PLC电控柜不执行程序该怎么办？
What does the PLC control cabinet do not execute the program?
一般情况下可依照输入---程序执行---输出的步骤进行检查
In general, it can be checked according to input -- program execution -- output steps.
1、输入检查是利用输入LED指示灯识别，或用写入器构成的输入监视器检查。当输入LED不亮时，可初步确定是外部输入系统故障，再配合万用表检查。如果输出电压不正常，就可确定是输入单元故障。当LED亮而内部监视器无显示时，则可认为是输入单元、CPU单元或扩展单元的故障。
1, input check is based on input LED indicator recognition or input monitor composed by writer. When the input LED is not bright, it can be initially determined that the external input system fails, and then the multimeter is checked. If the output voltage is abnormal, the input unit fault can be determined. When the LED is bright and the internal monitor is not displayed, it can be regarded as a failure of the input unit, CPU unit or expansion unit.
2、程序执行检查是通过写入器上的监视器检查。当梯形图的接点状态与结果不一致时，则是程序错误(例如内部继电器双重使用等),或是运算部分出现故障。
2, the program execution check is checked by the monitor on the writer. When the contact state of the ladder diagram is inconsistent with the result, it is a program error (for example, the dual use of internal relay), or the operation part fails.
3、输出检查可用输出LED指示灯识别。当运算结果正确而输出LED指示错误时，则可认为是CPU单元、1/0接口单元的故障。当输出LED是亮的而无输出，则可判断是输出单元故障，或是外部负载系统出现了故障。
3. The output check can be identified by the output LED indicator. When the result is correct and the output LED indicates the error, it can be regarded as a failure of the CPU unit and the 1/0 interface unit. When the output LED is bright without output, it can be judged that the output unit fails or the external load system fails.