Digital input and output modules each play what role in the PLC control system

plc digital output module is an external control signal or field detection signal processing module to the PLC CPU, an external signal is generally button, proximity switches, limit switches, PLC output module is based on the signal processing logic and internal logic plc program logic controller taken into the , the results of treatment before, switch output signal is output by the high and low output module, to drive external relays, contactors, lights, solenoid valves and other components, thereby enabling the external device corresponding action