Trimmers - HMD65 - HMD60

HMD65 Quick Guide

Document code
English (United States)
Document type
User guide
Figure 1. Component Board Adjustment Trimmer

Use a Phillips head screwdriver to rotate the RH or T adjustment trimmer. To increase the measurement output value, rotate the trimmer clockwise. To decrease, rotate counterclockwise.

Note that there is a slight delay before the measurement output changes after rotating the trimmer.

You can adjust the transmitter's RH or T measurement output with the trimmers on the component board. During trimmer adjustment, the output of the transmitter is corrected using the trimmers until the output matches the known value of a reference.

In order to make an adjustment with the trimmers, you need a reference measurement source. You can either insert a reference instrument into the environment that HMD65 is installed in and compare the readings of the instruments, or remove HMD65 from the installation environment and use a calibration and adjustment tool (for example, Vaisala Humidity Calibrator HMK15) to generate an environment with a known value.

Figure 2. RH and T Trimmer Adjustment Ranges (Indicative)
You can only calibrate the relative humidity measurement (RH) and temperature measurement (T). Other parameters are calculated internally based on RH and T. Check that the output selection DIP switch is set to RH when making adjustments with the physical trimmer; when using the Insight PC software, set all DIP switches to the OFF position. For further information on using the adjustment trimmers, see HMD65 User Guide.
CAUTION If you use the Insight PC software to adjust the measurement or to restore the factory settings, always return the physical trimmer to the middle position before starting. When you make an adjustment with Insight, the position in which the trimmer is at that point is set as the ±0 point.