Modbus: Summary of the Specification (high level)
The Modbus protocol is a communication protocol based on a master/slave or client/server architecture. It was introduced in 1979 by Gould-Modicon for communication with its programmable logic controllers. In industry, Modbus has become a de facto standard as it is an open protocol. Since 2007, the Modbus TCP version has been part of the IEC 61158 standard. [Wikipedia] As the following diagram shows, Modbus allows communication over different networks: ...