Siemens SIMOCODE pro System Manual page 282

Outputs
Note
The inputs of the analog module are passive inputs, i.e. to configure an
analog input circuit, each input will require an additional, isolated external
current source connected in series. If the output of the analog module is not
being used by another application, it can also be used as a current source
for an analog module input circuit. The "Start value of value range" and the
"End value of value range" of the analog module output have to be set to
65535 for this. Thus, the maximum possible current will always be available
via the analog module output.
6-12
SIMOCODE pro
GWA 4NEB 631 6050-22 DS 03