Vaisala HM70 - Manual (Page 44)

User's Guide ______________________________________________________________________
42 __________________________________________________________________ M210297EN-E
Calibration and Adjustment of HMT100 Series
Transmitters
You can check and adjust the HMT100 relative humidity
measurement with Vaisala HM70 Hand-Held Humidity and
Temperature meter. A HM70-connection cable is needed, Vaisala
order code: 211339.
There are four types of adjustments available: field checking and
adjustment using a calibrated reference probe, one-point adjustment
using a calibrator, two-point adjustment using a calibrator and LiCl-
NaCl adjustment.
Follow the 7 first steps and continue according to the chosen
adjustment method:
1. Connect the 211339 HM70-connection cable to the SERVICE PORT
connector on the HMT100 motherboard.
2. Connect the other end of the connection cable to either of the
HM70's connector ports located on the bottom of the indicator.
3. Turn on both devices (or just the HM70 if HMT100 is on
continuously).
4. The reading of the transmitter is shown on the top or middle row
of the indicator display, depending on which connector port the
connection cable is connected to.
5. Press the ADJ button on the HMT100 motherboard to open the
adjustment mode. The indicator led on the HMT100
motherboard starts flashing. From now on the adjustment is
carried out using the MI70 indicator.
6. Press OK to start adjustment.
7. Check the environment settings if needed. Otherwise press NO .
Continue according to the directions of the desired adjustment
method.
Field Checking and Adjustment
Using a Calibrated Reference Probe
Follow steps 1 to 7 above and continue as follows:
8. Check that the probes are located in equal conditions and wait
until the readings have stabilized (may take 30 minutes or