Modbus

Modbus is a communication protocol developed by Modicon in 1979 for serial communication between PLCs. It has become the de facto standard for industrial automation and building management systems (BMS) in the built environment, including data centres.

Two variants are common in datacentre BMS integrations: Modbus RTU, which operates over RS-485 serial links; and Modbus TCP, which wraps the same register-based protocol over standard IP networks. Modbus uses a master/slave architecture — the master (typically a BMS controller or DCIM platform) polls slave devices (CDUs, chillers, generators, environmental sensors) by reading coils, discrete inputs, input registers, and holding registers.

PODVIEW's BMS integration layer supports Modbus RTU and TCP for third-party hardware that does not expose SNMP or BACnet interfaces — common in legacy generator controls, early CDU generations, and specialist cooling equipment from European manufacturers.