In iSMA Solution, a typical application would be a Master Controller iSMA-B-MAC36NL as a Client communicating with iSMA MIX and MINI I/O Modules (Servers). The simplest configuration is one Client one Server, but a network can be built of one Client with up to 247 servers. Modbus devices are certified by the Modbus User Organization for interoperability and conformance to the Modbus. Numerous automation systems have Modbus-RTU interfaces for communication.
How does Modbus work?ĭevices with Modbus protocol communicate using the Client-Server (Master-Slave) technique, where only the Client can call a query and start a transaction with a server that will answer the queries to the Client with requested data. Modbus-RTU (Remote Terminal Unit) means that the Modbus protocol is used on top of a serial line with an RS-232, RS-485 or similar physical interface. Thanks to the above Modbus as a standard has been adopted by most manufacturers of industrial controllers. Thanks to CRC (cyclic redundancy check) the transmission is checked for errors to provide accuracy.