YPG109BU 3ASD489306C437 ABB

The shielding layer,the ground wire and the ground may form a closed loop.Under the action of the changing magnetic field,an induced current will appear in the shielding layer,which interferes with the signal loop through the coupling between the shielding layer and the core wire.If the system ground is confused with other grounds,the resulting ground circulation may produce unequal potential distribution on the ground wire,affecting the normal operation of logic circuits and analog circuits in the PLC.The logic voltage interference tolerance of PLC operation is low,and the distribution interference of the logic ground potential can easily affect the logic operation and data storage of the PLC,resulting in data confusion,program runaway or crash.The distribution of the analog ground potential will lead to a decrease in the measurement accuracy,causing serious distortion and malfunction of the signal measurement and control.

屏蔽层、接地线和大地有可能构成闭合环路，在变化磁场的作用下，屏蔽层内又会出现感应电流，通过屏蔽层与芯线之间的耦合，干扰信号回路。若系统地与其它接地处理混乱，所产生的地环流就可能在地线上产生不等电位分布，影响PLC内逻辑电路和模拟电路的正常工作。PLC工作的逻辑电压干扰容限较低，逻辑地电位的分布干扰容易影响PLC的逻辑运算和数据存贮，造成数据混乱、程序跑飞或死机。模拟地电位的分布将导致测量精度下降，引起对信号测控的严重失真和误动作。