Flir Extech 407790A Analyzer User Manual PDF

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Summary of Content for Flir Extech 407790A Analyzer User Manual PDF

User Manual

Real Time Octave Band Analyzer 

Model 407790A 

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Table of Contents  1.  INTRODUCTION ................................................................................................ 3 

1.1 Instrument Care ............................................................................................ 4  1.2 Features ........................................................................................................ 5 

2.  DESCRIPTIONS ................................................................................................ 6  2.1 Meter Description .......................................................................................... 6  2.2 Operation Buttons ......................................................................................... 7  2.3 Display Screen .............................................................................................. 9  2.4 Analysis screen ........................................................................................... 11  2.5 Numeric Display screen .............................................................................. 12 

3.  MEASUREMENT PREPARATION AND SETUP ............................................ 13  3.1 Setting the Date and Time .......................................................................... 13  3.2 SD Memory Card ........................................................................................ 15  3.3 Setting the Backlight Auto Off time ............................................................. 15  3.4 Sub Channel Settings ................................................................................. 16  3.5 Selecting the Lmax/Lmin type .................................................................... 17  3.6 Comparator Output Operation .................................................................... 18  3.7 Trigger Mode Setup and Operation ............................................................ 21 

3.7.1 Trigger Setup ........................................................................................................... 22  3.7.2 External Trigger Setting .......................................................................................... 22  3.7.3 Trigger Time Setting ............................................................................................... 22  3.7.4 Trigger Level Setting ............................................................................................... 23 

4.MEASUREMENTS ............................................................................................. 25  4.1 Sound Level Measurements ....................................................................... 25  4.2 SEL, Leq, Lmax, Lmin, LN Measurements ................................................. 26  4.3 Sound Level and Octave Band Analysis Measurement ............................. 28  4.4 Sound Band - Leq, SEL, Lmax, Lmin and LN Analysis Measurement ....... 30 

5. STORING DATA TO MEMORY ........................................................................ 32  5.1 Manual Memory Storage ............................................................................ 32  5.2 Recalling Manually Stored Data ................................................................. 35  5.3 Erasing Manually Stored Data .................................................................... 37  5.4 Auto 1 Memory Storage .............................................................................. 38  5.5 Auto 2 Memory Storage .............................................................................. 41  5.6 Erasing Auto Stored Data ........................................................................... 42 

6. SOFTWARE DOWNLOAD AND INSTALLATION ........................................... 43  7. SOUND PRESSURE LEVEL - TECHNICAL NOTES ...................................... 44  8. CALIBRATION .................................................................................................. 45  9. SPECIFICATIONS ............................................................................................ 46  10. WARRANTY ................................................................................................... 49 

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1. Introduction 

Congratulations  on  your  purchase  of  the  Extech  407790A  Real  Time Octave  Band  Analyzer. This auto  ranging Type 2  integrating  sound  level meter  features 1/1 and  1/3  Octave  Band  realtime  noise  analyses.  The  407790A  offers  five  measurement  parameters: SPL (Sound Pressure Level), Leq (Equivalent Continuous Sound Pressure  Level), SEL (Sound Exposure Level), Lmax (Maximum Sound Pressure Level), and Lmin  (Minimum Sound Pressure Level). The builtin memory stores 12,280 data records in  sound  level mode and 1024 records  in Octave mode. The stored data can be easily  transferred  to a PC with  the 407790A  software and USB cable. This meter permits  choice of  A,  C, or Flat  Z weighting and Slow / Fast /impulse response  times. AC  and DC  analog output  signals  are  available  for  chart  recorders  and other  external  recording devices. Careful use of this device will provide years of reliable service. 

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1.1 Instrument Care 

Do not attempt to remove the mesh cover from the microphone as this will cause damage  and affect the accuracy of the instrument. 

Protect the instrument from impact. Do not drop it or subject it to rough handling.  Transport it in the supplied carrying case. 

Protect the  instrument from water, dust, extreme temperatures, high humidity and direct  sunlight during storage and use. 

Protect the instrument from air with high salt or sulfur content, gases and stored chemicals,  as this may damage the delicate microphone and sensitive electronics. 

Always switch the instrument off after use. Remove the batteries from the instrument if it  is not to be used for a long period of time. Do not leave exhausted batteries in the  instrument, as they may leak and cause damage. 

Clean the instrument only by wiping it with a soft, dry cloth or, when necessary, with a cloth  lightly moistened with water. Do not use solvents, abrasives, alcohol or cleaning agents 

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1.2 Features 

The Sound Level Meter complies with the requirements of IEC 616721:2003 standard for a   Class 2 instrument.  See specifications section for more applicable standards that apply to this  meter. 

1/1 octave band analysis from 31.5Hz to 8kHz 

1/3 octave band analysis from 25Hz to 10kHZ 

Can perform 1/1 and 1/3 octave band analysis simultaneously 

4GB Micro SD card 

USB interface 

Datalogging function 

AC/DC signal output available for level and graphic recorder 

Comparator output function 

External trigger input function 

Real time clock with calendar 

Main channel (sound meter, analyzer mode) 

 Sub Channel (sound level meter mode) 

The 407790A allows the following quantity measurements.  

Simultaneous measurements of all items with selected time weighting and frequency  characteristics. 

Sound level      Lp 

Equivalent continuous sound  Leg 

Sound exposure level    SEL 

Maximum sound level  Lmax 

Minimum sound level   Lmin 

Percentile sound level  LN (L05, L50, L90, L95) calculated from Lp 

Frequency rating    A, C, Z 

Time weighting  Main Channel    Fast, Slow, 10ms, impulse  Sub Channel    Fast, Slow, 10ms, impulse   

Safety Symbol:    Complies with EMC 

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2. Descriptions 

2.1 Meter Description 

Refer to the diagram below for the following descriptions. 

