Siemens SCALANCE X-300 Configuration Manual page 354

PROFINET IO functionality
6.5 MRP configuration
Special features of the XR-324-12M
Note
PROFINET IO operation of the SCALANCE XR-324-12M
PROFINET IO operation of the SCALANCE XR-324-12M is only possible if there is a media
module inserted in slot 1 of this switch. The factory settings for "mrpdomain-1" specify ports
1 and 2 for MRP so that these two ports need to be made available on the switch by
inserting a media module.
Default of the ring ports with XR-324-12M in the STEP 7 project
With SCALANCE XR-324-12M, the ring ports are set to the first configured ports in the
STEP 7 configuration of MRP if "mrpdomain 1" is selected.
You should therefore check whether the configured ring ports match the connected ring
ports.
354
CAUTION
Configuration Manual, 10/2014, C79000-G8976-C187-22
SCALANCE X-300 / X-400