overload Counts nnn I4 SSA LOG SEL nnn n dB I4 RTA Note Field cc...

Страница 450: ...Percent nn I16 LOG Intv Ln 2 Level dB nnn n I17 LOG Intv Ln 3 Percent nn I18 LOG Intv Ln 3Level dB nnn n I19 LOG Intv Ln 4 Percent nn I20 LOG Intv Ln 4 Level dB nnn n I21 LOG Intv Ln 5 Percent nn I22...

Страница 451: ...A LOG Intv Ln 1 Percent nn I11 SSA LOG Intv Ln 1 Level dB nnn n I12 SSA LOG Intv Ln 2 Percent nn I13 SSA LOG Intv Ln 2 Level dB nnn n I14 SSA LOG Intv Ln 3 Percent nn I15 SSA LOG Intv Ln 3 Level dB nn...

Страница 452: ...5 TAL Ftone nnnnn Hz I6 TAL Dfc nnnnn Hz I7 TAL Ltone nnn n dB I8 TAL Lgroup nnn n dB I9 TAL Ltone Lgroup nnn n dB Syntax Response D aily var_no hour daily_var Example D5 5 hourly noise level for hour...

Страница 453: ...nn n D 22 LOG Intv Ln 2 Percent nn D 23 LOG Intv Ln 2 Level dB nnn n 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...

Страница 454: ...esponse L og var_nolog_var Example L1 Run Stop number L 1 Run Stop Number nnnnn L 2 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...

Страница 455: ...LOG TAL Return the advanced value where n comes from a list of available levels The optional parameter n is available only when advanced time history is enabled When n is omitted or 0 all enabled val...

Страница 456: ...nd oper ands Histogram Table Variables Brackets in the syntax indicate optional characters and oper ands Table 1 RMS 2 Peak 3 Unweighted Peak H 101 SSA LOG TAL Same as doing an H 1 H 5 0 H 102 SSA LOG...

Страница 457: ...f current bin nnn n dB T 2 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...

Страница 458: ...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...

Страница 459: ...d a file to be viewed in 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...

Страница 460: ...ernal 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 141 Overall Reset Required 142 OPEN 143 Al...

Страница 461: ...ine 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 165 ID is Act...

Страница 462: ...s the Model 824 will dial the Phone on the events selected by the Dial Out Mode defined below Dial Out Mode None The Model 824 will not dial a computer for any reason Excd The Model 824 will dial a co...

Страница 463: ...e Model 824 modifies its baud rate to that of the connected modem If the connection is unsuccessful the procedure is retried in 4 min Step 4 The Model 824 sends the following announce ment 824 824A012...

Страница 464: ...The modem informs the Model 824 that a connec tion has been requested that is the phone is ring ing Step 2 The Model 824 answers the phone Modem sends 824A0123 001 0 Step 3 The modem informs the Mode...

Страница 465: ...are and are docu mented here on an as is basis for those who may desire to explore unaided these advanced features The operation of these commands is subject to change with out notice of any kind X 16...

Страница 466: ...amping of the 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...

Страница 467: ...ing the K is required before non numeric operands i e K 6 The keyboard buffer will hold up to 8 keys K12345678 is acceptable F102 Recall a FILE into active memory F103 Store the current data in active...

Страница 468: ...is High the 824 takes data and if 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...

Страница 469: ...for all System 824 s using the following options PRM902 preamp 2541 or 2560 free field or random high sensitivity microphones 2540 or 2559 free field or random normal sensitivity microphones NOTE Not...

Страница 470: ...cable CBL042 AC DC output cable CBL002 serial interface cable is in accordance with the following directives 89 336 EEC The Electromagnetic Compatibility Direc tive and its amending directives has bee...

Страница 471: ...ble Histogram tables Direct report printouts to laser printer WindowsTM based software for setup control and high speed data download and reporting Advanced WindowsTM based software packages optional...

Страница 472: ...Change Press the check 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 and press the check key The 8...

Страница 473: ...ower input 6 15 Volts at 1 amp max Typical DC power 150 mA 12 Volts DC power connec tor 5 5mm x 2 5mm coaxial power plug Physical Characteristics Length 9 9 inches 25 1 cm Width 3 4 inches 8 6 cm Dept...

