Preventive Protection of Emergency Shutdown of a Technological Object Using Meander Signal in PLC

The article describes the implementation of preventive protection for emergency shutdown of technological facilities using a square wave signal in a programmable logic controller (PLC). The advantages of this protection method are presented compared to the method of using internal PLC diagnostics. The structural diagram of the preventive protection system involving the square wave signal for diagnosing the PLC's operability is presented. The necessary modifications of the software are described, as well as recommendations for using additional control elements to implement this method of protecting the technological facility