The difference between the 2 humidity references must be at least 30 %RH. |
In the active output version of HMP155, you can calibrate and adjust both the temperature (T) and additional T-probe temperature (Ta). |
- Connect HMP155 to a PC.
- Open a terminal program.
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Carry out the chemical purge, if available.
- To set purge on, type PUR.
-
To reset the probe, type RESET.
Wait for 8 minutes before taking measurements.
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Press the ADJ button.
The green LED lights up.
- Remove the filter from the probe and insert the probe into a measurement hole of the dry end reference chamber (for example, LiCl: 11 % RH).
- Type the CRH command and press ENTER.
- Wait at least 30 minutes for the sensor to stabilize.
- Press ENTER a few times to check if the reading has stabilized.
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When the reading has stabilized, type the reference humidity after the question mark
and press ENTER.
>crh RH : 16.6675 1. ref ? RH : 16.4978 1. ref ? RH : 16.3956 1. ref ? 11.25 Press any key when ready ... RH : 11.25 Ref2 ?
The device is waiting for the high end reference.
- Insert the probe into the measurement hole of the high-end reference chamber (for example, NaCl: 75 %RH chamber in the humidity calibrator HMK15). Press any key when ready.
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Let the probe stabilize for about 30 minutes.
You can follow the stabilization by pressing ENTER.
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When stabilized, type the high end reference value after the question mark and press
ENTER.
RH : 75.45 Ref2 ? RH : 75.57 Ref2 ? RH : 75.55 Ref2 ? RH : 75.59 Ref2 ? 75.5 OK
OK indicates that the adjustment has succeeded and the new calibration coefficients are calculated and stored.
- Type the calibration information (date and text) to the memory of the probe.
- Reset the probe with the RESET command.
- Take the probe out of the reference conditions and replace the filter, if needed.