Technical data

Table Of Contents
SFCs for Distributed I/Os or PROFINET IO
System Software for S7-300/400 System and Standard Functions - Volume 1/2
16-10
A5E00709327-01
16.3 Deactivating and Activating DP Slaves/PROFINET IO
Devices with SFC 12 "D_ACT_DP"
Description
With SFC 12 "D_ACT_DP, you can specifically deactivate and reactivate
configured DP slaves/PROFINET IO devices. In addition, you can determine
whether each assigned DP slave or PROFINET IO device is currently activated or
deactivated.
If you use SFC 12 to deactivate an IE/PB Link PN IO, then all subordinate
PROFINET IO devices will also cease to function. These failures will be reported.
SFC 12 cannot be used on PROFIBUS PA field devices which are connected by a
DP/PA link to a DP master system.
Note
As long as any SFC 12 job is busy you cannot download a modified configuration
from your PG to the CPU (during a CiR process).
The CPU rejects initiation of an SFC 12 request when it receives the download of a
modified configuration during a CiR process.
Purpose
If you configure DP slaves/PROFINET IO devices in a CPU which are not actually
present or not currently required, the CPU will nevertheless continue to access
these DP slaves/PROFINET IO devices at regular intervals. After the slaves are
deactivated, further CPU accessing will stop. With PROFIBUS DP, the fastest
possible DP bus cycle can be achieved in this manner and the corresponding error
events no longer occur.
Application Examples
From a machine builder’s point of view, there are numerous device options
possible in series production of machines. However, each delivered machine
includes only one combination of selected options.
Every one of these possible machine options is configured as a DP
slave/PROFINET IO devices by the manufacturer in order to create and maintain a
common user program having all possible options. With SFC 12, you can
deactivate all DP slaves/PROFINET IO devices which are not present at machine
startup.
A similar situation exists for machine tools having numerous tooling options
available but actually using only a few of them at any given time. These tools are
implemented as DP slaves/PROFINET IO devices. With SFC 12, the user program
activates the tools currently needed and deactivates those required later.