AUTOMATIC DETECTION SYSTEM OF FAILED MODULE IN PLC TO WHICH MULTIPLE MODULES ARE SERIALLY CONNECTED

摘要

PROBLEM TO BE SOLVED: To specify and automatically detect a module with a failed operation to a plurality of stages of modules connected to a PLC.;SOLUTION: A module detection signal is inputted from the PLC 50 to a PLC module 51a at the first stage. Next, PLC modules 51b-51d at respective stages including the PLC module 51a at the first stage return, when the module detection signal for detecting a module connection state is inputted from the prestage side, a module connection signal including connection information of the PLC module to the prestage side in response to this input, and on the other hand, transmit the module detection signal to the poststage side. Next, the PLC modules at respective stages return the module connection signal to be returned from the poststage side to the prestage side. Finally, the PLC recognizes a connection situation of the PLC modules at respective stages by the module connection signals of respective stages to be returned, transmit request signals to the recognized PLC modules, and detects that the PLC module which does not return an acknowledge signal in response to the transmitted request signals is a failed module.;COPYRIGHT: (C)2011,JPO&INPIT