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S7 Distributed Safety -- Product information -- Technical data
How do you incorporate the execution times of the F blocks for the Mobile Panel 277F IWLAN into the "S7fcotia.xls" table?
Why does my F system go into STOP at startup?
F Technology CPU 300/400 -- Product information -- Technical data
How in the SET do you import and export safety-related characteristic values of SIEMENS components and components from other manufacturers?
Where can you find images, graphics, symbols and screenshots for SIMATIC industrial automation systems?
What are the system limits in an F CPU for safe bidirectional data communication using S7 Communication?
How do you incorporate the execution times of the F blocks for the Mobile Panel 277F IWLAN into the "S7fcotia.xls" table?
Why does my F system go into STOP at startup?
Which values can you use with F CPUs and products of the ET 200 family for PFD, PFH and the proof test interval?
Which fail-safe signal modules of the distributed I/O can be combined with which fail-safe controllers?
Which hardware and software components are required to set up and operate an F system with SIMATIC S7-300F?
Why does my F system go into STOP at startup?
Part number:

Description:
When using S7 Distributed Safety V 5.4 SP1 to V 5.4 SP3, despite correct setting of the monitoring times it still might happen that when the F system starts up, the F CPU goes into STOP. In this case, you find the following entries in the diagnostics buffer:

  • "Cycle time exceeded" or
  • "Error in the safety program: cycle time exceeded".

Note:
With S7 Distributed Safety V 5.4 SP1 the behavior described can only occur when you are using an F CPU that supports "Startup protection in case of inconsistent safety program" (see Product Information for F CPU concerned).

The F CPU's operating mode STOP depends on the following:

  • Number of F peripherals addressed in the safety program.
  • Available time buffer in the value configured for the maximum cycle time of the F runtime group (F monitoring time).
  • Available time buffer in the value configured for the cycle monitoring time (in the "Cycle/Clock marker" tab in the Object Properties of the F CPU).

Remedy:
Execute the steps as in the table below.
 
No. Procedure Note
1 First check whether you have set the monitoring time correctly. Also refer here to the Excel file on response time calculation, s7cotia.xls, Entry ID 25412441.
2 Change to S7 Distributed Safety V 5.4 SP4. Instructions for this are available in the programming and operating manual "S7 Distributed Safety, Configuring and Programming", Edition 10/2007.
3 Generate the safety program with S7 Distributed Safety V 5.4 SP4.  

Keywords:
Safety Integrated, Fail-safe

 Entry ID:27832833   Date:2008-01-29 
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