Adjusting RH and T with MI70 handheld indicator - HMT130

HMT130 User Guide

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User guide
  • MI70 handheld indicator (included in, for example, the HM70 package)
  • MI70 connection cable (Vaisala item code 211339)

You can check and adjust the transmitter's relative humidity and temperature measurement with the MI70 handheld indicator, which is included in the HM70 handheld humidity and temperature meter.

There are four types of adjustments available:
  • Field checking and adjustment using a calibrated reference probe
  • 1-point adjustment using a calibrator
  • 2-point adjustment using a calibrator
  • LiCl-NaCl adjustment
Start the adjustment by completing the first 7 steps and then continue according to the chosen adjustment method.
  1. Connect the HM70 connection cable (211339) to the SERVICE PORT connector on the transmitter's component board (see Figure 1).
  2. Connect the other end of the connection cable to either of the MI70 connector ports (port I or port II) located on the bottom of the indicator.
  3. Turn on both devices (or just the MI70 indicator if the transmitter is on continuously).
  4. The reading of the transmitter is shown on the top or middle row of the indicator display, depending on which connector port the connection cable is connected to.
  5. Press the ADJ button on the transmitter's component board to open the adjustment mode. Both LEDs on the component board remain in OFF state and the text Starting adjustment mode for HMP110 is shown on the MI70 display.
    In transmitters with the optional display, the text MI70 adjustment mode is shown on the upper row of the display.
    From this point onward, the transmitter's local adjustment buttons are disabled and adjustment is carried out using the MI70 indicator. The transmitter display and analog outputs will always follow the actual measured RH/T value when in MI70 adjustment mode. When operating the MI70, do not press the buttons too quickly or the calibration may fail. Wait for one second between each press.
  6. Press OK to start the adjustment.
  7. Check the environment settings if needed. Otherwise, press NO. Select RH adjustment or T adjustment.
  8. Continue according to the instructions for one of the following adjustment methods: