Trains approaching to a level crossing are detected by one or two train induction loops FSP and its detection modules ESD. The module ARM receives the signal from the ESD and can determine the direction of the train. In the case of an approaching train the module ARM provides a relay pulse of configurable duration.
A supply voltage of either 36V or 60V is required. Subject to the specific requirement of the train approach information the ARM can submit the information dependent on the direction of the train. In this case two induction loops FSP with two modules ESD are used. The information is given by a potential-free relay contact with pulse duration of either 3 sec. or 10 sec.

The module ARM is placed in a plastic housing of protection class IP30. It can be mounted on a standard top-hat rail either in the interlocking or in the housing of the level crossing. The module contains a voltage converter and the circuit arrangement with input circuit, internal logic and output relay. The input signals are received by optocouplers. The status of the inputs (occupied/free) is displayed by several LED on the front of the module.