What is Modbus in building automation?
By Bassirou Thiam, building automation engineer · Updated
Modbus is a simple master/slave protocol, over RS-485 (Modbus RTU) or Ethernet (Modbus TCP), widely used by meters, variable frequency drives and packaged equipment. In a BAS it is usually integrated through a supervisory controller or gateway that maps Modbus registers to BACnet points.
On the points list
Integrated Modbus values appear as network points, with their register and scaling noted so the programmer can map them.
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Related
GlossaryWhat is a supervisory controller (JACE)?Definition of a supervisory controller in a BAS, such as a Niagara JACE: the device that manages field controllers and connects them to the front end.
GlossaryWhat is a BAS points list?Definition of a BAS points list (I/O list, points schedule): every input and output per controller, with point type, field device and location.
GlossaryWhat is BACnet/IP?Definition of BACnet/IP: BACnet carried over Ethernet and IP networks, used for the backbone between building controllers and the front end.