The input and output signal is the information exchange between CNC system and the outside world. The interface is the necessary means to exchange information, and has an important position in the CNC numerical control system. For the CNC device, the signal transmitted from the machine to the CNC is called the input signal, and the signal that the CNC sends to the machine is called the output signal.
Different input / output devices are connected to the CNC system, and the corresponding I/O interface circuit and the interface chip are adopted. Interface chip is generally divided into special chip and general chip. The former dedicated to special input / output device interface, the latter applies in a variety of equipment interface for CNC device, main switching signal including AC digital input / output signal and DC AC I / O and I / O signal simulation.