Monitoring device for mains monitors

摘要

The system has a single-pole electric signal line (6) connected at ends with an output (4) and an input (5) of a control unit (2). The control unit triggers an action during detected interruption of the signal line. Monitoring devices (7a-7c) are attached to power monitors (Na, Nb, Nc). The monitoring devices are arranged external to the power monitors and self integrated in the power monitors. The control unit is in cooperation with the monitoring devices for checking function and/or functionality of the power monitors. The signal line is formed as a power monitor loop. An independent claim is also included for a method for monitoring power monitors.