Extech Instruments AN320 User Manual page 9

P4.0: Altitude Pressure Compensation
5. When in setup mode P4.0, press HOLD to enter the pressure compensation parameter. The
LCD will show hPA (unit of measure: hector‐Pascal or millibar) on the lower line and a
flashing 4‐digit number (from 700 to 1990; the default is 1013 hPA which is standard
pressure) on the upper line.
6. Press U/mode to increase the pressure value and L/mode to decrease it.
7. Press HOLD once more to return to P4.0.
8. Press and hold the POWER SET button for 2 seconds to return to the normal operating
mode.
Calibration
CAUTION: Do not calibrate the meter in air with an unknown CO
result in the meter being calibrated to the standard 400 ppm and could lead to inaccurate
results.
1. Place the meter in a calibrated environment.
2. With the meter OFF, press SET, HOLD and L/mode simultaneously to enter CO
mode.
3. The meter will run a 30 second countdown and 'CAL' will show in the lower display.
4. During calibration a CO
5. Wait for approx. 10 minutes for the reading to stop flashing.
6. The calibration is now complete and the meter will return to the normal operating mode.
7. To abort the calibration at any time, turn OFF the meter.
8. If the calibration fails for any reason please return the meter to Extech Instruments for an
evaluation and possible repair.
reading between 380‐420ppm will flash in the upper display.
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concentration. Doing so will
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calibration
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