HMP240 series Dewpoint Transmitters provide fast and reliable dewpoint measurement especially under high humidity conditions where dew would normally form on the humidity sensor head and thereby cause errors in measurements.
The HMP240 Series dewpoint transmitters are designed for high‑humidity and condensing environments, offering fast, reliable dewpoint measurements by keeping the probe head temperature above ambient to prevent condensation. Two models are available: the HMP243 with a plastic probe for outdoor use and the HMP247 with a pressure‑tight steel probe for demanding industrial applications.
The manual covers technical data, optional temperature sensor options, analog and serial output configurations, installation kits, calibration procedures, and sensor re‑gaining options. It also provides wiring details, power requirements, and environmental specifications to help users install, configure, and maintain the transmitters efficiently.
| Dewpoint temperature measurement range | -40 to +100 °C |
|---|---|
| Optional temperature sensor range | -40 to +180 °C |
| Response time (90% at +20 °C) | 15 s |
| Analog output options | 0.20 mA, 4.20 mA, 0.1 V, 0‑5 V, 0.10 V |
| Serial output | RS‑232C |
| Relative humidity range | 0 %‑100 %RH |
| Power supply | 24 VDC/VAC (20‑28 V), 200 mA max. |
| Probe cable lengths | 2 m, 5 m, 10 m |
The 90 % response time at +20 °C in still air is 15 seconds.
An additional temperature sensor head can be added to measure ambient temperature, enabling calculation of relative humidity, absolute humidity, wet‑bulb temperature and dewpoint difference.