REF542PLUS ABB

Description

Feeder terminal REF 542plus

The REF 542plus feeder terminal is a compact digital bay control technology solution. It can be used in several different medium voltage applications, such as in feeder protection, transformer protection and motor protection.

The feeder terminal REF 542plus, like its predecessor REF 542, combines measurement, monitoring, protection, control and self diagnostics in one package. With its integrated communication protocols, the REF 542plus can be easily incorporated into any substation automation system from ABB or third parties.

These new generation devices provide exceptional flexibility and scale-ability resulting in smart and clean solutions compared to more traditional approaches. The software solution allows you to use the REF 542plus in all ABB primary air and gas insulated switchgear solutions.

There are many PLC self-checking signals and many internal devices, and most users do not fully play their role.

In fact, it can be used to monitor the PLC’s own work or the control object.

This paper introduces an idea of using PLC timer as watchdog to monitor the working condition of the controlled object.

If a PLC is used to control the movement of a moving part, the watchdog method can be used to monitor whether the movement has been carried out after the control is applied. The specific method is to time the watchdog timer while applying control. If the action is completed within the specified time, that is, if the timer has not exceeded the warning value, and the action completion signal has been received, it means that the control object is working normally without alarm.

If the timeout occurs, it indicates that it is abnormal and can be handled accordingly.

If all the important control links of the control object are “watched” by such watchdogs, the work of the system will be as clear as the palm of the hand. If there is a problem, it is also easy to find what link is stuck.

There are other monitoring work to be done. For a complex control system, especially the automatic control system, it is very necessary to monitor and further self-diagnosis. It can reduce system failures, make it easy to find faults, improve cumulative mean time between failures, reduce fault repair time, and improve system reliability.