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Ngara

User Manual

7.7.2 Directional Response

The directional characteristic of a microphone is a measure of its differing sensitivity for sound waves arriving from
various angles. Since the pre-polarised condenser microphone used in Ngara is a pressure sensitive type, it should be

equal in all directions. However, refraction and cavity effects cause a certain microphone directional response at high
frequencies.

Figure 43 shows the directional response for the UC-53A microphone.

Figure 43: UC-53A Directional Response

7.7.3 Thermal Characteristics

The thermal characteristics of a microphone include indicate how sensitivity changes at various temperatures. This

is influenced by the choice of materials and the design of microphone. Normally materials with a linear expansion
coefficient are used.

Figure 44 shows the thermal characteristics of a UC-53A microphone at 250Hz.

Version — 25-7cd7566

Page — 74 of 80

Содержание Ngara

Страница 1: ...Ngara User Manual 25 7cd7566...

Страница 2: ...e 834b25f 2018 04 18 Juan Aguero Move images to images folder d3798ae 2018 03 05 Juan Aguero Add application history 15aafc7 2018 03 05 Juan Aguero Merge branch master of git lab ngara logger wiki 211...

Страница 3: ...ns 11 3 Functions 13 3 1 Standalone Logger 13 3 1 1 Storage Handling 13 3 1 2 Storage Power 13 3 1 3 Session Directory 14 3 1 4 Data Usage 16 3 2 Noise Cloud 17 3 2 1 Communication 17 3 2 2 Modem Powe...

Страница 4: ...libration 28 4 4 7 USB Power 28 4 4 8 Keep Alive 29 4 4 9 Factory Default 29 4 4 10 Exit 30 4 5 Logging Menu Item Menu 2 30 4 5 1 Start Session 30 4 5 2 Stop Session 31 4 5 3 Take Ref 31 4 5 4 Change...

Страница 5: ...8 5 Exit 40 4 9 Status and Idle Screen 40 5 Remote Operation 42 5 1 Installation of Host Software 42 5 2 Main Screen 43 5 3 Linking to a logger 43 5 3 1 The Result Group 44 5 3 2 The Status Group 44 5...

Страница 6: ...5 10 3 Remotely Formatting a USB Drive 66 5 10 4 Performing Statistical Analysis 66 5 10 5 Re constitution of wave file data 67 5 10 6 Reformatting a USB Device 68 6 Network Configuration Options 69 6...

Страница 7: ...2 Directional Response 74 7 7 3 Thermal Characteristics 74 7 7 4 Humidity Characteristics 75 7 7 5 Reduction of Wind Noise by Windscreen 75 7 7 6 Specifications 76 7 8 Filter Responses 76 8 Applicati...

Страница 8: ...Simple control and configuration of Ngara can be accomplished through the on board Liquid Crystal display LCD and push button interface More advanced control functions are made available through the r...

Страница 9: ...configurable battery sizes include 24Ahr Allows for up to a maximum of 2 weeks of continual CSV data only logging and up to 1 week worth of CSV and WAV file data recording 12Ahr Allows for up to a ma...

Страница 10: ...V Output Connector Provided as standard on Ngara Black systems Data will be lost if the storage device is removed during a logging session Please refer to Section 4 5 4 for details on ensuring there i...

Страница 11: ...3A Rion microphone attached to a NH 17 with 5 metre cable preamplifier These components comply with the specifications of AS 1259 and IEC 61672 and as such are highly sensitive Whilst they have some r...

Страница 12: ...d pull apart we recommend dipping the post screws in a lubricant such as Vaseline This makes the posts easier to screw into each other and it also stops them from becoming stuck after being left in th...

Страница 13: ...tation of the file system does not occur To increase disk performance Ngara will not allow the use of a disk which has had sessions deleted It is recommended not to delete sessions from drives but rat...

Страница 14: ...data is stored into 3 1 3 1 Session Log File Session information messages along with any session errors are displayed within the log file Ngara maintains a copy of this log file in its internal memory...

Страница 15: ...to 900 This is required in order to avoid the current Operating System limitation of 999 files per directory It may possible to reach this limitation during a triggered recording session 3 1 3 3 1 CSV...

