PM866AK01 ABB

The use of EMI filter can effectively suppress the interference in the power grid from entering the PLC,and can also suppress the interference generated inside the PLC from polluting the power grid.There are two types of power supply interference,one is common mode interference and the other is differential mode interference.Common mode interference is the current flowing into the earth,and differential mode interference is the current between lines.In order to suppress these interference pollution,a filter circuit must be used.In order to suppress common mode interference,it is necessary to connect two capacitors to the ground on the two input lines L and N respectively.Capacitors have a big role in blocking direct traffic(general interference is high-frequency signals,which can be approximated as AC signals).If it is grounded,this part of the interference signal flows into the ground to achieve the effect of filtering.If not grounded,if a person touches it,it will flow into the human body.This is what we understand as leakage.The voltage of this part is AC,generally as high as about 110V,but the leakage current is small.

采用EMI滤波器能有效地抑制电网中的干扰进入PLC，也可以抑制PLC内部产生的干扰污染电网。电源的干扰有两种，一种是共模干扰，一种是差模干扰。共模干扰是流入大地的电流，差模干扰是线与线之间的电流。为了抑制这些干扰污染就必须采用滤波电路，为了抑制共模干扰就需要在输入的两条线L，N线分别接上两个电容到地。电容有一个很大的作用就是隔直通交，（一般的干扰都是高频信号，可以近似的理解为交流信号）。如接地，则此部分干扰信号流入大地，达到滤波的作用。如未接地，人若接触则流入人体。也就是我们所理解的漏电现象。此部分电压为交流，一般高达110V左右，但漏电流较小。