The role of the optocoupler in the input and output interface circuits in the PLC application system is:
- Realize the electrical isolation between the site and the PLC host, and improve the anti-interference;
- When the external circuit fails, the external strong electricity invades the host and damages the host;
- Level switching, the field switching signals may have various levels, and the optocouplers convert them into the standard logic levels required by the PLC host.
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