OMRON SYSMAC C40H Programmable Controller

A PC (Programmable Controller) is basically a CPU (Central Processing Unit) containing a program and connected to input and output (I/O) devices. The program controls the PC so that when an input signal from an input device turns ON, the appropriate response is made. The response normally involves turning ON an output signal to an output device. The input devices could be photoelectric sensors, pushbuttons on control panels, limit switches, or any other device that can produce a signal that can be input into the PC. The output devices could be solenoids, switches activating indicator lamps, relays turning on motors, or any other devices that can be activated by signals output
from the PC.