Siemens SIMATIC S7-400 Reference Manual page 86

Digital modules
4.3 Assigning parameters to digital modules
Static parameters are passed to digital modules after a STOP ＞ RUN transition of the CPU,
as described above.
You may also edit dynamic parameters in the active user program of an S7 PLC using SFCs.
However, the parameters set in
RUN transition of the CPU. You will find a description of the parameter assignment of modules
in the user program in the Appendix.
Configuration in RUN (CiR)
CiR (Configuration in RUN) is a method you can use to modify your system or edit the
parameters of individual modules. These changes are made while your system is in operation,
that is, your CPU will stay in RUN over a maximum of 2.5 seconds while these changes are
applied.
For detailed information on this topic, refer to the "Configuration in RUN by means of CiR"
manual. This manual is found, for example, as a file in PDF format on the STEP 7 CD supplied.
86
STEP 7 will be applied again after a RUN > STOP, STOP >
Reference Manual, Ausgabe 11/2016, A5E00850736-08
S7-400 Automation System Module Data