One-point humidity calibration and adjustment using handheld meter and HMK15 Humidity Calibrator - HMD110 - HMD112 - HMK15 - HMS110 - HMS112 - HMW110 - HMW112 - TMD110 - TMI110 - TMW110

HMDW110 with TMI110 User Guide

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User guide
  • A fully charged Vaisala MI70 indicator (the measurement display that is included in the HM70 package)
  • Vaisala HMK15 Humidity Calibrator with the preferred salt solution prepared (for example, LiCl (11 %RH) or NaCl (75 %RH))
  • Connection cable for HM70 handheld meter (219980SP)
  • Medium size crosshead screwdriver (Pozidriv)
  1. Prepare the HMDW110 series transmitter for a service port connection.
    1. Open the cover of the HMDW110 series transmitter.
    2. If the terminal block for terminals 5 ... 8 is wired, pull it out.
      This disconnects the transmitter from supply voltage and prevents possible equipment damage that may be caused by ground loops. The locations of the terminal blocks and the service port are shown in HMDW110 series component boards.
    3. If the other terminal block is wired (terminals 1 ... 4), pull it out also.
      This prevents the communication between the transmitter and the Modbus (RS-485) host from interfering with your connection.
  2. Plug in the connection cable 219980SP to the service port of the HMDW110 series transmitter, and the other end to port I of 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, then select Start.
  8. The adjustment mode starts. Select OK.
  9. Select RH as the parameter to be adjusted.
  10. The adjustment mode should now show a stable, unchanging RH value. The difference between the measured value and the reference humidity of the jar should not be greater than the combined measurement uncertainty of the HMDW110 series transmitter and the salt jar.

    Depending on the result, proceed as follows:

    • If the HMDW110 series transmitter is within its accuracy specification, there is no need to proceed with the adjustment. Select Back > Exit to leave the adjustment mode.
    • If adjustment is required, continue with the next step.
  11. Select Adjust > 1-point adjustment.
  12. Select Ready, and use the arrow buttons to enter the correct RH value of the salt jar.

    Select OK when done.

  13. The MI70 will ask Do you really want to adjust?. Select Yes.

    MI70 shows the text Adjustment done and returns to the adjustment mode after a few seconds.

  14. Select Back to return to the parameter selection screen, and Exit to leave the adjustment mode.
  15. Remove the probe from the salt jar and reconnect the filter. Plug the hole on the salt jar.
  16. Turn off the MI70 indicator and disconnect the connection cable from the service port.
  17. Reconnect the terminal blocks and close the cover.