Operation; Pinless Moisture Measurements; Alarm Settings - Extech Instruments MO257 User Manual

Operation

Pinless Moisture Measurements

1. Press the power button to turn the meter on.
2. Before first use the meter must be calibrated to a known dry area as described below.
3. To calibrate, press the MEAS button immediately after powering the meter. The
display will audibly beep and visually flash the CAL display icon. Keep the
measurement sensor at least 3 to 4" (8 to 10 cm) from any object during calibration.
4. When the calibration is complete the beeping and flashing stop. The calibration
reading must not exceed 0.5. If so, re-calibrate ensuring that hands or other objects
are kept clear of the measurement sensor.
5. The meter should be calibrated whenever it is moved from one measurement area to
another.
6. To take a measurement, hold the meter and position the sensor so that it is very near
or directly touching the surface under test. The meter can sense moisture to a depth
of 0.79 to 1.57" (20 to 40mm).
7. IMPORTANT NOTE: The position of the hand can greatly affect a reading. Do not
move or reposition the hand that holds the meter while taking measurements or when
calibrating the unit.
8. The LCD indicates a relative moisture reading in numeric digits from 0.0 to 100.0 and
with programmable alarm alerts (DRY, RISK, and WET).
9. Press the MEAS button to hold (freeze) a reading on the LCD (the HOLD icon will
appear on the LCD). The meter will hold the reading for 30 seconds before
automatically shutting the meter down.
10. The MAX and MIN display areas indicate the highest and lowest readings
encountered since the measurement session was started.
11. If the battery symbol appears or if the meter does not switch ON, replace the
batteries.

Alarm Settings

Two high alarm points can be set for Moisture measurements: A RISK Alarm (0 to 50
setting range with a default setting of 30 units) and a WET Alarm (50 to 100 setting range
with a default setting of 60 units).
Moisture Alarm Setup Procedure:
1. Press the SET button. The RISK display icon will appear flashing on the LCD
indicating that a RISK alarm can now be programmed.
2. Use the up/down buttons to select the desired RISK Alarm value.
3. Press the SET button when the desired setting is displayed.
4. The WET icon will appear flashing on the LCD indicating that the WET Alarm is ready
to be programmed.
5. Use the up/down buttons to select the desired Wet Alarm setting.
6. Press SET to complete the programming.
7. Now, if the moisture measurement is higher than the RISK setting, the meter will beep
once every two seconds and if the moisture measurement is higher than the WET
setting the meter will beep four times per second.
3 MO257 V1.0 04/10
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