Programmable logic controller is an industrial control device based on computer technology. It has the characteristics of wide adaptability, small size, low energy consumption, high reliability, simple programming, etc., and is widely used in steel, petroleum, chemical industry, and power , Printing, building materials, machinery manufacturing and other industries. This article mainly introduces the application of PLC in printing press machine and PLC troubleshooting technology.

All kinds of printing press machine have a common feature: all electrical control is controlled by PLC. The small PLC has fewer control points and only 64 operating points. It is an integrated firmware. The large PLC has several thousand operating points and has a split design. The working point can be expanded according to the needs of the number of control points. Large-scale printing equipment adopts split models.

Printing machinery and equipment are composed of host control, water control, ink control, and paper tension control. These control systems are composed of industrial-grade computers or general-purpose computers to achieve fully automatic intelligent centralized operation and automatic control.

According to the different control methods of the host, the printing press machine is divided into two types: shaft machine and shaftless machine. The shaft machine connects all printing towers by a main motor through a main shaft and a belt. The shaftless machine has no physical connection to the main shaft, and is controlled by the computer. Through the optical cable, each virtual motor is organically connected into a printing overall.

The shaft machine is linked by a belt, and the machine's running speed is not high. Only some low and medium speed printing machines are used. The printing machinery market has been slowly discussed. For large and high-precision printing machines, shaftless machines are used. The shaftless machine has become the mainstream of printing press machine due to the flexible printing combination and convenient use and maintenance.

Regardless of whether there is a shaft or a shaftless printing press, PLC control is required. Only one set of PLC is enough for a shaft printing machine; a shaftless printing machine, the main control system, and each printing B-B tower need to be equipped with a PLC system. Depending on the combination printing tower, multiple sets of PLC control systems are used.

PLC is divided into two types: fixed and combined. Fixed PLC, including CPU board, I / O board, display panel, memory block, power supply, etc., all parts constitute an inseparable control firmware. Combined PLC, including CPU module, I / O module, memory, power module, backplane or rack, these modules can be configured in combination according to certain rules or needs.