Страница 474: ...preamp Frequencies to 20 kHz 700 feet 213 meters Frequencies to 10 kHz 1000 feet 305 meters Maximum RMS Voltage Input Gain VRMS Vp p dBuV 0 dB 4 24 6 00 135 6 10 dB 1 34 1 9 125 6 20 dB 0 42 0 60 115...

Страница 475: ...6 0 0 0 4 0 6 400 398 10 0 0 4 8 0 0 0 4 0 6 500 501 20 0 0 3 2 0 0 0 4 0 6 630 631 00 0 0 1 9 0 0 0 4 0 6 800 794 30 0 0 0 8 0 0 0 4 0 6 1000 1000 00 0 0 0 0 0 0 0 4 0 6 1250 1259 00 0 0 0 6 0 0 0 4...

Страница 476: ...ng AC 1 AC 2 Flat AC output Flat AC output with 30dB gain AC 1 DC Flat AC output Weighted DC output AC 1 DC Flat AC output with 30 dB gain Weighted DC output AC 2 AC 1 Flat AC output with 30 dB gain F...

Страница 477: ...ormal 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 0 108 0 48 0 SSA Mod...

Страница 478: ...dB 0 4 dB typical Flat frequency range 10 Hz 20 kHz rela tive attenuation 0 15 dB Filter type Digital Octave frequency ratio Base 2 See IEC 1260 Annex A AC DC Output SSA mode only 824 Menu 3 5mm Conne...

Страница 479: ...3 118 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 70 250 3 37 128 91 3 25 118 93 3 15 108 93 4 15 98 83 10 8 88 80 9 8 78 70 50...

Страница 480: ...specifications page D 8 400 Line FFT Overshoot computation Overshoot is calculated as the maximum sam ple level minus the averaged ON level Measurement condi tions Conditions that must be met to produ...

Страница 481: ...2 1 4 63 63 50 0 0 28 2 0 9 80 80 00 0 0 24 5 0 6 100 100 80 0 0 21 1 0 4 125 127 00 0 0 18 1 0 2 160 160 00 0 0 15 3 0 1 200 201 60 0 0 12 8 0 1 250 254 00 0 0 10 6 0 1 315 320 00 0 0 8 6 0 0 400 403...

Страница 482: ...Reference level range 0 dB gain Sample rate 51 200 Hz 1 3 octave band fre quencies 12 5 Hz 20 kHz 33 fil ters 1 1 octave band fre quencies 16 Hz 16 kHz 11 octaves Filter integrated response 0 15 dB f...

Страница 483: ...8 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 15 108 93 5 13...

Страница 484: ...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 added to the measured data when using the Larson Davis M...

Страница 485: ...9 13 00 C 17 Windscreen Corrections...

Страница 486: ...provide random incidence response when measuring with a free field microphone NOTE Tested with the preamplifier and microphone attached directly to the 824 The graphs below show the response of the f...

Страница 487: ...Graph 2 The 824 in normal range with the 2540 free field microphone showing the corrected random response Graph 3 The 824 in normal range with the 2541 free field microphone showing the uncorrected ra...

Страница 488: ...C 20 824 Reference Manual 9 13 00 Graph 4 The 824 in normal range with the 2541 free field microphone showing the corrected random response...

Страница 489: ...with the LCD facing up for these tests The following graphs show the effects on the performance of the 824 caused by the following Windscreen Instrument Case High Range NOTE The graphs below show typi...

Страница 490: ...C 22 824 Reference Manual 9 13 00 Graph 2 The 824 in normal range with the 2540 micro phone and windscreen Graph 3 The 824 in high range with the 2540 microphone...

Страница 491: ...9 13 00 C 23 Graph 4 The 824 in high range with the 2540 microphone and windscreen Graph 5 The 824 in normal range with the 2541 micro hpone...

Страница 492: ...C 24 824 Reference Manual 9 13 00 Graph 6 The 824 in normal range with the 2541 micro phone and windscreen Graph 7 The 824 in high range with the 2541 microphone and windscreen...

