View source for RUT955 Activating DIN1 with relay

This section will provide example how to safely use an external Relay for RUT955 DIN1 (passive/dry) control, when using Common ground: 

[[File:Rut955_activating_din1_with_relay.png]]

Unlike other RUT955 inputs, DIN1 is a passive type and to change its state, pins 1 and 6 must be shorted. This can be done with push button, reed switch or a <b>Relay</b>.  

When using the <b>Relay</b> for input control, one must have in mind, that after <b>Relay</b> deactivation (switching from <b>NO</b> to <b>NC</b>) the COIL still holds energy and can cause high voltage spikes which can, <b>through common ground<sup>1</sup></b>, damage router DIN1 input electronics.  

To avoid this situation always use relays with integrated flyback back diodes or if one is not available, connect <b>External diode</b> parallel to coil contacts in reverse polarity as in picture above.  

When connecting external diode make sure you connect it as close to Relay's coil contacts as possible. 

[[Category:RUT955 Hardware Application Examples]]

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<b><sup>1</sup></b> this scenario is possible1 when RUT955 power supply uses the same ground as Relay Control signal.