Potential errors could be
1) LEDs to both sides (left and right) of the in- and output module do not light up
Reason: No measuring system
Sensor error at IN1 or IN2 or at both of them
2) LEDs to both sides (left and right) of the output module do not light up
Reason: E1 or E2 or both oft hem are not connected to 24V
3) LEDs to both sides (left and right) of the output module briefly flash green
Reason: one of the contacts does not close or open
Time setting is not the same in both channels
4) LED on the left or right of the input module flashes at 1Hz
Reason: Track A or B of the measuring system is missing
5) The right LED goes out at a standstill.
Reason: Saving of previous V > Vmax.
-> Acknowledgment by 2 sec. Power off
6) LED on the left or right of the input module flashes at 2Hz
Reason: DNDS malfunction or malfunction due to improperly laid signal lines.
-> Acknowledgment by 2 sec. Power off