Siemens SIMATIC ET 200AL, Системное руководство

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Functions
5.12 Docking systems
PROFINET with STEP 7
Function Manual, 05/2021, A5E03444486-AL
281
• After the feedback "IO device activated", you can access the IO device by means of direct
I/O access.
• Call the "D_ACT_DP" instruction to activate and deactivate the IO device as close as
possible to the start of the OB 1 cycle.
Note
Number of alternating IO devices during operation ("alternating partner port") -
number of docking units
If you wish to achieve the shortest possible tool changeover times, you must observe the
following points that are dependent on the CPU or the CP that is being used:
•
Only those IO devices that have been configured with the PROFINET function
"Prioritized startup" can start up in an optimized fashion. The number of IO devices
with configuration for this PROFINET function is restricted.
• Only a limited number of IO devices can be activated at the same time. This number
depends on the available "D_ACT_DP" resources. A docking unit should not contain
more than the corresponding number of IO devices. If more IO devices are operated in
a docking unit, the IO devices must be activated one after the other, which takes
correspondingly longer.
Example: An S7-CPU 1516-3 PN/DP can operate a maximum of 32 IO devices with
prioritized startup and can simultaneously activate 8 IO devices by means of "D_ACT_DP".
Therefore, for a scheduled optimum use, a docking unit should include no more than 8 IO
devices and no more than 32 IO devices should be used in all the alternating docking
units.