Страница 16: ...are shown in Table 5 Table 5 PCM Configuration Options Option Fs bit depth Auto ranged OFF 48kHz 48kHz 16 bit Yes 12kHz 12kHz 16 bit Yes 12k 8 12kHz 8 bit No NCam 48kHz 16 bit No PCM data must be reco...

Страница 17: ...unications to the Noise Cloud server This can be interfaced through a modem for a completely remote installation or to a local area network as available The connection type can be updated using the on...

Страница 18: ...on Setting Ancillary Timeout Allow to turn off Ethernet devices Enabled Alarm Clock Set to Keep Alive Ensures Ngara is still on at 7am each day Enabled AUX Output Set to Follow Ethernet Ensures the AU...

Страница 19: ...update Check Started Section 4 8 1 Check Upload Rate Section 4 8 4 Force upload using Wakeup button Ensure service light on modem flashes Ensure Ethernet light on Ngara flashes Ensure Ngara connectivi...

Страница 20: ...gara is configured to use a modem for connectivity it will wait for valid network registration before trying to contact the email server When configured to use a modem but instead is incorrectly conne...

Страница 21: ...es These files are rotated every hour on top of the hour with filenames corresponding to the time and date The filenames are distinguished from the all pass result files with a bpv file extension When...

Страница 22: ...ustrial Noise Monitor mode These are in addition to those listed in Section 3 1 4 Table 13 Industrial Noise Monitor Additional Data Usage CSV Data PCM Data PCM Fs kHz PCM bit depth Usage GB Y N A N A...

Страница 23: ...ll through menu items An ENTER push button Used to select menu items 4 2 Powering the Unit To turn Ngara on press and hold the wake up button until NGARA or a firmware version identifier is displayed...

Страница 24: ...use To change the current timeout settings the following steps must be carried out 1 Activate menu item by pressing ENTER 2 Ngara will display current setting 3 Toggle setting using SELECT 4 Confirm...

Страница 25: ...address currently configured for the Ngara To view currently assigned IP address the following steps must be carried out 1 Activate menu item by pressing ENTER 2 Ngara will display current setting If...

Страница 26: ...ch digit must be entered separately selected digit is shown by cursor Pressing SELECT will increase selected digit by one Pressing ENTER will confirm current digit and move to next digit 4 Once the fi...

Страница 27: ...be entered first followed by the time Time is entered as a 24hr value 4 Each allowable number must be entered separately selected number is shown by cursor Pressing SELECT will increase selected numb...

Страница 28: ...the following steps must be carried out 2 Activate calibration mode by pressing ENTER 3 Ngara will wait until the expected level is entered using SELECT and ENTER Pressing SELECT increases the value o...

Страница 29: ...nt timeout settings the following steps must be carried out 1 Activate menu item by pressing ENTER 2 Ngara will display current setting 3 Toggle setting using SELECT 4 Confirm selection by pressing EN...

Страница 30: ...give the ability to update settings which will affect USB recording opera tions 4 5 1 Start Session This menu item starts a logging session As this session is started through the local interface inste...

Страница 31: ...as been cleared the LCD will return to the top level menu item This menu item is only accessible when a USB session is running 4 5 3 Take Ref This menu item allows the recording of a reference level T...

Страница 32: ...r then has 10 seconds to swap the USB storage device 4 Ngara then checks the new USB storage device to determine if it is useable A session error will be displayed on the LCD if the USB storage device...

Страница 33: ...Disable triggering without the need for a valid IP connection To enable or disable triggering the following steps must be carried out 1 Activate menu item by pressing ENTER 2 Ngara will display curren...

Страница 34: ...manner the USB log files are stored The internal log files will be moved to a directory named Incomplete Log Files within the USB drive the directory will be created if it does not exist To flush int...

Страница 35: ...enu screen Pressing SELECT has no effect Pressing ENTER will exit This display is updated once a second 4 6 3 Max SPL Displays maximum SPL for both A and C weighted level An overload condition is indi...

Страница 36: ...SELECT will reset the display Pressing ENTER will exit This display is updated once a second This menu item is not accessible when operating in Industrial Noise Monitor mode 4 6 7 Filtered SPL Display...

Страница 37: ...Useable disk found Format Required Unusable disk found Within this menu screen Pressing SELECT has no effect Pressing ENTER exits the menu item 4 7 2 List Sessions Displays current saved sessions foun...

