What a Question Mark Means Beside a Block in the CFC Editor

In the CFC V9.0 SP5 offline editor, a yellow question mark means block execution is uncertain because CFC cannot determine a static execution state. One documented example is an interconnected block EN input; this does not mean the block is in error. A red exclamation mark indicates a statically disabled block or a zero written to EN in test mode.

CFC execution indicators

Siemens CFC V9.0 SP5 documents three editor states: no mark for statically executed blocks; a red exclamation mark for statically disabled blocks; and a yellow question mark when execution is uncertain. An interconnected EN input is one reason the editor cannot statically determine whether the block executes.

Interpret the EN input

EN enables or disables block execution. If it is interconnected to a signal whose runtime value can change, offline CFC cannot know the current value and therefore marks execution as uncertain. In test mode, a zero on the EN connection produces the “not executed” indication.

Diagnose the runtime state

Select the block and trace its EN connection to the source signal.
Inspect the online value of EN in test/online mode, along with any runtime-group enable or SFC writes.
Confirm the block's expected behavior when EN is zero and when it is one.
Do not change EN to a constant merely to remove the icon unless that change matches the control design.

Verification

Confirm that the online EN value and runtime-group state explain whether the block executes. Verify the intended output behavior and downstream interconnections under both enabled and disabled conditions.

Limitations and Operational Precautions

The icon reports static execution certainty in the CFC editor, not a fault diagnosis. This reference is CFC V9.0 SP5; icon appearance and details should be confirmed for the installed version.

Technical References

Siemens, CFC for SIMATIC S7 V9.0 SP5, Function Manual, section 10.11 “Defining runtime properties”: https://support.industry.siemens.com/cs/attachments/109782631/s7cfcs7b_en-US.pdf

Related Tags

CFC, EN input, block execution, PCS 7

Engineer FAQ

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Can the source's reported setup be generalized? No. Use it as a clue and verify it against the matching product documentation.

What should be verified after configuration? Test the intended data path, permissions, status and runtime behavior.

Does a working HMI value prove the interface is complete? No. Other faceplate fields or server interfaces may require separate configuration.

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Does this article report a lab test? No. It is based on product documentation and ticket observations.

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What a Question Mark Means Beside a Block in the CFC Editor