3BSE015195R1 ABB

There are also many examples of failures caused by interference.The interference signal of the system may come from the system itself or from the external environment.Since different systems have strict requirements on grounding,once the grounding resistance or grounding method fails to meet the requirements,the efficiency of network communication will be reduced or the possibility of bit errors will be increased,which will cause some functions to be abnormal at light level.lead to network paralysis.Power quality also affects the stable operation of the system.The power supply used for the system must not only ensure the stability of the voltage,but also ensure that when one power supply fails,it can be switched to another power supply without disturbance,otherwise it will interfere with the system operation.Switching between process control processor master/standby processors can also sometimes cause disturbances.In addition,high-power radio communication equipment such as mobile phones and walkie-talkies can easily cause interference and endanger the operation of the system when working.

干扰造成的故障的实例也不少。系统的干扰信号可能来自于系统本身，也可能来自于外部环境。由于不同的系统对接地都有严格要求的规定，一旦接地电阻或接地方式达不到要求，就会使网路通信的效率降低或增加误码的可能，轻则造成部分功能不正常，重则导致网络瘫痪。电源质量同样影响系统的稳定运行。用于系统的电源既要保证电压的稳定，也要保证在一路电源故障时，无扰切换至另一路电源，否则会对系统工作产生干扰。过程控制处理机主/备处理机之间的切换有时也会导致干扰。另外，大功率的无线电通信设备如手机、对讲机等在工作时，极易造成干扰，危及系统运行。