1. Windscreen  2. Microphone  3. Display  4. Operation keys  5. 6VDC adapter jack  6. DC analog output jack  7. AC analog output jack  8. Comparator output jack 

9. Trig IN jack  10. Micro SD card slot  11. Power switch  12. Hand strap  13. USB port  14. Battery compartment  15. Tripod mounting screw

FAST L

2k

[ 1 / 3 OCT ] 01 / 06 / 19 14:26:39

20

40

31.5Hz 500125

60

80

dB

100 A W

W8k L

65.2 dB

IEC 1260 CLASS2

O FF

O N

PO W

E R

C AL IEC LR14 1.5V X 4

ACCURACY : 1.5dB

O FF

O N

D C

AC

C O

N TR

A ST

O U

TP U

T D

C 6V

LI G

H T

SOUND ANALYZER

IEC 651 IEC 804 TYPE 2 1/1 & 1/3 OCTAVE BAND

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 2.2 Operation Buttons 

START/STOP  button 

Press to start or stop for recording the sound pressure measurement.   

PAUSE/CONT  button 

Press to temporarily pause (       ) a measurement) or resume () measurement. 

 M  button  Press to scroll through and select different processing modes. 

  LEVEL   

Press to select the level range for measurement. The following five settings are available.  20 to 90 dB, 20 to 100 dB, 20 to 110 dB, 30 to 120 dB, 40 to 130 dB. 

GRP/ NUM  button 

Press to switch between graph and numeric display for Octave measurements. 

SLM  1/1  1/3  button 

Press to switch to select the sound level meter display and analysis screen.  (SLM, 1/1, 1/3, 1/1&1/3) 

MENU 

  Press to enter menu screen to setup various menu parameters. Press again to close the  menu. 

 R  button 

Start or stop the auto Record process or press to manually store the measurement data  into  memory. 

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/     Press to move the octave frequency band marker during frequency analysis. 

+  /  -

     Press to select and set items in various menu screens. Holding the buttons down will cause  faster scrolling. 

FREQ WEIGHT TIME   button 

The FREQ WEIGHT selects the frequency weighting for the main channel. A weighting (A),  C weighting (C), and flat frequency response (Z).     The TIME WEIGHT selects the time weighting function for the main channel. (F, S, 10ms, I)  Fast: 125ms;  Slow: 1000ms;  10ms;  Impulse: 35ms 

Note: The frequency and time weighting for the sub channel can be selected by accessing  the menu screen. 

button (Backlight/Enter)  Backlight powers on the display backlight. Press the button again to turn backlight off.  When automatic Backlight Off function is selected from the menu screen, the backlight will  turn itself off automatically after the preset time.    Enter button will finalize a setting of an item in a menu or any other setting. 

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 2.3 Display Screen 

Mode of analysis

Measurement in progress symbol

USB link status

Trigger mode

Elapsed time

Memory

Store mode

Address

Level range

Overload indication

Sub channel level display

Sub channel Time weighting

Frequency weighting

Current time

Current dateComparator ON

Auto store full indication Manual store full indication

Power

status

Main channel level display

Time weighting

Main channel Frequency weighting

Underrange indication

Bar graph

1. Mode of analysis: Indicates the condition of the display screen. 

SLM: Sound level meter display 

1/1 OCT: Octave band analysis screen 

1/3 OCT: 1/3 Octave band analysis screen 

1/1 and 1/3 OCT: Simultaneous octave and 1/3 octave band analysis screen 

2. Measurement in progress: When a measurement recording is in progress or during auto store 

the  symbol flashes. During measurement pause the   symbol is displayed on the screen.  

3. USB Link Status: Shows if the USB is enabled or disabled. 

4. Trigger Mode: Controls the measurement and memory auto store start behavior. Available  modes are: Level 1 (LV1), Level 2 (LV2), EXT (EXT), and time (TIME). 

5. Elapsed Time: Displays the elapsed time in seconds during processing and storing memory. 

6. Memory: Displays the selected memory for storing data. 

FL: The data will be stored in the internal memory of the meter. 

Sd: The data will be stored on the micro SD card 

7. Store mode: Displays the selected mode for storing data in memory 

M: Manual store 

A: Auto store 

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8. Address: Displays current number of data surveys stored in memory. 

9. Bar graph: Displays the sound level as a bar graph. (The display is updated every 100ms) 

10. Level range: Displays the upper and lower limit of the bar graph. Can be changed with the 

 LEVEL  button. 

11. Underrange indication: When a signal is underrange the UN symbol will appear on the  screen. Use the  LEVEL  button to decrease the level range setting. If processed data is 

underrange the UN indication will remain on the screen until the next processing 

measurement is started. 

12. Overload indication: When a signal overload is detected, the screen will display OV for at  least 1 second. Use the  LEVEL  button to increase the level range setting. If processed 

data is over range the OV  indication will remain on the screen until the next processing 

measurement is started. 

13. Main channel frequency weighting: Indicates the main channel frequency characteristic. A:  Aweighting, C: Cweighting, Z: Zweighting (flat response) 

14. Main channel time weighting: Indicates the main channel time weighting characteristic.   F: Fast (125ms), S: Slow (1000ms), : (10ms), I: Impulse (35ms) 

15. Main channel level display: Displays the measured sound level in the main channel.   (The display is updated every second). 

16. Sub channel frequency weighting: Indicates the sub channel frequency weighting  characteristic. A: Aweighting, C: Cweighting, Z: Zweighting (Flat response).   The sub channel frequency weighting can be set from the menu screen. 

