This manual provides installation, wiring and operation instructions for Acrel's WH and WHD series temperature and humidity controllers used in high‑voltage switchgear, transformer substations and similar equipment. It covers general product information, technical data, wiring diagrams, communication setup and sensor configuration.
The document also details functional options such as heating, fan cooling, fault alarm outputs, RS‑485 communication, and programmable parameters, helping users configure the controllers for reliable temperature and humidity regulation in harsh industrial environments.
| Temperature measuring range | -40.0 °C ~ +99.9 °C |
|---|---|
| Humidity measuring range | 0 % ~ 99 % RH |
| Humidity control precision | ±4 % RH |
| Power supply | AC 250 V / 5 A |
| Basic power consumption | 0.8 W |
| Relay power consumption (per channel) | 0.7 W |
| Maximum sensor‑controller wiring length | 20 m (general), 10 m (RS‑485 mode) |
| Communication interface | RS‑485, MODBUS (RTU) |
The connecting wire length between sensor and controller should not exceed 20 m (10 m when using RS‑485 communication).
The controller provides an RS‑485 port and supports MODBUS (RTU) communication.
The basic power consumption of the controller is 0.8 W, with each relay consuming 0.7 W.