ERROR OUTPUT CONTROL DEVICE FOR PROGRAMMABLE CONTROLER

摘要

The output data of a CPU is compared with the data of a DIP switch to prevent the false operation of I/O cards caused by the false operation of a user or noise in an input and an output unit. The circuit includes a CPU (20) for designating racks, a comparator (30) for comparing rack selecting data of the CPU and DIP switch data, and a switch unit (40) operated by the output signals of the comprator and the I/O cards. The output signal of the comparator enables a decoder (12) when the data of the CPU and the DIP switch are identical and otherwise drives the switch unit (40) to generate error signal.