17. Sub channel time weighting: Indicates the sub channel time weighting characteristic.   F: Fast (125ms), S: Slow (1000ms), : (10ms), I: Impulse (35ms) 

18. Sub channel level display: Shows the measured sound level in the sub channel.   (The display is updated every second) 

19. Power status: When operating the meter on battery power the yellow segments will  decrease as the battery power drains. When the segment starts to flash, replace batteries. 

Yellow Yellow Yellow Yellow Red

  Battery good >   Replace       Segment flashes (critical) 

20.  Manual store full: When the manual stored memory is full, the MFul symbol is displayed. 

The manual data store capacity is 250 sets. 

21.  Auto store full: When the auto store memory is full, the AFul symbol is displayed. The auto 

store capacity is 250 blocks. 

22. Comparator ON: When the comparator function has been set to ON and a signal exceeds 

the comparator output jack, the indicator Cmp will appear on the display. A signal will 

output from the comparator output jack on the side panel (open collector). 

23. Current date: Displays the current date 

24. Current time: Displays the current time 

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 2.4 Analysis screen 

An example for the 1/1 & 1/3 OCT analysis screen is shown below. 

Use the  and   buttons to move the cursor to the target frequency band. 

1/1 and 1/3 analysis screen 

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 2.5 Numeric Display screen   

Example for 1/1 OCT, 1/3 OCT, and 1/1 & 1/3 OCT analysis screen are shown below. 

Use the  and   buttons to view a frequency that is not displayed. 

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3. Measurement Preparation and Setup  1. Battery installation: Remove the rear battery cover as shown below and insert (4) 1.5V C 

size alkaline batteries. Take care to observe battery polarity. Replace the battery cover. 

2. Battery replacement: When the battery voltage drops below operating voltage, 

battery symbol flashes on the display. 

3. AC adaptor connection: Insert the adaptor in the DC 6V jack on the side panel. When the AC  adapter is connected, the meter will be powered from the adapter even if batteries are  installed.  

Notes: 

To prevent the risk of damage, use only the factory supplied AC adapter. 

To prevent the risk of battery leakage, remove the batteries from the meter when the meter is  not in use. 

3.1 Setting the Date and Time 

Date and time information is stored with each record saved. Set the date and time as follows: 

1. Press power switch ON and wait until the measurement screen appears. 

2. Press the MENU button. The menu list screen will display. 

3. Press the +  /  -

  button to select D) Date setting (Y/M/D) and then press the enter   button. 

4. Press the +-

  button to set the value. Press button to confirm. 

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5. Continue pressing the above buttons to scroll through and set each option for date and time.  The meter will continue to scroll through setup for date Y/M/D and then the time settings  h/m/s. 

6. When the settings are correct, press the button to exit the setting mode. The clock will  start running with the new settings. 

7. Press MENU button to return to the measurement screen. 

Note: The clock has an error of about 1 minute per month. Before taking measurement, be sure  to check and set the time if required. 

Date 

Time 

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3.2 SD Memory Card 

Measurement data can be stored on a removable SD memory card for later use.   Note: Power OFF the meter before inserting or removing the memory card.     Use only a 4GB micro SD card. Removing SD card or powering the meter off while data is storing  to the card can cause internal data to be destroyed. 

1. Insert the card taking care to observe the correct orientation. Push the card in carefully,  until it is properly sealed. 

2. To remove, push the card. The SD card with pop out and can be removed. 

3.3 Setting the Backlight Auto Off time 

1. Press the     to turn the backlight on or off. 

2. Press the MENU key to bring up the menu list screen. 

3. Use the +  /  -

 key to select Backlight Auto Off then press the key. 

4. Use the +  /  -

 key to select the automatic turn off time then press the key.  Options  are: 30 seconds, 1 minute, 3 minutes or OFF (without automatic turn  off function). 

5. Press MENU key to return to the measurement screen. 

To turn the backlight off before the automatic turn  off time, press the   key. 

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3.4 Sub Channel Settings 

To access the sub menu setting press the following buttons. 

1. Press the MENU button to enter the menu list screen. 

2. Use the +  /  -

 buttons to select G). Sub Time Weight then press button. 

3. Use the +  /  -

 button to select the desired time weighting  

F, S,  (10ms) or I (Impulse 35ms), then press button. 

4. Press the +  /  -

 buttons to select H). Sub Freq Weight then press button. 

5. Press the +  /  -

 buttons to select the desired frequency weighting A, C or Z, then press  button. 

6. Press MENU button to return to the measurement screen. 

Note: There is no frequency analysis function for the sub channel. Only the all  pass value is  measured. 

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3.5 Selecting the Lmax/Lmin type 

Band   (Band maximum/band minimum): 

The analysis result applies to the point where the level for each frequency band was maximum  or minimum within the sampling period. 

AP   (Allpass maximum/allpass minimum): 

The analysis result applies to the sub channel allpass and bandpass level values taken at the  point where the allpass level in the main channel was maximum/minimum within the  sampling period. 

AP (S)   (Allpass maximum/allpass minimum): 

The analysis result applies to the bandpass level values (excluding the sub channel allpass  levels) taken at the point where the allpass level in the main channel was  maximum/minimum within the sampling period. The sub channel allpass level is taken at  the maximum/minimum point within the sampling period, independently of the main  channel level.

1. Press the MENU button to enter the menu list screen. 

2. Use the +  /  -

 buttons to select I). Lmax/Lmin Type then press button. 

3. Use the  +  / 

-  buttons to select the desired Band, AP or AP (S) type then press button. 

4. Press MENU button to return to the measurement screen. 

This setting is effective in SLM mode and Octave band analyzer mode. 

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3.6 Comparator Output Operation 

The comparator output is an open collector output that can be used to control external  equipment. 

