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ITGlossary · Communication and monitoring
Modbus
A communication protocol used for connecting industrial electronic devices, including UPS systems.
Technical level:Advanced
It is an open, simple protocol that has been widely used in industrial automation for decades. It runs either over an RS-485 serial link (Modbus RTU) or over Ethernet (Modbus TCP), and lets a central system read values from devices, such as voltages, load, battery status and alarms.
In buildings with a building management system (BMS) or SCADA, Modbus allows the UPS, inverter or stabilizer to appear on the same screen as the air conditioning, generator and fire safety systems. In solar PV it is often used for communication between the inverter, the energy meter and the battery.
To integrate a device you need its register map. Ask for it at the start of the project, together with whether a dedicated card or port is required for Modbus.
Related terms
- RS-485Differential serial interface over a wire pair that links many devices on one bus over long distances, usually with the Modbus RTU protocol.
- Noise (Electrical)Unwanted high-frequency disturbances on the supply voltage, e.g. from motors or power supplies, which UPS systems and line conditioners filter out.
- SNMPA standard network protocol used to monitor and control devices like UPS systems over a network.
- Serial PortA communication port on a UPS used to connect and transmit signals to computers or monitoring equipment.
- RS-232Point-to-point serial communication standard, usually on a DB9 connector, for linking a UPS to one computer over a distance of a few metres.
- USB PortA USB interface used for communication between UPS and computers.