Siemens S7-300 SFCs that may return other results, Activating / deactivating DP slaves via SFC

Appendix

A.1 Information about upgrading to a CPU 31xC or CPU 31x

SFCs that may return other results

You can ignore the following points if you only use logical addressing in your user program.

When using address conversion in your user program (SFC 5 "GADR_LGC",

SFC 49 "LGC_GADR"), you must check the assignment of the slot and logical start address for your DP slaves.

•In the past, the diagnostic address of a DP slave was assigned to the slave's virtual slot 2. Since DPV1 was standardized, this diagnostic address has been assigned to virtual slot 0 (station proxy) for CPUs 31xC/31x.

•If the slave has modeled a separate slot for the interface module (e.g. CPU31x-2 DP as an intelligent slave or IM 153), then its address is assigned to slot 2.

Activating / deactivating DP slaves via SFC 12

With CPUs 31xC/31x, slaves that were deactivated via SFC 12 are no longer automatically activated at the RUN to STOP transition. Now they are not activated until they are restarted (STOP to RUN transition).

A.1.3 Interrupt events from distributed I/Os while the CPU status is in STOP

Interrupt events from distributed I/Os while the CPU status is in STOP

With the new DPV1 functionality (IEC 61158/ EN 50170, volume 2, PROFIBUS), the handling of incoming interrupt events from the distributed I/Os while the CPU status is in STOP has also changed.

Previous response by the CPU with STOP status

With CPUs 312IFM – 318-2 DP, initially an interrupt event was noticed while the CPU was in STOP mode. When the CPU status subsequently returned to RUN, the interrupt was then fetched by an appropriate OB (e.g. OB 82).

New response by the CPU

With CPUs 31xC/31x, an interrupt event (process or diagnostic interrupt, new DPV1 interrupts) is acknowledged by the distributed I/O while the CPU is still in STOP status, and is entered in the diagnostic buffer if necessary (diagnostic interrupts only). When the CPU status subsequently returns to RUN, the interrupt is no longer fetched by the OB. Possible slave faults can be read using suitable SSL queries (e.g. read SSL 0x692 via SFC51).

A-4	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05