PLC's processing of power supply

The power supply is one of the main ways for interference to enter the programmable controller. 

The power supply interference is mainly generated through the impedance coupling of the power

supply line, and various high-power electrical equipment is the main source of interference.

Siemens 6ES7322-1BH01-0AA0 SIMATIC S7-300 Digital Output Module, Allen Bradley 1756-L55 Processor ROCKWELL 1756-L55M14 , B&R X20DO9322 I/O Module, Siemens 6ES7400-1JA00-0AA0 Expansion Module

In occasions with strong interference or high reliability requirements. 

A shielded isolation transformer and a low-pass filter can be added to the AC power input of the

programmable controller (see Figure 1). The isolation transformer can suppress the external interference from the power line.

To improve the ability to resist high-frequency common-mode interference, the shielding layer should be reliably grounded.

The interested persons of mentioned parts may relate with me, price liberally. --

Vivi (sh_plc@163.com).