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Entry type: FAQ Entry ID: 32202151, Entry date: 01/08/2009

What should you watch out for when using F block types with S7 F systems V 6.0 and FC 0 or SFC 0 in the project?

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When using F block types with S7 F systems V6.0 and CFC V7.0 SP1, it might happen that compilation in CFC with the "Changes" option enabled is not executed completely. Subsequent compiling with the "Entire program" option enabled can lead to a change in the overall signature of the safety program, even if there were no changes in the safety program. A subsequent delta loading might mean that the safety mode can no longer be enabled. You can enable the safety mode again with a Full Shutdown and Restart of the safety program on the F_SHUTDN block.

When should you expect this behavior?
You should only expect this behavior if you are using F block types with S7 F systems V6.0 and CFC V7.0 SP1, and at the same time block FC 0 or SFC 0 is in the project. FC 0 is generally in projects created with PCS7.

How can you avoid this behavior?
There are two ways of avoiding this behavior.

Option 1: Remove blocks FC 0 and SFC 0 from the project
You can avoid this behavior by removing the FC 0 and SFC 0 blocks from your project. Please proceed as follows:

  • Prevent CFC from incorporating FC 0. For this, in the CFC menu Tools -> Settings -> Compilation/Download you set the FC numbers from 0 to xxx in Areas Reserved for Other Applications.

    Fig. 01
  • Do not create the FC 0 as user FC. If you have used FC 0, then rename it.
  • Prevent the incorporation of SFC 0 in CFC charts. If you are using SFC 0 in the project, you call it, for example, via a new FC/FB and then delete SFC 0 from the block folder (when calling in an FC, pay attention to the permissible data types when transferring parameters). Then in the CFC menu Tools -> Block types... you click on the Arrange... button.
  • Compile the CFC chart with the Entire program option enabled.

You can only transfer these changes to the F CPU via a complete download.

Option 2: Restrict Multiuser Engineering
If you cannot make a complete download (with CPU STOP), you can operate F block types and the FC 0 and SFC 0 blocks together in your project. For this you must take restrictions to Multiuser Engineering into account. Restrictions:
In a project that contains a safety program according to the HW Config, you must ensure that no Engineering takes place in CFC while generating or loading processes are running.

Proceed as follows to use this option.

Note: Point 1 is to be performed for each user of the ES. Points 2 and 3 are to be performed once per project.

  1. Then you start the S7F-FC0.exe file. Check the option Allow F-Block types and FC0/SFC0 Blocks and click on the OK button. You terminate the program by clicking on the Close button.

    Fig. 02

  2. Make a fake change in the CFC (for example, change the standard parameters and then undo this change).
  3. Compile the CFC charts with the Changes option enabled.
  4. Now you can continue to use the safety program as usual. It is not necessary to reload the safety program.

S7F-FC0.ZIP ( 52 KB )

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