To check out if a misconduct originates from an input card, you have the possibility to mute/deactivate single input cards.
To do this, please connect static 24V at IN2, so the monitoring on this card is deactivated
See also page 12 off https://www.dina.de/wp-content/uploads/2016/11/dnds-modular-d-e-n.pdf „Disable monitoring - If one monitoring system should be disabled, this could be done by connecting the input IN2 to 24V“