Harmony Control. This voltage monitoring relay monitors a measuring circuit for exceedance or undershoot of the set limit value (80-300 VAC/DC). Two relay changeovers are available for reporting, which can be loaded up to 8 A. A limit value and the response or drop-out delay can be set for each exceedance or undershoot. The settings are made using control elements on the front, which can be protected against changes under a transparent cover. An illuminated scale arrow makes it very easy to see the setting of the potentiometers, even from a distance. The diagnostic switch on the front enables the output relays to be switched off to test the entire application. When the transparent cover is closed, the diagnostic switch is automatically reset. The device is powered from the measuring circuit. Two LEDs show the status. The width is 22.5 mm and it is mounted on a top hat rail. The cable is connected using screw terminals.