In fact, it is an interface component that transmits input and output signals between the PLC and the controlled object. The I/O unit has good electrical isolation and filtering function. The input devices connected to the PLC input interface are various switches, buttons, sensors, etc. The output control devices of PLC are often solenoid valves, contactors, relays, and relays have AC and DC types, voltage and low voltage types, voltage and current types.
The PLC power supply unit includes the power supply of the system and the backup battery. The role of the power supply unit is to convert the external power supply into the internal working voltage. The PLC has a regulated power supply for the PLC's CPU unit and I/O unit. The programmer is the most important peripheral equipment of PLC using the programmer to send the user program into the PLC memory, you can also use the programmer to check the program, modify the program, and monitor the working state of the PLC in addition to adding the appropriate hardware interface and software package on the personal computer, you can use the personal computer to program the PLC using the microcomputer as the programmer. The ladder diagram can be prepared and displayed directly.
