BECKHOFF FC7501 - Manual (Page 15)

Configuration
FC750x 15
The Online tab
The Online tab makes it possible to find the current phase of the Sercos ring and to change it. Three red dashes
"---" for the phase indicate a ring that is not closed. A phase indication like "2->3" indicates that a change of phase
is currently in progress, and that it is possible that this may take some time.
The DPRAM (online) tab
If TwinCAT is active, direct read access to the DPRAM of the fieldbus cards is provided for diagnostic purposes.
Following the SERCON816 DPRAM, the ASIC registers appear from address 0x1000.