1. Press the MENU button to enter the menu list screen. 

2. Use the +  /  -

 buttons to select J). Comparator then press button to display the  ON/OFF setting. 

3. Press the +  /  -

 buttons to select ON then press button. 

4. Press the + /   -

 buttons again to select 1). Comparator Level. Set the desired level 

then press button. (Setting range 25 to 130dB, 1  dB steps) 

5. Follow the above steps to select 2). Comparator Band. Set the band to desired level then 

press button. (MAIN AP/31.5Hz/63Hz/8kHz or 1/3 octave bands). 

6. Press the MENU button to return to the measurement screen. 

AP

AP

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AP

AP

AP

AP

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Comparator output:  

In the SLM mode, only the AP is selected as comparator band.  

In the 1/1 OCT mode, only the AP or 1/1 octave band is selected as comparator band. 

Comparator output: Open collector output; bandlevel determination;              Max. applied voltage:  24VDC; Max. drive current: 50mADC 

1

2

3

1. Comparator signal output continues for 0.5 seconds after the signal crosses the threshold level

2. Comparator Level 

3. Time 

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3.7 Trigger Mode Setup and Operation 

A measurement can be initiated by one of three triggers: time trigger (timecontrolled  triggering), level trigger (sound level controlled triggering), and external trigger (triggering by an  external signal).   

Level trigger 1: Measurement starts when the trigger level is exceeded and ends after the  measurement time. 

The trigger level is valid at any time. 

Setting items: 

Trigger Slope Type: +,  

Trigger Level: 25 to 130dB, 1dB steps. 

Trigger Band: MAIN AP/31.5Hz/63Hz/125Hz.8kHz (1/3 octave bands)   

Level trigger 2: Single measurement is made when trigger level is exceeded. 

The trigger level is valid at any time. 

Setting items: 

Trigger Level: 25 to 130dB, 1dB steps. 

Trigger Band: MAIN AP/31.5Hz/63Hz/125Hz8kHz (1/3 octave bands).   

Time trigger: This is a reoccurring trigger timer that starts a measurement after a trigger timer.  

The measurement ends after the measurement time.  

The trigger timer is valid at all times. 

Setting items:   

Trigger Time: h:m:s   

External trigger: A Measurement starts at falling edge of a logiclevel (0 to 5V logic) signal at the  external trigger input. A Pulse width of 1ms or more is required. 

The external trigger is valid at all times.

Trigger Operation  example 

1. Sound Level 

2. Time 

3. Slope    + Trigger 

4. Slope      Trigger 

5. Trigger Level 

1

2

3 4

5

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3.7.1 Trigger Setup 

1. Chose trigger operation [off, Level 1, Level 2, External, or Time].

2. Set the Trigger Band: AP or Octave band frequency

3. For Level 1 and 2: chose the Trigger level in dB.

4. External Trigger, chose slope (+ or )

AP

3.7.2 External Trigger Setting 

1. Press the MENU button to enter the menu list screen.

2. Use the + / -

buttons to select K). Trigger then press the button.

3. Use the + / -

buttons to select EXT then press the button.

4. Press the MENU button to return to the measurement screen.

3.7.3 Trigger Time Setting 

This is a reoccurring Triger that will start a meter recording at a specific Trigger delay time setting and the recording will stop at the set Measurement time and then start up again at the trigger wait time.

1. Press the MENU button to enter the menu list screen.

2. Use the + / -

buttons to select K). Trigger then press the button.

3. Use the + / -

buttons to select TIME then press the button.

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4. Use the + / -

buttons to select 2). Trigger Band then press the button.

5. Use the + / -

and buttons to set the value to AP then press the button.

6. Use the + / -

buttons to select 3). Trigger Time then press the button.

7. Use the + / -

and buttons to set the value of the reoccurring trigger timer

Hour:Minute:Second then press the button.

8. Press the MENU button to return to the measurement screen.

AP

AP

3.7.4 Trigger Level Setting 

The Triger can be set to start a meter recording at a specific Trigger dB level setting.

1. Press the MENU button to enter the menu list screen.

2. Use the + / -

buttons to select K). Trigger then press the button.

3. Use the + / -

button to select the desired option LEVEL1 or LEVEL2 then press the button.

4. Use the + / -

buttons to select 1). Trigger LEVEL then press the key.

5. Use the + / -

buttons to set the desired trigger level value (25 to 130). Then press the button.

6. Use the + / -

buttons to select 2). Trigger Band then press the button.

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7. Use the + / -

buttons to select the desired trigger band then press the button.

8. Use the + / -

buttons to select 4). Slope Type then press the button.

9. Use the + / -

buttons to select the desired trigger slope + or Slope. Then press the button.

Note: For LEVEL 2 trigger, ignore the slope setting and only use the Slope+ trigger.

10. Press the MENU button to return to the measurement screen.

11. Press the R button on the meter to start automatic recording. The meter will start recording when the trigger level is exceeded.

AP

AP

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4.Measurements 

All processing functions provided by the meter (Leq, SEL, Lmax, Lmin, Ln) are carried out simultaneously. For example, when equivalent continuous sound level measurement is selected, the sound exposure level and percentile level are also determined.

4.1 Sound Level Measurements 

1. Press the power button to power on the meter. After the poweron screen displays the SLM measurement screen will appear.

The measurement parameter settings that were active before the meter was turned off will be saved.

2. Use the FREQ WEIGHT TIME button to select the Main Channel frequency weighting

characteristic. For normal sound level measurements, select the A setting.

3. Use the FREQ WEIGHT TIME button to select the Main Channel time weighting characteristic.

For normal sound level measurements, select the F (Fast) setting.

