There are 3 HMP155 models: A, D, and E.
- Active output models
- Model A has 2 analog voltage outputs
- Model E has RS-485 digital output
- Passive output model
- Model D has a 4-wire temperature measurement (passive) and an analog voltage output for relative humidity measurement
All HMP155 models have RS-485 interface for the service use.
| Feature | HMP155A | HMP155D | HMP155E |
|---|---|---|---|
| Digital RS-485 output | ✔ | ||
| Voltage output for RH | ✔ | ✔ | |
| Voltage output for T | ✔ | ||
| Passive 4-wire for T | ✔ | ||
| RS-485 for service use | ✔ | ✔ | ✔ |