After doing an overall reset of the CPU the "SF DP" LED
As long as no PROFIBUS DP configuration has been loaded into the
CPU the DP section of the CPU will not start.
Upon startup the operating system of the CPU initializes the "SF
DP" LED. The diagnostics buffer of the CPU has no entry for this
Configure a DP master system for the CPU in the hardware
configuration and load this configuration into the CPU.
As soon as a DP configuration is present in the CPU, the "SF DP"
LED no longer lights.