Modbus is a serial communications protocol commonly used by PLCs (programmable logic controllers) and other industrial control systems. While originally based on traditional serial communication, many extensions exist to allow communication over other networks such as TCP/IP.
Modbus is a serial communication protocol commonly used by PLCs (programmable logic controllers) and other industrial control systems. While originally based on traditional serial communication, many extensions exist to allow communication over other networks such as TCP/IP.
See Wikipedia's article on Modbus for more information.
Note that Modbus has replaced its "master/slave" terminology with "client/server", respectively:
Modbus communications [are] characterized by communication between client device(s), which initiate communication and make requests of server device(s), which process requests and return an appropriate response (or error message).
