
Modbus RTU
KMtronic KMtronic
KMtronic
Overview
The KMtronic 8-channel relay board is a Modbus RTU controller that switches eight independent relay outputs over an RS485 bus. Used in industrial automation, building control, and energy management installations, the board lets the ModbusCloud Gateway read each relay's live coil state (relay_1_a through relay_8_a via FC01) and write new on/off commands to all eight outputs in a single FC15 transaction. Each relay switches up to 250 VAC/10 A or 24 VDC/15 A. The board's DIP-switch unit ID and direct coil mapping make integration fast and predictable.
Use cases
- Monitor the live state of all eight relay outputs to verify correct switching sequences in automation routines.
- Alert on a relay remaining energised beyond a scheduled window, indicating a stuck contact or missed off-command.
- Track relay switching frequency over time to estimate contact wear and schedule preventive maintenance.
- Verify that load-shedding commands issued from the portal are confirmed by the corresponding read-back coil states.




