For DMP74B/DMP74C, the sensor purge must be performed manually 1 hour before adjusting the dew point.
For DMP74A, the reference temperature of the dew point should be −40 ˚C ... −60 ˚C (−40 ˚F ... −76 ˚F).
For DMP74B/DMP74C, the reference temperature of the dew point should be −57 ˚C ... −67 ˚C (−70.6 ˚F ... −88.6 ˚F).
To adjust the dew point:
Set the probe to the reference condition. Follow the stabilization from the graphic display by pressing
Graph. The minimum recommended stabilization time for this critical adjustment is 5 hours.
Perform the manual purge if necessary.
Press the Calibration button on the probe handle (see Figure 1) using, for example, a small screwdriver. The
indicator will switch into adjustment mode. To confirm calibration, press
OK.
Select Td/f and press
Select.
To check the environmental settings, press
Yes. To go to calibration directly, press
No.
To select 1-point adjustment, press
Adjust and then
Select.
When the reading has stabilized at the reference level, press
Ready.
Use the arrow buttons to give the reference value. Then press
OK.
Confirm the adjustment by pressing
Yes. If you press
No, you return to the adjustment mode display and no changes are made.
Wait until the automatic autocalibration has taken place.
When the calibration completes, press
Back to exit the adjustment mode.
To return to the basic display, press
Exit.
Place the screw back onto the calibration button.
To seal the calibration, attach a sticker on the calibration button.
Several autocalibrations may be necessary after this adjustment has been performed until the transmitter reaches full
accuracy.