407730 Datasheet, PDF (3/6 Pages) Extech Instruments Corporation. – Digital Sound Level Meter

Operation
1. Power the meter by pressing the power button. The meter will begin displaying
sound level readings. If the LCD does not switch on, check the 9V battery located in the
rear battery compartment.
2. Hold the meter away from the body.
3. View the measurement on the meter’s display. If the meter is in the autoranging mode,
the display may briefly indicate “HI” or “LO” if the noise level is above or below the
currently selected range. The meter will change the range as needed to display the dB
level.
‘A’ and ‘C’ Frequency Weighting
Use the ‘A/C’ button to select ‘A’ or ‘C’ frequency weighting.
With ‘A’ weighting selected, the frequency response of the meter is similar to the response
of the human ear. ‘A’ weighting is commonly used for environmental or hearing
conservation programs such as OSHA regulatory testing and noise ordinance law
enforcement. ‘C’ weighting is a much flatter response and is suitable for the sound level
analysis of machines, engines, etc. “A” or “C” icons will appear in the display.
Most noise measurements are performed using 'A' Weighting and SLOW Response.
‘FAST’ and ‘SLOW’ Response Time
Use the ‘F/S’ button to select FAST (125 ms) or SLOW (1 second) response time. Select
FAST to capture noise peaks and noises that occur very quickly. Select the SLOW
response to monitor a sound source that has a consistent noise level or to average quickly
changing levels. “FAST” or “SLOW” icons will appear in the display.
Select Slow response for most applications.
Auto or Manual Ranging
The meter will turn on in the auto-ranging mode and “AUTO” will be indicated on the
display. In this mode the meter will automatically select the best range for the noise level
being measured. If the measured dB level exceeds the range of the meter or the range of
a selected range, “HI” will appear in the display. If the measured dB level is lower than the
selected range, “LO” will appear in the display.
1. Press the RNG button to manually select the range, “MANU” will be indicated on the
display. The four ranges are: 40-70, 60-90, 80-110 and 100-130. Press the RNG button
to step through the ranges.
2. Press and Hold the RNG button for 2 seconds to exit the manual range mode.
MAX HOLD
In this mode the meter only updates the LCD when a higher reading than the one presently
on the display is detected.
1. Press the MAX HOLD button to enter the Max Hold mode.. The “MAX HOLD” icon will
appear in the display.
2. Press the MAX HOLD button again to exit this mode.
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Model 407730 Version 1.4 April 2006