PROFIBUS DP
5.1 CPU 41x-3 PN/DP as DP master / DP slave
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0
5-25
Interrupts with a Different DP Master
If you are operating the CPU 41x with a different DP master, these interrupts are simulated
in the device-related diagnostic data of the CPU 41x. You have to process the relevant
diagnostic events in the DP master's user program.
Note
Note the following in order to be able to evaluate diagnostic interrupts and hardware
interrupts using device-related diagnostics when using a different DP master:
● the DP master should be able to save the diagnosis messages, i.e. the diagnosis messages should
be stored within the DP master in a ring buffer. If there are more diagnostic messages than the DP
master can store, then, for example, only the last diagnostic message received would be available
for evaluation.
● You must scan the relevant bits in the device-related diagnostic data in your user program at
regular intervals. You must also take the PROFIBUS DP bus cycle time into consideration so that,
for example, you can query the bits at least once synchronized with the bus cycle time.
● With an IM 308-C operating in DP master mode, you cannot utilize process interrupts in device-
specific diagnostics, because only incoming events are reported, rather than outgoing events.
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