Страница 38: ...ice 4 8 1 Start This menu item starts a Noise Cloud logging session To start a Noise Cloud session using the LCD the following steps must be carried out 1 Activate menu item by pressing ENTER 2 Once t...

Страница 39: ...ra will display current setting 3 Increase selected percentile value using SELECT 4 Confirm value using ENTER 5 Continue until all 5 percentiles are confirmed Leq Lmin and Lmax are calculated by defau...

Страница 40: ...shown in Table 20 Table 20 Status Screens Name Description Example Version Current firmware version Ver Vxx x x Serial Unit serial number Serial 878xxx Time and Date Current time and date DD MM hh mm...

Страница 41: ...on failure WARN Config Watchdog Reset An unrecoverable error occurred and Ngara reset itself WARN WD Reset Slow Drive Found During a logging session the time it took for the drive to spin up was longe...

Страница 42: ...s and results information Carry out disk operation Calibrate logger Loggers running software version 5 00 and above must use host software version 2 1 and above 5 1 Installation of Host Software The R...

Страница 43: ...work configuration settings set on the Ngara see Section 4 4 3 If the Ngara can be accessed within a local network and is set to DHCP mode See Section 4 4 3 2 Ngara may also be accessed using the foll...

Страница 44: ...to Change current time weighting whilst in standby mode Enable maximum hold markers through the tick boxes provided Reset the maximum hold markers through the push button provided The display is updat...

Страница 45: ...f each configuration option is listed on Table 22 Figure 7 Main Logger Configuration Table 22 General Logger Configuration Item Description Idle Timeout Enable or Disable the unit idle timeout setting...

Страница 46: ...a triggering modes can be adjusted through the Trigger Parameters tab Triggering can be set as one of the following 1 At a predetermined SPL or Leq Level 2 Once a predetermined percentile reaches a re...

Страница 47: ...be reached for 5 seconds before triggering is asserted When trigger is set 30 seconds of internal buffered data is recorded The trigger is reset when the level falls below 60dB A for more than 5 secon...

Страница 48: ...nual Figure 10 Level trigger example 5 4 3 2 Setting an SPL or Leq Percentile Trigger Ngara can be set to continually monitor the current percentile levels over a given time period Version 25 7cd7566...

Страница 49: ...is calculated over a 5 minute period This period can only be set to a maximum of 5 minute blocks When trigger is set 30 seconds of internal buffered data is recorded This buffer can be set to a maximu...

Страница 50: ...User Manual Figure 12 Percentile Trigger Example 5 4 3 3 Setting an RMS Trigger For Engine Brake Analysis The following example illustrates to set an engine brake trigger Version 25 7cd7566 Page 50 o...

Страница 51: ...xample In this example Ngara will set a trigger event as soon as the RMS is greater than 3 12 It will then record 7 seconds of internal buffered data followed by 8 seconds of raw data after the trigge...

Страница 52: ...Ngara User Manual Figure 14 RMS Trigger Example 5 4 3 4 Setting a Time Based Trigger The following example illustrates how to set time based wave file recording Version 25 7cd7566 Page 52 of 80...

Страница 53: ...te Push Button Trigger The following example illustrates how to set a remote push button trigger wave file recording Figure 16 Push Button Trigger Example Ngara will trigger and record a wave file for...

Страница 54: ...rface would normally be off whilst logging to conserve battery but it would turn on daily at 4 00pm for one hour to allow for remote interrogation This feature is not available when operating in Indus...

Страница 55: ...interface is turned on 12V DC is also supplied to the 3G modem via the AUX output This setting is locked to Follow Ethernet Power when Logging to Noise Cloud 5 4 6 UDP Output Tab Ngara is capable of...

Страница 56: ...st be used with extreme care as very large time changes during a logging session may result in some loss of data ARL recommend using this setting only when Ngara is configured in a non logging configu...

Страница 57: ...oud Write Key This is the API access into the Noise Cloud server Frequency Weighting Frequency weighting of results to use Percentiles All LN that will be pushed to Noise Cloud 5 4 9 Email Tab Ngara e...

Страница 58: ...ields are not accessible 5 5 Logger Time Logger time can be updated by navigating to the following menu item File Logger Configuration Set Time Figure 22 Set Time Menu All settings are stored in inter...

Страница 59: ...set the current date time and timezone information to match that of the controlling PC 5 6 System Calibration Internal calibration factors can be updated by navigating to the following menu item File...

