PLC interferes with isolation measures in the environment
PLC is now a very popular control operating system, many operators are now proficient in the application of PLC control system. PLC control system in the interference environment is no way to work normally and accurately, then what method can isolate the interference, the following instrument world network small editor to introduce the isolation measures in the PLC interference environment for you.
The optical coupler inside the PLC, the small relay in the output module and the photosensitive thyristor and other devices to achieve the isolation of the external switching signal, and the analog I/O module of the PLC is generally also isolated by the optical coupler. In addition to reducing or eliminating the impact of external interference on the system, these devices can also protect the CPU module from the harm of high voltage entering the PLC from the outside, so it is generally not necessary to set interference isolation devices outside the PLC.
In some industrial environments, PLCS are subject to strong interference. Due to the limitations of field conditions, sometimes a very long strong current cable and PLC low-voltage control cable can only be laid in the same cable trench, the induced voltage and induced current generated by the strong current interference on the input line is quite large, enough to make the light-emitting diode in the optical coupler at the input end of the PLC light, the isolation of the optical coupler failure, so that the PLC produces misoperation. In this case, small relays can be used to isolate switching signals introduced into the PLC with a long line. The input signals in the switchgear and not far from the switchgear generally do not need to be isolated by relays.
In order to improve anti-interference ability and lightning protection, the serial communication line between the PLC and the computer can be considered to use optical fiber, or the communication interface with optical coupler.
Safe electrical isolation must be provided between the PLC’s 24 VDC power supply loop and equipment, and between the 120/230 VAC power supply and hazardous environments.
The isolation measures in the PLC interference environment have been introduced, and now we all know what measures there are through the above article, and if there is strong interference in the future use, the above methods can be used to resist interference.