Over Limit Set; Max Hold; Programmable Off/On/Auto Time; Calibration - Extech Instruments SL120 User Manual

Over Limit Set

Press the up or down LIMIT arrow buttons to set the OVER limit
level as displayed on the LCD. If the measured dB level exceeds
the set limit, the indication will appear in the display and the
over limit signal will appear at the alarm output connector. The
display indication and output signal will remain active as long as the
sound pressure level exceeds the set limit.

MAX Hold

The MAX display indicates and holds the highest dB level measured
since the meter was turned on or since the Max Reset button was
pressed. The time and date of the max reading is also displayed.
To clear the display and start a new measurement session, press the
front panel MAX RESET button. If the measured level exceeds the maximum for the range
selected the MAX display will indicate "OL" (overload).

Programmable OFF/ON/AUTO time

The meter is powered by 8 AA batteries or via an AC adaptor for permanent installations.
Continuous battery life is approximately 240 hours (10 days). By programming the ON/OFF
time, the battery life can be greatly extended (30 days assuming an 8 hour day). The
and OFF times are programmed as described in the initial configuration
paragraph. The meter will operate continuously with the power switch in
the ON position. The ON/OFF time will be controlled by the meter when
the power switch is set to the AUTO position.

Calibration

The sound level meter should be calibrated on a regular basis to assure that the meter's
performance and microphone sensitivity has not change. Some operational directives
require daily calibration checks (OSHA). Extech offers several acoustic calibrators to
perform the calibration.
1. Set the meter to the 60 to 110dB or 80 to 130dB range.
2. Place the external calibrator over the Sound Level
Monitor's microphone and turn the Calibrator on.
3. The meter should read close to the calibrator's dB output
level. Typical Calibrator output levels are 94dB and 114dB.
4. If the meter is within ± 0.2 dB of the calibrator's output, no
adjustment is necessary.
5. Adjust the calibration pot on the rear of the meter to the
proper level.
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