Vaisala hmdw110 series, User Manual

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7.2.1 Adjustment Types
You can perform a one-point calibration and adjustment with Vaisala handheld meters that
utilize the MI70 measurement indicator (for example, HM70).
Connecting to the service port using a computer and a terminal program allows you to
perform calibration and adjustment tasks using serial commands. You can, for example,
perform a two-point humidity calibration and adjustment, or clear the existing user
adjustments (factory calibration will remain).
If you replace the HUMICAP â humidity sensor of the transmitter, you must
perform the two-point humidity calibration afterwards.
More Information
‣ Calibration and Adjustment Commands (page 48)
‣ Calibration and Adjustment Using Handheld Meter and Reference Probe (page 56)
‣ One-Point Humidity Calibration and Adjustment Using Handheld Meter and HMK15
Humidity Calibrator (page 58)
‣
Two-Point Humidity Calibration and Adjustment Using Computer and HMK15 Humidity
Calibrator (page 59)
‣
Two-Point Temperature Calibration and Adjustment Using Computer (page 62)
7.2.2 Adjustment Points
HMDW110 series transmitters have two adjustment points for both humidity measurement and
temperature measurement:
• The first point (low point) affects offset across the entire measurement range. For
humidity adjustment, the low point must be < 50 %RH.
• The second point (high point) affects measurement gain. For humidity adjustment, the
high point must be > 50 %RH.
Additionally, two-point humidity calibration requires that the difference between the two
points is
≥
30 %RH.
Temperature adjustment points must be in range
‑
40 ... +60 °C (-40 ... +140 °F) with more than
30 °C (86 °F) difference.
Chapter 7 – Maintenance
55