Siemens S7-300 Changed behavior of certain SFCs, DPV1, Hereafter called, Firmware Hardware

Appendix

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

... then please note if you upgrade to one of the following CPUs

CPU	Order number	From version		Hereafter called
		Firmware	Hardware
312	6ES7312-1AD10-0AB0	V2.0.0	01	CPU 31xC/31x
312C	6ES7312-5BD01-0AB0	V2.0.0	01
313C	6ES7313-5BE01-0AB0	V2.0.0	01
313C-2 PtP	6ES7313-6BE01-0AB0	V2.0.0	01
313C-2 DP	6ES7313-6CE01-0AB0	V2.0.0	01
314	6ES7314-1AF10-0AB0	V2.0.0	01
314C-2 PtP	6ES7314-6BF01-0AB0	V2.0.0	01
314C-2 DP	6ES7314-6CF01-0AB0	V2.0.0	01
315-2 DP	6ES7315-2AG10-0AB0	V2.0.0	01
315-2 PN/DP	6ES7315-2EG10-0AB0	V2.3.0	01
317-2 DP	6ES7317-2AJ10-0AB0	V2.1.0	01
317-2 PN/DP	6ES7317-2EJ10-0AB0	V2.3.0	01

Reference

If you intend to migrate from PROFIBUS DP to PROFINET, we also recommend the following manual: Guide: From PROFIBUS DP to PROFINET IO

See also

DPV1 (Page 3-32)

A.1.2 Changed behavior of certain SFCs

SFC 56, SFC 57 and SFC 13 which work asynchronously

Some of the SFCs that work asynchronously, when used on CPUs 312IFM – 318-2 DP, were always, or under certain conditions, processed after the first call ("quasi-synchronous").

On the 31xC/31x CPUs these SFCs actually run asynchronously. Asynchronous processing may cover multiple OB1 cycles. As a result, a wait loop may turn into an endless loop within an OB.

The following SFCs are affected:

•SFC 56 "WR_DPARM"; SFC 57 "PARM_MOD"

On CPUs 312 IFM to 318-2 DP, these SFCs always work "quasi-synchronously" during communication with centralized I/O modules and always work synchronously during communication with distributed I/O modules.

A-2	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05