Vaisala hmt120 - Adjusting Offset and Gain with HMI41

6. Press ON/OFF to finish. These setting are stored in the HMI41 memory; when the HMI41 is
switched on again, it automatically starts up as a calibrator for digital transmitters with
these serial line settings.
After making these settings, continue with the adjustment and follow the
directions of the chosen adjustment method.
6.4.2 Adjusting Oset and Gain with HMI41
Complete the HMI41 calibration setup steps listed in Connections and Selecting
the Calibrator Function (page 62) before starting the adjustment.
Oset and gain adjustments are performed in the same way (they dier only in
internal calculations), so this section is valid for both methods.
1. Connect the 25917ZZ HMI41 connection cable to the
SERVICE PORT connector on the
transmitter's motherboard (see Figure 11 (page 21)).
2. Connect the other end of the connection cable to the EXT connector located on the
bottom of the HMI41 indicator.
3. Turn on both devices. Wait until the following display appears:
4. Select the appropriate adjustment mode with the and buttons. Select oset
adjustment if the humidity is < 65 %RH and gain adjustment if the humidity is ≥ 65 %RH:
Chapter 6 – Calibration and Adjustment
63