A.1.2 Changed Behavior Of Certain Sfcs - Siemens Simatic S7-300 Technical Data Manual

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
312
312C
313C
313C-2 PtP
313C-2 DP
314
314C-2 PtP
314C-2 DP
315-2 DP
315-2 PN/DP
317-2 DP
317-2 PN/DP
Reference
If you intend to migrate from PROFIBUS DP to PROFINET, we also recommend the
following manual:
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"
A-2
Order number
6ES7312-1AD10-0AB0
6ES7312-5BD01-0AB0
6ES7313-5BE01-0AB0
6ES7313-6BE01-0AB0
6ES7313-6CE01-0AB0
6ES7314-1AF10-0AB0
6ES7314-6BF01-0AB0
6ES7314-6CF01-0AB0
6ES7315-2AG10-0AB0
6ES7315-2EG10-0AB0
6ES7317-2AJ10-0AB0
6ES7317-2EJ10-0AB0
Guide: From PROFIBUS DP to PROFINET IO
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.
From version
Firmware Hardware
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.0.0 01
V2.3.0 01
V2.1.0 01
V2.3.0 01
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
Hereafter called
CPU 31xC/31x