This document is the user manual of Vaisala HMP45A/D humidity and temperature probes, introducing the probe's usage methods, functions and features
The Vaisala HMP45A and HMP45D probes are designed for measuring relative humidity and temperature. The HMP45A features an active voltage output for temperature, while the HMP45D uses a passive resistive output (Pt 100). Both models utilize a HUMICAP®180 capacitive sensor for humidity and platinum sensors for temperature, protected by a standard membrane filter.
| Humidity Measurement Range | 0.8...100 %RH |
|---|---|
| Humidity Accuracy at +20 °C | +1 %RH (factory) |
| Response Time (90%) | 15 s |
Calibration and maintenance should be performed at regular intervals, with a recommended interval of one year.
No, the HMP45D cannot be used with the HMI41 indicator because the passive temperature signal results in error messages.
With SIGNAL GROUND, the cable can be extended up to 100 metres without disturbing measurement accuracy.