Troubleshoot PCS 7 V9.0 SP2 CMT Synchronization Relation Errors

For PCS 7 V9.0 SP2, a message beginning “Cannot edit relation …” during CMT synchronization cannot be diagnosed from the text alone; the original post refers to an attached screenshot that is not available here. Capture the full relation name and synchronization dialog, then inspect the reported CMT/CM comparison before applying changes. Siemens' V9.0 SP1 synchronization guide explains that synchronization transfers selected CMT changes to instances and can replace conflicting instance-specific connections, so do not blindly accept the transfer.

Why the exact relation matters

The report says that a project library and control modules (CMs) were created, then a change was made to the library and Synchronize templates produced “Cannot edit relation …”. The missing screenshot likely contains the relation or object context needed to identify the failure. The post provides no CMT name, affected CM, full error text, changed object, project structure, or synchronization comparison.

Siemens' CMT synchronization guide for PCS 7 V9.0 SP1 describes synchronization as comparing CMTs in the master data library with project CMs and showing differences in a data-transfer dialog. Synchronization behavior depends on the type and location of the change and parameter attributes. This provides context but does not define the specific “Cannot edit relation” error in the V9.0 SP2 report.

Collect a useful diagnostic record

Preserve the complete error text, including the exact relation/object name, and capture the dialog shown immediately before and after the error.
Record the PCS 7 version, Service Pack and Update, CMT name, affected CM instance, and whether the change involved a block, chart, signal, parameter or interconnection.
In the synchronization comparison, inspect the differences for the affected object and identify whether a conflicting instance-specific connection is shown.
Preserve a project backup or version-controlled copy and export/record the comparison before applying transfer operations.
Compare the relation against the CMT definition and affected CM using the documented CMT engineering workflow for the installed version. If the dialog does not explain the relation conflict, stop and obtain the complete screenshot and project-specific diagnostics for technical review.

The available evidence does not verify a repair action for this exact error. Do not delete and recreate CMT/CM relations based on guesswork.

Understand synchronization impact

The PCS 7 V9.0 SP1 guide says that users can deselect differences that should not be adjusted in the data-transfer dialog. It also warns that instance-specific connections that conflict with new connections in the CMT are replaced by the CMT connections. Review the proposed transfer object by object, especially where a CM has intentional instance-specific logic or wiring.

The V9.0 SP1 guide is close to, but not the same as, the reported V9.0 SP2 installation. Use it to understand the documented comparison model, not as proof that all dialog behavior or the relation error is identical in SP2.

Verification

After a confirmed correction, rerun synchronization for the affected type and review the comparison and transfer result. Verify the changed CMT/CM relations and intended connections in the project before any compile, download or runtime test. A synchronization dialog completing successfully does not by itself validate process behavior; use the project's approved engineering checks.

Limitations and Operational Precautions

The precise relation error cannot be identified because the screenshot and complete message are missing. The Siemens CMT guide opened for this research applies to PCS 7 V9.0 SP1, whereas the source reports V9.0 SP2. No verified manufacturer source was found that maps this exact message to a specific correction. Synchronization can propagate type changes to project instances and overwrite conflicting connections. Preserve a backup, review each proposed difference, and avoid downloading unreviewed changes to a live automation system.

Engineer FAQ

What is the likely cause of “Cannot edit relation …”? The available evidence does not establish one. The missing relation name and screenshot prevent a reliable diagnosis.

What information should be captured? Full error text, screenshot, PCS 7 V9.0 SP2 Update level, CMT and CM names, recent type changes, and the synchronization comparison for the affected relation.

Can synchronization overwrite instance connections? Siemens' V9.0 SP1 guide says conflicting instance-specific connections are replaced by connections in the CMT. Review the transfer dialog carefully.

Should I delete and recreate the relation? Not without identifying the relation and verifying the applicable repair procedure; this action could damage intended type/instance relationships.

Does the V9.0 SP1 guide prove the error behavior in SP2? No. It documents synchronization concepts for SP1, not the specific SP2 error reported here.

Technical References

Siemens, Synchronization of individual control module types, PCS 7 V9.0 SP1, Entry ID 109758382, V1.0, 06/2018, procedure and synchronization behavior, pp. 7–9: https://cache.industry.siemens.com/dl/files/382/109758382/att_957504/v1/109758382_CMT_Synchronization_PCS7_V90_SP1_en.pdf
Siemens, Engineering with CMT, PCS 7 V9.0.3, Entry ID 109475748, §3.7 “Synchronization Functionality” (version differs from the reported project): https://support.industry.siemens.com/cs/attachments/109475748/109475748_PCS7_CMT_Engineering_DOC_PCS7V903_en.pdf

Troubleshoot PCS 7 V9.0 SP2 CMT Synchronization Relation Errors