In the PLC control loop, the command can be sent directly or transmitted through the relay on May 1 For example, if your charge is that the PLC outputs 24 V DC, but your control circuit diagram. The PLC node needs 220 V, so you must add a relay. When the PLC outputs the command, the relay acts, but the control circuit node receives the normally open or normally closed relay point Select whether to use the relay according to the situation

The necessary objects of each cabinet can only be configured according to the number of signals If it's just a simple PLC control cabinet, you basically need these items. If you're in the control cabinet, you still need to see the situation There are other things, for example, you may want some field instruments or low-power control boxes, and you may want to increase the opening Or you want to get the first machine, PLC may need to add switches, etc In China's low-voltage distribution network, distribution cabinets are mostly composed of air switches, AC contactors, leakage protection equipment and so on. In the season with large power consumption in winter and summer, or affected by other factors, the leakage protection facilities of distribution cabinet often trip, which affects the reliability of low-voltage distribution network. Especially in the season of high temperature in summer, the distribution cabinet often trips due to excessive load, which affects people's continuous power consumption. At present, in the process of enterprise operation, various electrical equipment are increasing, especially information technology, which is inseparable from the support of electricity.

In the low-voltage distribution system, large power electronic equipment is increasing, and the overload phenomenon is becoming more and more serious, which further accelerates the aging of equipment and materials; Poor circuit contact will inevitably lead to electrical overheating, affect the normal operation of low-voltage power supply and distribution system, damage equipment, and finally affect the safe operation of the whole power supply system. The design capacity of power supply and distribution system is small, lagging behind the rapid growth of power consumption