4. Use the LEVEL buttons to set the dB level range. Choose a setting in the middle of the display range of the main channel bar graph indicator.

If the OV or UN indicators appear, change the level range setting.

5. The Main channel and Sub channel level indicators display the currently measured sound pressure levels. The reading is updated once every second.

6. The PAUSE/CONT button can be used to stop and resume the updating of the level indication.

In sound level meter mode, the bar graph indication will stop during pause.

In the pause condition, a pause symbol ( ) appears on the display.

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4.2 SEL, Leq, Lmax, Lmin, LN Measurements 

1. Power on the meter. After the poweron screen displays, the SLM measurement screen appears.

2. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For

normal sound level measurements, select the A setting.

When C (CWeighting) is selected, the equivalent continuous sound pressure level (LCeq) is measured.

3. Use the FREQ WEIGHT TIME button to select the time weighting characteristic. For normal

sound level measurements, select the F (Fast) setting.

(This setting does not affect a measurement result of continuous sound level mode.)

Note: The meter performs highspeed sampling of the sound pressure waveform to determine Leq and SEL. It is not affected by the time weighting characteristics.

4. Use the LEVEL buttons to set the level range. The main channel bar graph indicator should be in the middle of the range.

If the OV or UN indicators appear, change the level range setting.

5. Set the measurement time from the menu. Press the MENU button to enter the menu list

screen.

6. Use the + / -

buttons to select A). Measurement Time then press button.

7. Use the + / -

and buttons to set the desired measurement time from 1s to 23h 59m 59s.

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8. Press the button to exit the measurement time setting.

9. Press MENU button to return to the measurement screen.

10. Press the START/STOP button to start the measurement. Previously measured values will be

cleared. While the measurement is in progress, the symbol will flash and the elapsed time will display on the screen. When the measurement time has elapsed, the measurement is terminated automatically.

To terminate the measurement before the allocated time, press the START/STOP button.

If signal overload or an underrange occurs at least once during the measurement, the OV or

UN symbols will appear on the screen. This will indicate that overload or underrange

data are comprised in the processed values.

During measurement, the PAUSE/CONT key can be used to paused and resume the

measurement. During pause, the pause ( ) symbol is shown. (The paused interval is not included in the measurement time.)

Important: During measurement, the LEVEL button, FREQ WEIGHT TIMEbutton, TIME

WEIGHT and SLM/RTA function are disabled. Be sure to complete all settings before starting the measurement.

11. When the measurement is completed, the symbol will disappear.

The main channel and sub channel measured values of the Leq, SEL (LE), Lmax, Lmin, L05, L10, L50, L90 and L95 are displayed.

If the indicator OV is shown, the processed data includes data where the sound level signal

caused an overload condition.

If the indication UN is shown, the processed data includes data where the sound level signal

caused an underrange condition.

The bar graph only shows the sound level value.

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4.3 Sound Level and Octave Band Analysis Measurement 

1. With the power ON wait until the SLM measurement screen appears on the display.

2. Use the SLM 1/1 1/3 button to select the desired 1/1 OCT, 1/3 OCT or 1/1 & 1/3 OCT band or SLM

measurement screen.

3. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For normal

sound level measurements, select the A setting.

4. Use the FREQ WEIGHT TIME button to select the time weighting characteristic. For normal sound

level measurements, select the F (Fast) setting.

5. Use the LEVEL buttons to set the level range.

Select a setting in which the main channel allpass value indicator is in the middle of the range.

If the OV or UN indicators appear, change the level range setting.

6. The level indicator displays the currently measured Sound band level.

Use the GRP/NUM button to toggle the measurement screen between graph and numeric display.

If the graph display is selected, use the and buttons to move the cursor to the desired

frequency band.

In the 1/1 & 1/3 OCT numeric display, frequencies that are currently not displayed can be called up with the and buttons.

To stop or resume updating the band level indication press the PAUSE/CONT button. When

pause is selected, a pause symbol ( ) appears on the display.

Important: During sound band measurement, do not press the MODE key or other parameter

symbols will be displayed.

The sound band level is being displayed when there is no character string after the basic indicator.

LAF: Sound band level is being displayed.

LAeq: Sound band level is not being displayed.

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4.4 Sound Band  Leq, SEL, Lmax, Lmin and LN Analysis Measurement 

1. Power on the meter and wait until the SLM measurement screen appears.

2. Use the SLM 1/1 1/3 button to select the desired 1/1 OCT, 1/3 OCT or 1/1 & 1/3 OCT band or SLM

measurement screen.

3. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For

normal measurements, select the A setting.

4. Use the FREQ WEIGHT TIME button to select the time weighting characteristic. For normal

measurements, select the F (Fast) setting.

5. Use the LEVEL buttons to set the level range. Select a setting in which the main channel allpass value indicator is in the middle of the range.

If the OV or UN indicators appear, change the level range setting.

6. Set the measurement time from within the menu. Press the MENU key to bring up the menu

list screen.

7. Use the + / -

buttons to select A). Measurement Time then press the key.

8. Use the + / -

and buttons to select the desired measurement time from 1s to 23h 59m 59s.

9. Press the key to exit the measurement time setting.

10. Press MENU key to return to the measurement screen.

11. Press the START/STOP key to start the measurement. The previous measurement values will be cleared.

While the measurement is in progress, the symbol flashes and the elapsed time is displayed. When the measurement time has elapsed, the measurement is terminated automatically.

To terminate the measurement before the allocated time, press the START/STOP key.

If the indicator OV is shown, the processed data includes data where the sound level signal

caused an overload condition.

If the indication UN is shown, the processed data includes data where the sound level signal

caused an underrange condition.

During measurement, the PAUSE/CONT key can be used to pause and resume the measurement.

