Siemens SIMATIC ET 200M Operating Instructions Manual page 203

Structure of the channel-related diagnostic
Figure 9-6
Overflow of channel-related diagnoses
If there are more channel-related diagnoses than can be shown in the slave diagnosis, then
the bit 7 "diagnosis overflow" is set in the station status 3.
The channel-related diagnoses that are not transferred with the message frame are not lost.
They follow on to the slave diagnosis as soon as other channel-specific diagnoses that are
entered in the diagnostic frame have gone.
Once the "diagnosis jam" has been worked off, the bit 7 "diagnostic overflow" is reset.
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
Structure of the channel-related diagnostics
Interrupt, error and system messages
9.1 PROFIBUS DP
201