Siemens S7-300 appendix SFC 20 Blkmov, SFC 54 Rddparm

Appendix

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

Note

If you are using SFC 56 "WR_DPARM" or SFC 57 "PARM_MOD", you should always evaluate the SFC's BUSY bit.

•SFC 13 "DPNRM_DG"

On CPUs 312 IFM to 318-2 DP, this SFC always works "quasi synchronously" when it is called in OB82. On CPUs 31xC/31x it generally works asynchronously.

Note

In the user program, the job should merely be started in OB 82. The data should be evaluated in the cyclical program, taking account of the BUSY bits and the value returned in RET_VAL.

Hint

If you are using a CPU 31xC/31x, we recommend that you use SFB 54, rather than SFC 13 "DPNRM_DG".

SFC 20 "BLKMOV"

In the past, this SFC could be used with CPUs 312 IFM to 318-2 DP to copy data from a non runtime-related DB.

SFC 20 no longer has this functionality with CPUs 31xC/31x. SFC83 "READ_DBL" is now used instead.

SFC 54 "RD_DPARM"

This SFC is no longer available on CPUs 31xC/31x. Use SFC 102 "RD_DPARA" instead, which works asynchronously.

CPU 31xC and CPU 31x, Technical data	A-3
Manual, Edition 08/2004, A5E00105475-05