Drop indicator or annunciator relays are used as status indicators in control rooms, on control panels, and in mimic diagrams. Default contact assignments make rapid commissioning possible. That is why semi-automated or fully automated design variants feature clearly arranged display surfaces. Their robust design ensures reliable operation, even under harsh ambient conditions.
The MR 11 annunciator relay is a semi-automatic relay. Apart from the coil excitation voltage, no other auxiliary voltage is required for the visual display. This is particularly important in voltage monitoring applications
The MR 21 annunciator relay is used to indicate dangerous states and operating states. It is fully automatic.
Drop indicator relay with manual message acknowledgment
The semi-automatic drop-indicator or annunciator relay MR 11 is used to display system states.
In this design version, message acknowledgment is performed manually by actuating the reset button mounted on the device front. This enables a clear overview of already known (acknowledged) or changed (not yet acknowledged) messages.
This allows service technicians on site to recognize whether system states are already known and whether appropriate measures have already been taken or whether measures still need to be taken. Upon acknowledgment and fault clearance, the drop indicator relay automatically returns to its original position.
The special feature of the semi-automatic design version is that the fault message on the front of the device is retained after fault clearance without prior message acknowledgment. This enables the service technician to recognize whether uninterrupted system operation was possible, even after the fault has been cleared automatically.
Combination housing for front installation
Our combination housings allow you to easily mount up to nine drop indicator relays in the control cabinet front. The common carrier does not only simplify mounting, but also simplifies the overview of any messages present.
Depending on combination housing, up to four or up to nine drop indicator relays can be mounted. Naturally, you can also install fewer relays than the maximum. In this case, the remaining free slots are simply closed off with dummy plates. This means that you have the option of extending your system at a later date.