Sound level meter - Frequently Asked Questions

Using our standard sound level meter LA-1240, we measure the equivalent sound level (L _Aeq) over a 10-minute period, as well as the maximum value (L _Amax) and time-weighted sound levels (L ₅, L ₁₀, L ₅₀, L ₉₀, L ₉₅) of the ambient noise. The measured values are automatically saved to the sound level meter's memory and then transferred to a PC for processing and management using spreadsheet software (Excel).

◎ For details such as measurement points, please refer to our separate document, "Q&A Collection for Workplace Environment Measurement."

1. Start the sound level meter.

• Turn on the power while holding down the <CAL> key.
• Use the <△><▽> buttons to select the measurement condition "COND 4".
• Confirm with <START>. Turning on <KEYPROTECT> on the bottom will prevent you from changing the measurement conditions. For information on checking, changing, and registering the measurement conditions, please refer to item 6.

Contents of COND 4 at the time of shipment


Frequency Correction Characteristics	A
Dynamic characteristics	FAST
Level range	40～110dB
Measurement (actual measurement) time	10 minutes
Measurement period	0 minutes
Total measurement time	0 hours
Measurement start time	――：――

2. Check the operation of the sound level meter.

• Check the battery level.

  



• Press <CAL> and confirm that "CAL" is displayed in the lower right corner of the screen.
• Verify that the noise level display shows "104.0 dB" ± 1 dB.
  For details, please refer to the instruction manual, "calibration of the Sound Level Meter."

  

• Check the clock. If it's not correct, press and hold the <L _p L _eq... (DATE)> button while turning on the power to set it.
• Use ＜△＞＜▽＞ to make changes, ＜FASTSLOW＞ to shift digits, and ＜START＞ to confirm.

  

3. Start of measurement

• Pressing <START> will begin the measurement and display the screen as shown below.
• It will automatically stop after 10 minutes.

  

• The measurement results are saved to memory. Each time you press <STORE>, the data is saved starting from the smallest address. You can also specify an address. Up to 300 data points can be saved. For details, please refer to the instruction manual.

4. Data Transfer

• Connect the computer and the sound level meter with a cable.
• Turn on the sound level meter.
• Start the "memory transfer" sample program.
• The RS-232C communication conditions setting screen will appear, so set the conditions and press <OK>.

  

• Select "MANUAL" under "Memory Mode".
• Specify the save location and file name.

  

• Pressing <OK> will start the transfer.
• Once the transfer is complete, press and hold the <PRINT (MM CLEAR)> button while turning on the power to clear the manual memory (MM) and prepare for the next measurement.

5. Processing in Excel spreadsheet

• Start Excel.
• Click "File" → "Open" in the menu.
• Change the file type in the bottom left to "All Files (*.*)".
• Select the "****.txt" file you saved in step 4 and click "Open".
• Select the data format "Commas, tabs, etc..." and click "Next".
• Select "comma" as the column delimiter and click "Next".
• Select "General" as the data format for the column and click "Finish".
• A text file (***.txt) is imported into Excel.
• Save this file. Click "File" → "Save As" in the menu to save it.

6. Confirmation, modification, and registration of measurement conditions.

You can set the sound level meter's measurement conditions from your computer. The measurement conditions can be saved to the sound level meter's designated panel conditions (COND 1-9). <Operation>
• Connect the computer and the sound level meter with a cable.
• Turn on the sound level meter.
• Start the "memory transfer" sample program.
• The RS-232C communication conditions setting screen will appear, so set the conditions and press <OK>.
• Select "Condition Number" on the left, configure the settings, and press <Write> to write the measurement conditions to the sound level meter.
  Please refer to the next section for details on the settings.

  

  Example of the "COND 4" setting at the time of shipment

Menu commands and settings

○ Menu bar

＜END＞	End of sample program for setting condition memory
＜COM＞
┣━━━	＜OPEN＞	Open the port
┣━━━	＜CLOSE＞	Close the port.
┗━━━	＜Condition＞	Return to the communication settings screen.


○Setting items

<Frequency Weighting> (Frequency weighting characteristics)	Setting the frequency correction characteristics
<Time Waiting> (Dynamic characteristics)	Setting Dynamic Characteristics
＜Level Range＞	Setting the level range
＜MEAS TIME＞	Setting the measurement time (effective range is less than 200 hours).
＜Period＞	Setting the measurement interval for timer-based measurement (effective range is less than 200 hours).
＜Total Time＞	Setting the total measurement time for timer measurement (effective range is less than 200 hours).
＜Start Time＞	Setting the start time for timer measurement (effective range is less than 24 hours).
＜Timer＞	Timer measurement ON/OFF
<Write a comment>	Write the measurement data to the sound level meter's condition memory.
<Initialization>	Restores the condition memory to factory settings.