ZZC
PLC self-inspection signals, many internal devices, most users do not fully play its role.
In fact, it can be fully used to monitor the PLC's own work, or to monitor the control objects.
Here is an idea of using the PLC timer as the watchdog to monitor the operation of the control object.
If PLC is used to control the movement of a moving part, see the movement after the control, the watchdog can be used to achieve monitoring.The method is to timing the watchdog timer while applying control.If the action is completed within the specified time, that is, if the timer does not exceed the warning value, the action completion signal has been received, then it means that the control object is working normally, and there is no alarm.
If the time runs out, the description is not normal, and it can be handled accordingly.
If the each important control link of the control object, with such some guard dog "see", the work of the system will be like the back of the hand, problems, stuck in what link is also easy to find.
There are some other monitoring tasks to do.It is very necessary to monitor a complex control system, especially the automatic control system, and even further self-diagnosis.It can reduce the fault of the system, the fault or find, can improve the cumulative average fault-free running time, reduce the fault repair time, improve the reliability of the system.
