Trimmers
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.
RH: −5 %RH ... +5 %RH
±0 %RH
−1 %RH
+1 %RH
−2 %RH
−3 %RH
−4 %RH
−5 %RH
RH
Figure 9 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!
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.
14
1
+2 %RH
+3 %RH
+4 %RH
+5 %RH
If you use the Insight PC software to adjust the measurement or to
Figure 8 Component Board Adjustment
Trimmer
1
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.
T: −0.3 °C ... +0.3 °C
±0 °C
−0.06 °C
+0.06 °C
−0.12 °C
−0.18 °C
−0.24 °C
−0.3 °C
T
+0.12 °C
+0.18 °C
+0.24 °C
+0.3 °C
M212264EN-B