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Entry type: FAQ Entry ID: 5416540, Entry date: 06/06/2007

How do you perform a block-consistency check following changes in the STEP 7 program?

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The block-consistency check is used to scan for inconsistencies caused by changes to interfaces and to rectify them. The table below describes the procedure for checking consistency within the entire block folder or within the entire program in an S7 station.

No. Procedure:
1 In the SIMATIC Manager, mark the block folder within an S7 program and open the "Check block consistency" dialog box;
  • either via the menu command "Edit > Check block consistency ..." or
  • right-click and then select the "Check block consistency ..." function in the pop-up menu that opens.

The structure of your S7 program then appears.

Fig. 01
2 You can check the blocks' consistency in this display. If a block is marked with a red cross (in this example, OB1 and FB1 in Fig. 01), this indicates that there is an interface conflict in that block. The block responsible is marked with a yellow exclamation mark ( FC1, in this case).

In order to determine the precise cause of the interface conflict, compile the entire program either with the menu command "Program > Compile all" or by clicking the "Compile all" button (Fig. 02).

All the blocks are now compiled one after another. If an error occurs during compilation, the cause is flagged up in the output window by a red circle.

Fig. 02
3 The individual blocks are opened by double-clicking the corresponding error messages. The invalid block call is highlighted in red. Update the block call. You can find further information on how to update block calls in our entry entitled
  • "How do you update invalid block calls (time stamp conflicts) in calling blocks?"
    Entry ID: 12216780.

Fig. 03

After the time stamp conflict has been rectified and the block has been saved, the error-related symbol disappears from the reference tree. The program is now consistent.

The block consistency check is currently supported by the following SIMATIC software products:

  • STEP 7 from V5.1 onwards
  • S7-GRAPH from V5.2 onwards
  • S7-HiGraph from V5.2 onwards
  • S7-SCL from V5.3 SP1 onwards
  • S7-PDIAG V5.1

All other programming languages support the consistency check and cannot be compiled with the "Compile all" function.

If the consistency check reveals time-stamp conflicts or interface changes, take the following steps:

  • Double-click the block in question in the SIMATIC Manager to open it and re-compile it with the appropriate compiler.
  • Perform this in consecutive order for all the blocks with time-stamp conflicts and changed interfaces.
  • The block-consistency check is then called again.

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