Cause : Digital output not set comes when despite specification by the signal source the digital output has not been set.

Possible causes:

- power supply missing.
- the digital output is in current limiting (e.g. due to short-circuit).
- The digital output is being used for Safety Extended Functions.
- The control has authority to access the digital output by means of direct access (see also r0729).

1. check the 24 V power supply (e.g. X130.6 for CU310-2, ground is X130.5).
2. check the output terminals for short-circuits.
3. reset the signal source of the digital output for use by Safety Extended functions.
4. carry out a POWER ON (power off/on).