Process input/output system

摘要

A process input/output system for a sequence controller includes integrally an input portion having a data reading portion for reading an external input signal from an external unit, an input control portion for judging an input condition of the external input signal from the read signal, and a first data memory for storing an input condition determined by the input control portion an output portion having a second data memory for storing output data inputted from a bus of the sequence controller to an external unit, and an output control portion for outputting the stored data to the external unit and holding the stored output data; a preset portion for presetting the selection of whether the unit is to be used as an input unit or as an output unit, the selection of the number of input terminals and output terminals and input response time; and a bus controlling portion for controlling the bus to perform exchanges of data between the first and second data memories and the bus, respectively. The system can respond flexibly according to the change of the input and/or output specifications or the specifications of the sequencer itself.