Страница 493: ...s tested in two different configurations as fol lows 824 oriented with the LCD facing up 824 oriented on it s side Definitions The XY plane is defined as the 824 oriented with it s LCD facing up The Y...

Страница 494: ...C 26 824 Reference Manual 9 13 00 Graph 2 824 in the XY plane fitted with the 2540 micro phone 2kHz Graph 3 824 in the XY plane fitted with the 2540 micro phone 4 kHz...

Страница 495: ...9 13 00 C 27 Graph 4 824 in the XY plane fitted with the 2540 micro phone 8 kHz Graph 5 824 in the XY plane fitted with the 2540 micro phone 12 5 kHz...

Страница 496: ...C 28 824 Reference Manual 9 13 00 Graph 6 824 in the YZ plane fitted with the 2540 micro phone 1 kHz Graph 7 824 in the YZ plane fitted with the 2540 micro phone 2 kHz...

Страница 497: ...9 13 00 C 29 Graph 8 824 in the YZ plane fitted with the 2540 micro phone 4 kHz Graph 9 824 in the YZ plane fitted with the 2540 micro phone 8 kHz...

Страница 498: ...C 30 824 Reference Manual 9 13 00 Graph 10 824 in the YZ plane fitted with the 2540 micro phone 12 5 kHz Graph 11 824 in the XY plane fitted with the 2541 micro phone 1 kHz...

Страница 499: ...9 13 00 C 31 Graph 12 824 in the XY plane fitted with the 2541 micro phone 2 kHz Graph 13 824 in the XY plane fitted with the 2541 micro phone 4 kHz...

Страница 500: ...C 32 824 Reference Manual 9 13 00 Graph 14 824 in the XY plane fitted with the 2541 micro phone 8 kHz Graph 15 824 in the XY plane fitted with the 2541 micro phone 12 5 kHz...

Страница 501: ...9 13 00 C 33 Graph 16 824 in the YZ plane fitted with the 2541 micro phone 1 kHz Graph 17 824 in the YZ plane fitted with the 2541 micro phone 2 kHz...

Страница 502: ...C 34 824 Reference Manual 9 13 00 Graph 18 824 in the YZ plane fitted with the 2541 micro phone 4 kHz Graph 19 824 in the YZ plane fitted with the 2541 micro phone 8 kHz...

Страница 503: ...9 13 00 C 35 Graph 20 824 in the YZ plane fitted with the 2541 micro phone 12 5 kHz...

Страница 504: ...C 36 824 Reference Manual 9 13 00...

Страница 505: ...ange Rate The equation for it is where Lc is the Criterion Level Tc is the Criterion Duration Q is the Exchange Rate K is the Exchange Rate Factor and Lavg is the Average Sound Level Example If Lc 90...

Страница 506: ...urs from 10 p m to midnight The levels for the hourly periods between 7 p m and 10 p m have 5 added to them to represent a lessened tol erance for noise during evening activities They are energy summe...

Страница 507: ...nd Level DNL Ldn A rating of community noise exposure to all sources of sound that differentiates between daytime and nighttime noise exposure The equation for it is The continuous equivalent sound le...

Страница 508: ...unit free and therefore the dB value is not the value of the quantity itself but the ratio of that quantity to an actual reference quantity used Thus for every level in decibels there must be a well...

Страница 509: ...es by 3 dB the sound power value is multiplied by 2 Thus it is important to notice 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 dou...

Страница 510: ...in equation D 1 below Table 2 illustrates 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...

Страница 511: ...l 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 Standard ANSI S12 1...

Страница 512: ...e from a 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 w...

Страница 513: ...dpass A frequency filter that permits signals to pass through that have frequencies above a certain fixed fre quency called a lower cutoff frequency and below a certain fixed frequency called an upper...

Страница 514: ...ing is seldom 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 o...

Страница 515: ...s to hearing dam age 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 the changi...

Страница 516: ...usted 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...

Страница 517: ...ng measured The microphone measures very small forces low level sound can run about one billionth of a PSI Every measurement instru ment changes the thing being measured and for very small forces that...