During pause, the pause ( ) symbol is shown. (The paused interval is not included in the measurement time.)

Important 

During measurement, the LEVEL button, FREQ WEIGHT TIME button, TIME WEIGHT and

SLM/RTA functions are disabled. Be sure to complete all settings before starting the measurement.

12. When the measurement is completed, the symbol disappears.

If OV is displayed, the processed data includes data where the sound level signal caused an overload condition.

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If the indication UN is shown, the processed data include data where the sound level signal caused an underrange condition.

13. Press the M button to cycle through the Lp Leq LE (SEL) Lmax LminL05L10L50L90L95 measured value on the screen.

Pressing the GRP/NUM button switches the measurement screen between graph and numeric

display.

In graph display, use the and buttons to move the cursor to the desired frequency band.

In the 1/1 & 1/3 OCT numeric display, frequencies that are not displayed can be called up with the and buttons.

The PAUSE/CONT button can be used to stop and resume the updating of band level indication. In

the pause condition, a pause symbol ( ) appears on the display. (The pause interval is not included in the measurement time.)

During measurement, you can use the MODE key to check the measured values as currently

calculated.

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5. Storing Data to Memory  The meter can store measurement data in the internal memory or on a micro SD card. There are three

different ways of storing data, as listed below.

Manual: 

In this mode, the operator stores the measured sound level data and processed value data into the memory manually.

Press the R record button to cause the current sound level and processed values derived from

the measurement, as well as the measurement parameters and time of recording to be recorded in a single measurement.

Memory capacity: max. 250 data sets

Manually stored data can be recalled by the meter.

Auto 1: 

Sound level meter mode 

Continuous store of main channel and sub channel allpass values as 1 set, at preset record interval times.

Octave Analyzer mode 

Continuous store of main channel sound level Lp values for each band and allpass values, sub channel allpass values as 1 set at preset record interval time.

Auto 2: 

Sound level meter mode 

Continuous store of main channel and sub channel allpass values as 1 set at preset measurement integrate time.

Octave Analyzer mode 

Continuous store of main channel sound level Lp values for each band and allpass values, sub channel allpass values as 1 set at preset measurement integrate time.

Automatically recorded data can be retrieved using the supplied software.

5.1 Manual Memory Storage 

Memory Store: 

Press the store key to store the current sound level and processing values. Only the sound level is stored when the R button is pressed. There will be no processing values displayed when the meter is powered on.

1. Power on the meter.

2. Press the MENU button to enter the menu list screen.

3. Use the + / -

buttons to select B). Storage then press the key.

4. Use the + / -

buttons to select FLASH or SD Card then press the key.

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Selecting FLASH will store the data in the internal memory.

Selecting SD Card will store the data on the SD CARD.

5. Use the + / -

buttons to select C). Store Mode then press the key.

6. Use the + / -

buttons to select MANUAL then press the key.

7. Press the MENU button to return to the measurement screen.

8. Press the R button. The sound level will be recorded. If processing was being carried out, the

processed values at the point where the R key is pressed will also be recorded.

The store process takes about 1 second. When it is completed, the address is incremented by

one step, which allows you to record multiple data simply by pressing the R key repeatedly.

Note: When address 250 is reached, the MFul symbol will be displayed and no more data can be

stored.

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5.2 Recalling Manually Stored Data 

1. Power on the meter.

2. Press the MENU button to enter the menu list screen.

3. Use the + / -

buttons to select M). Recall then press the button.

4. Use the + / -

buttons to select the store address whose data you want to recall, then

press the button. The data stored in memory will display.

5. In analyzer mode, the GRP/NUM key can be used to switch between numeric display and

graph display.

6. Press the button and + / -

or / buttons to select a different store address whose data you want to recall.

7. Press the MENU button two times to exit this mode.

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5.3 Erasing Manually Stored Data 

1. Press the MENU button to enter the menu list screen.

2. Use the + / -

buttons to select L). Clear Record then press the button.

3. Use the + / -

buttons to select MANUAL then press the button.

A confirmation message will appear. To erase the data, press the button. To cancel the process,

press the MENU button.

Note: you can also erase the manual memory from the software.

AP

AP

AP

AP

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5.4 Auto 1 Memory Storage 

Memory Store 

Continuously store the current measured data as 1 set, at preset record interval times.

1. Power on the meter.

2. Press the MENU button to enter the menu list screen.

3. Use the + / -

buttons to select B). Storage then press the button.

4. Use the + / -

buttons to select FLASH or SD Card then press the button.

Selecting FLASH will store the data in the internal memory.

Selecting SD Card will store the data on the SD CARD.

5. Use the + / -

buttons to select C). Store Mode then press the button.

6. Use the + / -

buttons to select AUTO 1 then press the button.

7. Use the + / -

buttons to select Interval Time then press the button.

8. Use the + / -

buttons and the button to set the desired record interval time from 1

second to 23h59m59s, then press the button.

9. Use the + / -

buttons to select A). Measurement time then press the button.

10. Use the + / -

and button to set the desired measurement time from 1 second to

23h59m59s, then press the button.

Note: Measurement Time must be greater than or equal to the set Interval Time

11. Set the other measurement parameters (trigger mode, sub channel etc.) as required, using

the MENU button to select setting items.

12. Press the MENU button to return to the measurement screen.

13. Press the STORE button to start the measurement. If a trigger has been set, measurement

will start when the trigger conditions are met.

Important: During recording, only the START/STOP , PAUSE/CONT , , STORE , and M

buttons are operative. Other keys such as the FREQ WEIGHT TIME and LEVEL button

have no effect. Be sure to complete all settings before starting the store process.

If the trigger mode is OFF, storing of measurement data will stop when the end of the measurement time is reached.

