Checkline DHT-2 - Manual (Page 4)

4.0 C ALIBRATION
Need information on why and when to perform a calibration.
To calibrate the DHT-2, please perform the following procedure:
1. Turn the instrument On.
2. Remove the four fixing screws on the rear of the instrument. Carfully remove
the rear of the plastic case and set it aside.
3. Locate the 1 K Ohm and 1 M Ohm trimmers.
See photo A.
4. Connect the reference probe of beginning of the
scale (29%) Not sure what this means.
5. Use a slotted screwdriver to adjust the 1 K Ohm
trimmer until the instrument’s LED display
reads approimately 30 on the 0 to 100 scale. See
photo B.
6. Connect the reference probe of the end of the
scale (59%). Not sure what this means.
7. Use a slotted screwdriver to adjust the 1 M Ohm
trimmer until the instrument’s LED display
reads approimately 59 on the 0 to 100 scale.
See photo C.
8. Repeat steps 4 and 6 to verify that the display
reads 30% and 59%, respectively. If necessary
repeat the calibration procedure.
9. Replace the back of the plastic case, being careful
not to squeeze the probe's wires. Replace fixing
screws.
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A
B
C
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