Modbus Protocol and SCADALink Products

Modbus protocol (ASCII and RTU) originally developed by Gould Modicon for their PLC family has become a defacto standard in industrial control communications.

A relatively simple protocol, Modbus has been implemented by many manufacturers of instrumentation and control equipment to offer system interoperability. Equipment supporting Modbus protocol variants include PLC’s, RTU’s, VFD’s (Variable Frequency Drives), SCADA Hosts, MMI’s, Flow Computers, Power Meters, Valve Actuators, Intelligent Instruments, and Protocol Converters.

Supported by a wide range of manufacturers, Modbus protocol has been the protocol of choice when a single protocol is utilized in a SCADA communications network. A majority of industrial equipment either supports Modbus directly as a native protocol or via the manufacturer’s or a third party communication cards.

Modbus TCP

More recently Modbus TCP was developed by Modicon has been adopted as industrial Ethernet protocol transporting Modbus protocol over LAN networks. Modbus TCP operating on Ethernet allowed multiple simultaneous Modbus TCP Master connections to the same Modbus TCP Slave Device.  In addition a Modbus TCP device may also be simultaneously be a Master or Slave.

SCADALink products support Modbus RTU and Modbus TCP Protocol.

Sharing Modbus RTU Slave with Multiple Modbus Masters … see more

There is frequently need to share a single Modbus RTU Slave or single Modbus RTU Slave network with Multiple Modbus Masters. This can be achieved with the use of Modbus Serial Port Multiplexers (SS10, SS20, IP100) or Modbus TCP Gateways (IP100, DC100).