Страница 518: ...e acous tic near field is characterized by pressures that do not create sound that can be measured in the far field Therefore mea surements made here are not useful in predicting the sound levels far...

Страница 519: ...by the Criterion Duration and by the sound level the higher the level the shorter the allowed time The sound levels must be measured with A frequency weighting and slow exponential time weighting See...

Страница 520: ...defined as unwanted sound It can also be defined as sound that causes adverse effects on people such as hearing loss or annoyance It can also be defined as the sound made by other people In every cas...

Страница 521: ...g sound pressure and is measured in Pascals Pa Newtons per square meter which is a metric equivalent of pounds per square inch To measure sound the oscillating pressure must be separated from the stea...

Страница 522: ...ound pressures in all time intervals are equally weighted Sound Pressure Level SPL Lp The logarithmic form of sound pressure It is also expressed by attachment of the word decibel to the number The lo...

Страница 523: ...ixed time period that has the same sound energy as the actual time varying sound over the same period This descriptor is widely used It is a fixed average See Sound Pressure Impulse The value of an im...

Страница 524: ...physical motion of the medium itself Spectrum Frequency Spectrum The amplitude of sound or vibration at various frequencies It is given by a set of numbers that describe the amplitude at each frequen...

Страница 525: ...es in sound level more rapidly Impulse The time constant is 35ms for the rise and 1 5 sec onds 1500 ms for the decay The reason for the double con stant is to allow the very short signal to be capture...

Страница 526: ...he 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 fre quency in Hz and is the radian frequency It has...

Страница 527: ...t 6 8 Any Level Format 6 7 Any Level a Screen 12 4 Any Time Format 6 8 Arm Level 10 9 Arm Logic In 10 9 Arm Mode 10 8 Arm Samples 10 9 Arm Settings Menu 10 8 Arm Time 10 9 Arrow Keys 3 11 Autostore 10...

Страница 528: ...mputer B 2 Connector AC DC Output connector 1 9 Control Connector 1 8 Serial Connector 1 9 Control connector 1 8 Control keys 3 2 Conventions Formatting 1 3 Creating a New Setup 9 14 Criterion D 2 sou...

Страница 529: ...I O B 40 Error Messages B 61 Excd 7 70 Exceedance Enable 7 32 Exceedance History Display 6 49 Exceedance History Variables B 47 Exceedance Time 7 33 Exceedance Time History 7 33 Exceedance Time Histor...

Страница 530: ...val History 5 7 Interval History Variables B 49 Interval Period 7 29 Interval Report 7 36 Interval Save Ln s 7 30 Interval Spectral Lns 6 14 Interval Spectrum 7 32 Interval Threshold 7 31 Interval Tim...

Страница 531: ...36 Modem Mode 3 35 Modifying and Storing Setups to the 824 9 9 Modifying IDs 4 10 Modifying Instrument Definitions 3 28 Modifying the settings menu 4 16 N Navigation keys 3 2 Near Field acoustic D 12...

Страница 532: ...source external 1 15 Preamplifier D 14 Preamplifier input connector 1 10 Preparing for a Measurement 4 14 Pretrigger 10 7 Preview 3 11 Print commands B 59 Print Commands B 59 Print Key 3 36 Printing...

Страница 533: ...Files 9 12 SEL A 7 SEL Calculations A 7 Selecting a Data set to view 9 27 Selecting a Measurement Setup 2 5 Selecting a VIEW 2 11 Selecting IDs 4 10 Selecting the 824 AUD Operation Mode 12 2 Serial A...

Страница 534: ...easurements 2 7 Storing Data 2 13 4 5 Storing Setups to the 824 9 9 System 1 7 1 11 System 824 1 7 System Diagram 1 10 1 11 System Settings 9 9 T Tabular RTA Views 6 11 Tailored Report B 37 Taking Mea...

Страница 535: ...alibration history B 56 daily history B 54 exceedance history B 47 histogram B 58 histogram table B 58 interval B 49 interval history B 49 run log B 56 time history B 57 Vibration D 19 View choices 2...

Страница 536: ...824 Reference Manual x...

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