| 摘要 |
PROBLEM TO BE SOLVED: To provide a PLC device allowing certain and easy failure diagnosis of a bus signal and allowing confirmation of presence/absence of mounting of an end cover by equipping a bus interface (hereinafter bus I/F), a register for a bus function, and a bus failure-diagnosing register in the end cover of the PLC device. SOLUTION: A CPU unit communicates with the bus I/F 61 of this end cover 6 in start-up or at prescribed time intervals, and reads end cover peculiar information 621 of the register 62 for the bus function to confirm the presence/absence of the end cover 6. The CPU unit communicates with the bus I/F 61 of the end cover 6 at prescribed time intervals, writes prescribed failure diagnostic data into the bus failure-diagnosing register 63, thereafter reads the failure diagnostic data from the bus failure-diagnosing register 63, and compares the previously stored failure diagnostic data and the read failure diagnostic data to diagnose failure of a bus. COPYRIGHT: (C)2011,JPO&INPIT |