Страница 60: ...OK button is enabled 5 7 Logger Reboot For logger versions V 7 06 and later it is possible to remotely reboot the Ngara by navigating to the following menu item File Reboot Figure 26 Logger Reboot Ng...

Страница 61: ...following Start a logging session Stop a logging session Record reference levels Flush current internal buffers to disk 5 9 1 Starting Session The logger can be set to start a session by navigating t...

Страница 62: ...ollowing menu item Session Control Stop Figure 30 Stopping a Session Indication of the stop session command can be viewed through the logger s status information group described in Section 5 3 2 The i...

Страница 63: ...nce level at any stage of the logging session Ngara is capable of storing many reference levels throughout the course of a running session 5 9 4 Changing Disk Internal buffers can be flushed ready for...

Страница 64: ...wn in days Download session data Format current disk Perform statistical analysis on 100ms session date Re constitute Wave Files Re Format Ngara Drive 5 10 1 Detail Storage Media View A detailed view...

Страница 65: ...g the remote user interface as the downloading of raw audio files would create excessive network traffic This feature is not available when operating in Industrial Noise Monitor mode Figure 36 Statist...

Страница 66: ...ing a spare USB port on your PC 5 10 3 Remotely Formatting a USB Drive A USB device which is attached to Ngara may be formatted by navigating to the following menu item Disk Remote Format Figure 37 Re...

Страница 67: ...emoved from PCM files Disk Reconstitute Wave Files Figure 40 PCM Reconstitution The recorded 48kHz wave files are linear from the noise floor of the instrument to approximately 97dB 1kHz From 97dB to...

Страница 68: ...way to normalise samples to the required 1 0 levels when samples span multiple files whilst still maintaining calibration 5 10 6 Reformatting a USB Device Figure 41 USB Reformat A drive which has bee...

Страница 69: ...for adding an additional device to the network 6 1 Communication Ngara uses the port s shown on Table 24 for communication Table 24 Network Port Usage Port Description IN OUT 25 Email communication N...

Страница 70: ...d to use the Ngara AUX output connector This will ensure the modem can be powered off in the event that the battery voltage drops to critical levels When using this method of connectivity the suggeste...

Страница 71: ...table modem configuration files These will ensure all configuration requirements are met It is also a requirement that all remote 3G 4G Ngara systems be fully operation before they are provided to you...

Страница 72: ...l for all linearity tests 7 3 Environmental Reference Conditions Reference environmental conditions are given in Table 29 Table 29 Reference Environmental Conditions Description Value Air Temperature...

Страница 73: ...Hz Ideal dB Ngara dB Difference dB Tolerance dB 31 5 39 4 39 7 0 3 2 0 1 000 0 0 0 0 0 0 1 1 4 000 1 0 1 1 0 1 1 6 8 000 1 1 0 9 0 2 2 1 to 3 1 12 500 4 3 6 4 2 1 3 0 to 6 0 7 7 Microphone 7 7 1 Freq...

Страница 74: ...ertain microphone directional response at high frequencies Figure 43 shows the directional response for the UC 53A microphone Figure 43 UC 53A Directional Response 7 7 3 Thermal Characteristics The th...

Страница 75: ...ure 45 UC 53A Humidity Response 7 7 5 Reduction of Wind Noise by Windscreen During outdoor measurements wind noise can falsify measurement results To counter such problems the recom mended windscreen...

Страница 76: ...s Table 32 UC 53A Quick Specifications Description Value Model UC 53A Nominal Diameter inch Sensitivity 28dB 0dB 1V Pa Frequency Response 10 to 20 000 Hz Capacitance 12pF Diaphragm Type Titanium alloy...

Страница 77: ...Ngara User Manual Figure 47 10Hz to 1kHz Version 25 7cd7566 Page 77 of 80...

Страница 78: ...Ngara User Manual Figure 48 10Hz to 10kHz Version 25 7cd7566 Page 78 of 80...

Страница 79: ...Ngara User Manual Figure 49 1kHz to 10kHz Version 25 7cd7566 Page 79 of 80...

Страница 80: ...8 08 09 Juan Aguero Test build for Ethernet control issues v12 1 rc2 1 2018 08 17 Juan Aguero As released for testing noise cloud uploading v12 1 rc3 2018 08 20 Juan Aguero Cleanup modem messages and...

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