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To stop the process earlier, press the START/STOP or the R key.

When the store is completed or stopped, the memory block address is incremented by one step.

Note: When memory block address 250 is reached, the AFul symbol is displayed and no more

data can be stored.

The AUTO recording of data can only be read by PC, it cannot be recalled by the meter.

1 2

3

4

5

1. Measurement time (duration of test)

2. Measurement time (duration of test)

3. Measurement Stop or Memory full is reached (AFu)

4. Interval time (sample time)

5. Trigger time or Trigger event

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5.5 Auto 2 Memory Storage 

Memory Store 

Continuously store the processed data at a preset measurement integrated time.

1. Power on the meter.

2. Press the MENU button to enter the menu list screen.

3. Use the + / -

buttons to select B). Storage then press the button.

4. Use the + / -

buttons to select FLASH or SD Card then press the button.

Selecting FLASH will store the data in the internal memory.

Selecting SD Card will store the data on the SD CARD.

5. Use the + / -

buttons to select C*). Store Mode then press the button.

6. Use the + / -

buttons to select Auto 2 then press the button.

7. Use the + / -

buttons to select Integrate Time then press the button.

8. Press the + / - and the buttons to set the desired measurement integrated time from 1 second to 23h59m59s, then press the key.

9. Use the + / -

buttons to select A). Measurement time then press the button.

10. Use the + / -

and buttons to set the desired measurement time from 1 second to

23h59m59s, then press the button.

Note: Measurement Time must be greater than or equal to the set Interval Time

11. Set the other measurement parameters (trigger mode, sub channel etc.) as required, using

the MENU button to select settings.

12. Press the MENU button to return to the measurement screen.

13. Press the R button to start the measurement. If a trigger has been set, measurement will

start when the trigger conditions are met.

The AUTO recording of data can only be read using the PC software. It cannot be recalled by the meter.

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5.6 Erasing Auto Stored Data 

1. Press the MENU button to enter the menu list screen.

2. Use the + / -

buttons to select L). Clear Record then press the button.

3. Use the + / -

buttons to select Auto then press the button.

A confirmation message appears. To erase the data, press the button. To cancel the process,

press the MENU button.

Note: you can also erase the manual memory from the software.

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6. Software Download and Installation 

The 407790A software is available for free download from the WWW.EXTECH.COM web page, located under the Software downloads section.

SAVE the 407790A software to your PC.

Perform an Extract All to unZIP the files.

Run ExtechInstaller.exe to install the software.

There is no USB driver, as the meter attaches as a Human Interface device.

The software has a Help manual available to understand the full operation.

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7. Sound Pressure Level  Technical notes 

1. The decibel (dB)

The range over which the human ear responds to sound pressure (noise) is extremely large; in

Pascals (Pa) it is 20Pa (the threshold of hearing) to 100 Pa (the threshold of pain). The measurement of sound pressure has been made more convenient by the use of the decibel, which is logarithmic. However, decibels are nonlinear and therefore cannot be added together. A simple rule is that doubling the amplitude of the noise under test causes the level to rise by 3dB.

2. SLMsound level meter: Instantaneous sound pressure level (SPL) is used for spot checks to establish instantaneous noise levels. SPL is defined by the logarithmic equation:

SPL (in dB): 20 log10

0P

P

Where P = rms measured sound pressure level

P0 = rms reference sound pressure level (20 Pa)

3. Leqlevel equivalent (continuous): Leq is used to assess the rms average noise level over a preset period of time, often the starting point of a noise assessment. To take a Leq measurement the period of time over which it is to be made must be selected. The longer the period of measurement time, the more accurate the Leq reading will be, a typical period is 8 hours (the length of a working day).

4. SEL Sound exposure level (LE)

SEL measurements are almost identical to Leq measurements but normalized or compressed to 1 second. This allows the total sound energy of an event, such as train passing a platform, to be evaluated. Another event, such as the next train, which lasts for a different amount of time, can be measured in the same way. The two readings can be compared to assess how much total noise the passengers standing at the platform were exposed to by each train.

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8. Calibration 

Calibrating the 407790A requires an acoustical calibrator such as the Extech Model 407766 or 407744 that can provide 94.0dB or 114dB at 1kHz.

1. Set the power switch to the OFF position.

2. Press and hold the + and -

buttons then turn the power ON until CAL appears on the screen.

3. Insert the microphone into the opening of the acoustical calibrator.

4. Switch the calibrator ON (1kHZ 94dB or 114dB)

5. Use the + and -

buttons to adjust the reading of the meter to match the sound calibrators output value. (adjust range from 12.8 to 12.7dB).

6. Press the button to store the calibrated value.

7. Switch the calibrator and sound meter OFF.

8. Remove the calibrator from the microphone very slowly to avoid damaging the microphone.

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9. Specifications 

Applicable Standards: IEC 616721: 2013 Class 2, IEC 612601: 2014 Class 2, ANSI S1.11: 2004 Class 2, ANSI S1.4: 1983 Type 2, ANSI S1.43: 1997 Type 2

Measurement functions: Simultaneous measurement of main channel and sub channel. Frequency weighting and time weighting are set independently for main and sub channel.

Sound level meter mode: Allpass processing for the measurement items listed below is carried out separately for the main channel and sub channel

Analyzer mode: For the main channel, octave, octave 1/3 or simultaneous octave, 1/3 octave band realtime processing and allpass processing are carried out.

o For the sub channel, only allpass processing is carried out.

