How to wire a relay to a PLC?

Generally speaking, factory equipment basically considers the relay output points. The service life of relays is limited. After using for a period of time, they may break down. In this case, you can switch to the spare point and adjust the program appropriately.

1. PLC was a small computer with some technical content in the early days, because it was imported from Japan at that time. Now there are many electricians who know PLC programming, and it is not difficult to find someone to modify the PLC program.

However, program backup is also necessary. After all, it takes time and trial and error to understand the equipment and process flow. Therefore, when a factory buys equipment, it must ask the equipment manufacturer to provide the PLC source code for backup to avoid these embarrassing problems.

2. Generally, most of the broken PLCs are relays in the output circuit, which are very small relays, usually with a coil voltage of 5-24 volts. There are many substitutes in China. As long as the voltage and contacts are the same, the package volume is consistent, and it can be installed, it can be replaced. Replacement can usually solve the problem.

3. When some old masters or old leaders encounter some minor problems with key components, they dare not let their subordinates disassemble them and handle them, for fear of causing big problems.

In fact, electrical products will not cause any trouble as long as you are bold and careful. When disassembling the PLC, the main thing is to prevent the battery and battery cables inside from loosening, otherwise the data will be lost.

Because some PLCs use RAM to store data, you have to be careful about this. There will be no problems elsewhere. When you replace the relay, you only touch the power driver board, not the main board, so it is not a big problem.

4. Replace the relay. Generally, an electric iron and a solder sucker can solve the problem. If the relay is still abnormal after replacement, you can simply follow up on the drive circuit of the relay. Most of them are some devices such as triodes, as well as protection diodes and current limiting resistors. If they are replaced together, they can basically be solved.

5. If you have the program, find the editing software and downloader of this PLC, power on the computer and connect it. It has an online diagnostic function that can directly monitor the output I/O. Change the corresponding output point to the spare point, and then change the external line and it can be used.