REMOTE REDUNDANT SYSTEM AND CONTROL METHOD IN PLC

摘要

The present invention relates to a PRC remote redundancy system and a control method. In the related art, a remote slave unit (RSU) can receive data from a master station when the master station is powered off or when communication is lost due to disconnection of a communication line. Therefore, the output data finally received just before the communication interruption can be output through the output module, so it is impossible to control the output value of the remote station in case of emergency such as communication interruption, and to control the input and output in case of abnormal status of the remote station. In addition, there is a problem that the reliability of the remote system is deteriorated because false data due to noise is outputted to the output module without being filtered when it is transmitted through communication. Therefore, the present invention provides two modems (1) (1 ') for data communication with a counterpart station via a communication cable; A transmission / reception module (2) for performing data transmission and reception with a master station by a predetermined protocol; An output data storage section 4 for receiving and storing data to be output to the output card at the master station; An input data storage unit 6 for reading and storing input data from the input module; An emergency output data storage unit 5 for setting and storing an emergency output value; An input / output control module 7 for outputting data to or receiving data from an input / output module I / 0 of a remote station, and controlling input / output card information and attachment / detachment; The system is configured with redundancy using the input / output module 8 which actually performs external device control, and interlock devices are inserted between the remote slave units configured as redundant to monitor each other so that no error data is output in the abnormal state. It prevents malfunctions and improves reliability.