Processing types in each operation mode 

Channel  Main  Sub 

Sound  level meter  mode 

AP/OCT AP AP

Frequency weighting

A/C/Z A/C/Z

Time weighting F/S/10ms/I F/S/10ms/I

Measurement values

Lp, Leq, SEL, Lmax, Lmin, LN Lp, Leq, SEL, Lmax, Lmin, LN

Analyzer  mode 

AP/OCT AP, OCT AP

Frequency weighting

A/C/Z A/C/Z

Time weighting F/S/10ms/I F/S/10ms/I

Measurement values

Lp, Leq, SEL, Lmax, Lmin, LN Lp, Leq, SEL, Lmax, Lmin, LN

Measurement time: 1 to 59 seconds, 1 to 59 minutes, 1 to 24 hours

Microphone: inch electret condenser type

Display: Backlit color TFT LCD (320240 dot matrix)

Update frequency: 100ms

Accuracy: 1.0dB (ref 94dB @1kHz)

Measurement Frequency range: Octave analysis 31.5 Hz to 8 kHz; 1/3 Octave analysis 25 Hz to 10kHz

Frequency weighting: A, C, Z

Inherent noise: Aweighting max. 17dB; Cweighting max. 25dB; zweighting max. 30dB

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Time weighting: 

Main channel: Fast (125ms), Slow (1000ms), 10ms, Impulse (35ms)

Sub channel: Fast (125ms), Slow (1000ms), 10ms, Impulse (35ms)

Measurement level range:  

Aweighting: 25 to 130dB

Cweighting: 33 to 130dB

Zweighting: 38 to 130dB

Total meter range: 25dB to 130dB (Aweighting, 1kHz)

Linear operating range: 90dB

Level Range: 20 to 90dB, 20 to 100dB, 20 to 110dB, 30 to 120dB, 40 to 130dB

Sampling cycle: 20.8 S (LN: 100ms)

Trigger function: Controls measurement and memory store start

Level 1: Trigger level (1dB steps) serves as threshold for starting measurement

Level 2: Single measurement is carried out when trigger level is exceeded

EXT: External trigger connector for logiclevel signal with falling edge detection

TIME: Trigger event recurrence interval (trigger time) is set.

Store: Sound level values and processing results are stored in manual store or auto store mode.

Data can be stored in internal memory or on micro SD card.

Manual store: Data for measurement results and measurement start time are stored manually, in single address increments.

Data store capacity: max. 250 data sets.

Auto store: Measurement results are stored continuously at the preset record interval time (for Auto 1) or the preset measurement integrated time (for Auto 2), and the measurement time.

Data store capacity: Memory capacity can be divided to 250 blocks max.

Memory capacity: See Table below (Manual/Auto storage blocks are separate)

Storage type

Mode  Flash  SD card 

Sound level meter 25087 data sets 29992366 data sets

1/1octave analysis 16185 data sets 19944162 data sets

1/3octave analysis 9466 data sets 11942248 data sets

1/1 and 1/3 OCT mode 7839 data sets 9946834 data sets

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Data recall: Allows viewing of the manually stored data.

AC output: 1 Vrms at FS (full scale); Output impedance approx. 5k; Load impedance 100k

DC output: 10mV/dB; Output impedance approx. 5k; Load impedance 100k

External trigger input: Detection of 0 to 5V logic level signal, falling edge trigger, pulse width 1ms or more

USB: Allows connection to a computer as storage device, or use a communication device for unit control via communication commands.

Power: Four (4) C size 1.5V alkaline batteries

Battery Life: Approx. 2 hours

External DC power supply: 6 VDC, 1A

Operating Temperature/Humidity: 14 to 122oF (10 to 50 ); 10 to 90%RH

Storage Temperature/Humidity: 14 to 140oF (10 to 60 ); 10 to 75%RH

Environment conditions: Altitude up to 2000 meters

Dimensions & Weight: 13.6 (H) x 4.0 (W) x 2.4 (D) (34.5 10 6cm); Approx.33.5 oz. (950g) including batteries

Accessories: Four (4) C 1.5V batteries, hardshell carrying case, CDROM, USB cable, 4GB micro SD card, Windscreen, 3.5mm plug, and AC adaptor

Optional accessories: Microphone extension cable (4.7m (15ft), p/n 407764EXT), Sound level calibrator, Tripod

407790A-en-US_v2.0 8/16 49

10. Warranty  FLIR Systems, Inc. warrants this Extech Instruments brand device to be free of defects in parts and workmanship for one 

year from date of shipment (a six month limited warranty applies to sensors and cables). If it should become necessary  to return the instrument for service during or beyond the warranty period, contact the Customer Service Department  for authorization. Visit the website www.extech.com for contact information. A Return Authorization (RA) number  must be issued before any product is returned. The sender is responsible for shipping charges, freight, insurance and  proper packaging to prevent damage in transit. This warranty does not apply to defects resulting from action of the  user such as misuse, improper wiring, operation outside of specification, improper maintenance or repair, or  unauthorized modification. FLIR Systems, Inc. specifically disclaims any implied warranties or merchantability or fitness  for a specific purpose and will not be liable for any direct, indirect, incidental or consequential damages. FLIRs total  liability is limited to repair or replacement of the product. The warranty set forth above is inclusive and no other  warranty, whether written or oral, is expressed or implied. 

Calibration, Repair, and Customer Care Services  FLIR Systems, Inc. offers repair and calibration services for the Extech Instruments products we

sell. We offer NIST traceable calibration for most of our products. Contact our Customer Service Department for information on calibration service availability. Annual calibrations should be performed to verify meter performance and accuracy. Technical support and general customer service is also provided, refer to the contact information provided below.

Copyright  2016 FLIR Systems, Inc.  All rights reserved including the right of reproduction in whole or in part in any form

www.extech.com

Support Lines: U.S. (877) 2398324; International: +1 (603) 3247800 

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