Problems and Their Possible Solutions - HMM100

HMM100 User Guide

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User guide

You can check the error message via the serial interface by using the ERRS command. In case of constant error, please contact Vaisala technical support.

Problem or Message Likely Causes and Solutions
Measurement not working, any of the following errors active:
  • Temperature sensor open circuit/not calibrated
  • Humidity sensor open circuit/not calibrated
  • Temperature sensor values out of range
  • Sensor(s) damaged or missing. Open the filter and check.
  • Calibration is not done. Calibrate the module.
  • Check the supply voltage of the module.
  • Check the analog output mode using the AMODE command.
Humidity measurement appears to be wrong. The following errors may be active:
  • RH reading too high
  • RH reading too low
  • Check for condensation on the probe and sensor.
  • Check that you are not applying temperature compensation in the measurement system (HMM100 has its own).
  • Check for heat conduction through the cable. Place more cable in the chamber if needed.
  • Check the position of the trimmers.
  • Use the L command to check the currently applied calibration correction.
  • Calibration is not done. Calibrate the module.
The following error is active:
  • Capacitance out of range
  • Sensor broken
  • Sensor disconnected
  • Sensor pins twisted and touching
  • Wrong sensor type inserted
  • Sensor replaced but capacitance not adjusted. Perform a humidity adjustment using the CRH command.
Measurement stops, with the following errors active:
  • Analog output test on, no measurements done
  • MeasTask not calculating (ATEST)
You are testing the analog output using the ATEST command. This is normal; type ATEST to stop the test and remove this error.
Serial line command not working, outputs "Unknown command."
  • Mistyped or unknown command
  • Command not available without using the PASS command first
Cannot connect to serial line, current serial settings of the module are unknown. Perform the following steps to connect:
  1. Set your terminal settings to 19200 8 N 1 (the default settings of the module).
  2. Connect to the service port of the module.
  3. Power up the module, and type "z" on the serial line at least five times.
  4. The module will come online with the default settings, and with the text SERVICE MODE.
  5. Use the SERI command to set the desired serial settings, and use the SAVE command to save them.
Any of the following errors is active:
  • Program checksum error
  • Parameter storage checksum error
  • Sensor coefficient checksum error
  • Current settings checksum error
  • Default settings checksum error
  • Log corrupted
  • Resistance measurement
Internal error. Perform the following steps:
  1. Reset or power cycle the module. Check if the error is gone.
  2. Return the module to factory settings using the FRESTORE command. Check again.
  3. If the error is still active, contact Vaisala technical support.