Intelligent Input Expansion Unit from elobau

With this new elobau interface, performance level "d" in accordance with EN ISO 13849-1 is still achieved when safety sensors are connected in series.

Moveable guards such as doors and flaps are monitored with safety switches to ensure the safety of machines and systems. An interface or an input expansion unit can be used to save having to wire them individually in the switch cabinet. This means that only one cable is connected into the safety relay. In most input expansion units, all errors cannot be detected when this cascading process is utilised. This makes it difficult to achieve performance level "d" in accordance with safety standard EN ISO 13849-1.

Exactly for this reason, elobau has equipped the existing interfaces with "intelligence" in the form of control outputs. This allows each error to be reliably detected with an additional monitoring method even when series connection is applied. Thanks to the electronic monitoring of individual channels, even without the use of a standard PLC, performance level "d" can still be reached. The costs of the new interface and the additional measures are negligible compared to wiring the sensors individually.

The ‘intelligent’ interface enables the interconnection of up to four safety switches to one sensor input of the safety relay. The 470 series relay shown in the wiring diagram below has 2 sensor inputs allowing for the connection of 2 input expansion units, thereby enabling up to 8 safety switches to be connected to 1 safety relay.

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If you would like any more information on these or any other products in elobau’s machine safety, level measurement, sensor or operator controls product portfolio, please contact elobau UK: