The MODBUS protocol is a master/slave communication bus operating on an RS-485 (MODBUS RTU or MODBUS ASCII) serial line or on Ethernet (MODBUSTCP/ IP). The Master (Client) equipment is PCs or controllers, while the Slaves (Servers) are devices used to detect signals from the field or to intervene in the system to be analysed (DAT3000 series). The Master equipment sends packets of data (queries) to the Slaves. As each Slave device is programmed with a unique address, only the Slave being queried will respond with the data requested. The MODBUS protocol defines the format of the query, which contains address of the slave being queried, a function code that defines the requested action, various fields for exchanging the actual data (registers, coils etc.) and a field that checks for communication errors.
By means of theINMBSMHI001R000, INMBSMHI048O000, INMBSMHI128O000 interfaces, it is possible to integrate Mitsubishi Heavy Industries units with supervision that uses the Modbus standard.