The Kunhang KHDQ series RS485 Modbus digital I/O and relay output module user manual explains features, wiring, register map and code examples.
This manual introduces the Kunhang KHDQ series module, a RS485‑based Modbus digital I/O and relay output device. It details power requirements, physical dimensions, operating temperature, and typical application areas such as HVAC, switch monitoring and remote control.
The document provides a full register address table, wiring diagrams for digital inputs, transistor and relay outputs, and sample Modbus code for reading and writing channels. It also describes the provided configuration software and how to set device address, baud rate and parity. This manual is written in Chinese.
| Power supply voltage | DC 8‑30 V |
|---|---|
| Static power consumption | < 0.05 W |
| Relay supply voltage | 24 V DC (default) |
| Relay coil power consumption | 0.36 W per coil |
| Operating temperature range | -40 °C to +85 °C |
| Module dimensions (small white version) | 96 mm × 50 mm × 31 mm |
| Number of isolated inputs | 16 |
| Number of transistor outputs | 16 |
The module operates from a DC power supply of 8 V to 30 V.
Relays are powered by 24 V DC by default, and each coil consumes 0.36 W when energized.
The module can operate from –40 °C up to +85 °C.
It provides up to 16 isolated digital inputs and 16 transistor digital outputs (various configurations are listed).