4、这类设备如接线盒、线端子、螺栓螺母等处。这类故障产生的原因除了设备本身的制作工艺原因外还和安装工艺有关，如有人认为电线和螺钉连接是压的越紧越好，但在二次维修时很容易导致拆卸困难，大力拆卸时容易造成连接件及其附近部件的损害。长期的打火、锈蚀等也是造成故障的原因。根据工程经验，这类故障一般是很难发现和维修的。所以在设备的安装和维修中一定要按照安装要求的安装工艺进行，不留设备隐患。第四类故障点可能发生在PLC系统中的子设备

这类设备如接线盒、线端子、螺栓螺母等处。这类故障产生的原因除了设备本身的制作工艺原因外还和安装工艺有关，如有人认为电线和螺钉连接是压的越紧越好，但在二次维修时很容易导致拆卸困难，大力拆卸时容易造成连接件及其附近部件的损害。长期的打火、锈蚀等也是造成故障的原因。根据工程经验，这类故障一般是很难发现和维修的。所以在设备的安装和维修中一定要按照安装要求的安装工艺进行，不留设备隐患。

5、第五类故障点是传感器和仪表

这类故障在控制系统中一般反映在信号的不正常，这类设备安装时信号线的屏蔽层应单端可靠接地，并尽量与动力电缆分开敷设，特别是高干扰的变频器输出电缆，而且要在PIC内部进行软件滤波。这类故障的发现及处理也和日常点巡检有关，发现问题应及时处理。

6、第六类故障主要是电源、地线和信号线的噪声(干扰)

问题的解决或改善主要在于工程设计时的经验和日常维护中的观察分析。

要减小故障率，很重要的一点是要重视工厂工艺和安全操作规程，在日常的工作中要遵守工艺和安全操作规程，严格执行—些相关的规定，如保持集中控制室的环境等等，同时在生产中也应加强这些方面的管理。4. The fourth kind of fault point may occur in the sub-equipment of PLC system



Such equipment as junction box, wire terminal, bolt and nut, etc. The causes of such failures are not only related to the manufacturing process of the equipment itself, but also related to the installation process. For example, some people think that the tighter the wire and screw connection is, the better, but it is easy to cause difficulties in disassembly during secondary maintenance, and it is easy to cause damage to the connector and its nearby components during heavy disassembly. Long-term sparking and corrosion are also the causes of the failure. According to engineering experience, such failures are generally difficult to find and repair. Therefore, the installation and maintenance of the equipment must be carried out according to the installation process required by the installation, without leaving any hidden danger of the equipment.



5. The fifth type of fault points are sensors and instruments



This kind of fault is generally reflected in the abnormal signal in the control system. When installing this kind of equipment, the shielding layer of the signal line should be reliably grounded at one end, and should be laid separately from the power cable as far as possible, especially the frequency converter output cable with high interference, and software filtering should be carried out inside the PIC. The discovery and handling of such failures are also related to routine patrol inspection. Problems found shall be handled in time.



6. The sixth type of fault is mainly the noise (interference) of power supply, ground wire and signal wire



The solution or improvement of the problem mainly depends on the experience in engineering design and observation and analysis in daily maintenance.



In order to reduce the failure rate, it is very important to pay attention to the process and safety operation procedures of the factory, abide by the process and safety operation procedures in daily work, strictly implement some relevant regulations, such as maintaining the environment of the centralized control room, etc., and strengthen the management of these aspects in production.