User guide

Chapter 5 _______________________________________________________________ Maintenance

VAISALA ________________________________________________________________________ 61

Offset and Gain Adjustments

Offset and gain adjustments are performed in the same way (they differ

only in internal calculations), so this section is valid for both methods.

4. Connect the 25917ZZ HMI41-connection cable to the SERVICE PORT

connector on the HMT120 motherboard (see Figure 11 on page

21).

5. Connect the other end of the connection cable to the EXT connector

located on the bottom of the HMI41 indicator (see Figure 20 on

page 59).

6. Turn on both devices. Wait until the following display appears:

7. Select the appropriate adjustment mode with the ▲ and ▼ buttons.

Select offset adjustment if the humidity is < 65 %RH and gain

adjustment if the humidity is ≥ 65 %RH:

Press ENTER to confirm the selection. A display similar to the

following appears:

NOTE

In case of using a HMT120 transmitter with display option, the text

HMI41 adjustment mode" is shown at the upper row of HMT120

display.

The next sections describe how to perform offset and gain adjustments in

two different ways.

RH %