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A large part of any complex SCADA system design is involved with matching the protocol and communication parameters between connecting devices.
There are about 200 such real-time user layer and application protocols. These include both proprietary and non-proprietary protocols, some of which are:
* Allen Bradley DF1,DH, and DH+
* GE Fanuc
* Siemens SINAUT
* Mitsubishi
* Modbus RTU/ASCII
* Omron
* Toshiba
* Westinghouse
The industry is now moving away from many of the old and proprietary protocols. These RTU/PLC protocols are emerging as virtual standards in modern SCADA systems.
Modbus: The point-to-point Modbus protocol has become a virtual standard for RTU and PLC communications. During communication on a Modbus network, the protocol determines how each controller will know device address, recognize a message addressed to it, determine the action to be taken, and extract any information or data attached.
Modbus is a de facto standard in spite of some shortcomings. It cannot,...