Owner manual
One-Point Humidity Calibration and Adjustment
Using a Hand-Held Meter and HMK15 Humidity
Calibrator
n A fully charged Vaisala MI70 indicator (the measurement
display that is included in the HM70 package)
n Vaisala HMK15 Humidity Calibrator with the preferred salt
solution prepared (for example, LiCl (11 %RH) or NaCl (75
%RH)
n Connection cable for HM70 hand-held meter (219980SP)
n Medium size cross-head screwdriver (Pozidriv)
1. Prepare the HMDW110 series transmitter for a service port connection as
instructed in section Connecting to the Service Port on page22.
2. Plug in the connection cable 219980SPto the service port of the HMDW110
series transmitter, and the other end to port Iof the MI70 indicator. If any
other probes are connected to the MI70, disconnect them.
3. Remove the filter on the probe. This exposes the sensors to damage, so
handle the transmitter carefully.
4. Unplug the Ø12 mm hole on the HMK15 salt jar and insert the probe.
5. Wait at least 15 minutes for humidity to stabilize. Stabilization may take a
much longer time if there are temperature differences or the salt solution is
freshly made.
6. Turn on the MI70 indicator.
7. Select Functions > Adjustments from the menu of the MI70 and select
Start.
8. The adjustment mode starts. Select OK.
9. Select RH as the parameter to be adjusted.
10. Theadjustment mode should now show a stable, unchanging RH value.
The difference between the measured value and the reference humidity of
the jar should be no greater than the combined measurement uncertainty of
the HMDW110 series transmitter and the salt jar. Depending on the result,
proceed as follows:
o
If the HMDW110 series transmitter is within its accuracy specification,
there is no need to proceed with the adjustment. Select Back and Exit to
leave the adjustment mode.
o
If adjustment is required, continue with the next step.
11. Select Adjust, and then select 1-point adjustment.
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5 Maintenance