Vaisala HM70 - Manual (Page 53)

Chapter 9 ______________________________________ Calibration and Adjustment of Transmitters
VAISALA _______________________________________________________________________ 51
13. Enter correct reference value by using the arrow buttons. Press
OK .
14. Confirm by pressing YES.
15. Adjustment is done. Press BACK and EXIT to return to the
basic display.
16. Replace the jumper to CAL.RH pins.
17. Switch off HM70 and detach the calibration cable from MI70
and from the transmitter.
2-Point Adjustment by Using a
Calibrator
Note that the difference between the two reference humidities shall be
at least 50 %. MI70 indicator is used now as a communicator. HMP70
probe can be connected or it can be removed while making this
adjustment.
If you use humidity calibrator HMK15, please use the adapter fitting
(13.5 mm) on the measurement hole if you calibrate probes of
HMT324, HMT325, HMT327 and HMT328.
Follow the steps from 1 to 8 and continue as follows:
9. Remove the filter from the transmitter's probe and insert the
probe into lower reference humidity.
10. Press ADJUST to continue adjusting .
11. Select 2-point adjustment , press SELECT.
12. Press READY when the reading is stabilized in the first
reference condition (takes about 30 minutes or more) .
13. Enter correct reference value by using the arrow buttons. Press
OK .
14. Remove the probe and insert the probe into higher reference
humidity. You can follow the stabilization from the GRAPH
display (takes about 30 minutes or more).
15. Press READY when the reading is stabilized in the second
reference condition .
16. Give the higher reference humidity value by using the arrow
buttons. Press OK .
17. Confirm the adjustment, press YES (by pressing NO you
return to adjustment mode display and no changes are made). If