Operation - Extech Instruments 407780A User Manual

Operation
The meter has two modes of operation, Sound Level Meter mode and Integrating Sound Level
Meter mode.
Sound Level Meter measurements
1. Press the
when the meter was last switched off.
2. Press the A/C button to select the desired frequency weighting.
3. Press the FAST/SLOW/IMPULSE button to select the desired response time.
Note: Refer to local standards to select the proper weighting and response time for the
measurements to be performed. Requirements vary according to country and type of test.
OSHA requires Slow and A weight for many of their workplace tests.
4. Use the ▲▼buttons to select the desired dB range. Choose a setting in which the bar
graph indication registers approximately in the middle of the range. If the OVER indicator
appears during a measurement, the upper limit of the selected range has been exceeded.
Increase the range setting until the symbol remains off during measurements. Similarly, if
the UNDER indicator appears, reduce the range setting until the symbol remains off. Both
indicators are non‐latching and will clear when the correct range is selected.
5. Hold the instrument comfortably in hand (away from the body) or position it on a tripod.
Point the microphone toward the noise source, the sound pressure level will be displayed
on the meter's LCD display
6. The numeric level indication on the display shows the currently measured sound level. The
reading is updated once per second.
7. Press the MAX button to display the maximum sound level encountered during a
measurement period; the MAX indicator will blink appear on the display. Press the MAX
button again to exit this mode
8. Press DATE/TIME to change from current time hour : minute : second display to current
date year – month ‐ day display. The display will revert to the current time display after 2
seconds.
800.561.8187
button to switch the meter ON. The initial state depends on the conditions set
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407780A‐EU‐EN v1.3 4/14