Reconciling Master Data Library SFC Type Discrepancies and Compiler Time Stamps in SIMATIC PCS 7

When SIMATIC PCS 7 reports structural or header discrepancies during SFC Type reconciliation between the Master Data Library and AS chart instances, the discrepancy is resolved by executing 'Update Block Types' with 'Conform attributes' enabled. Internal header attributes like BT_ID serve as synchronization anchors. If an engineer encounters discrepancies but process operations remain stable, the difference indicates that the library contains a newer compilation timestamp than the AS block folder. Updating the AS types aligns the compilation timestamps, eliminates compiler warnings, and ensures consistent Delta Download tracking across all stations.

The Role of the Master Data Library in SFC Type Integrity

In a centralized SIMATIC PCS 7 engineering architecture, the Master Data Library (MDL) serves as the authoritative golden repository for all automation building blocks: function block types (FBs), functions (FCs), shared data structures, and SFC Types.

When multiple automation stations (AS) participate in a plant, each station holds local copies of these blocks in its offline Blocks container and CFC chart database. Over time, as different engineers make adjustments or test new library revisions, timestamp skew develops between the MDL and the individual AS stations. Reconciling these differences is essential for long-term maintainability.

Analyzing Comparison Results in the Block Type Update Wizard

When launching the Update Block Types wizard from the Master Data Library, the tool displays a three-way comparison table:

Library Version: The type definition currently stored in the Master Data Library.
Project Version: The type definition currently present in the target AS program's Blocks folder.
Instance Usage: How many instances of this SFC Type exist on Continuous Function Charts.

If the only reported difference is BT_ID, the underlying interface (inputs, outputs, characteristics, setpoints) is 100% identical. The discrepancy reflects solely that the library object was recompiled or saved at a later timestamp.

Header Attributes vs Interface Pins: Critical Distinction

When reviewing reconciliation reports, engineers must distinguish between benign and breaking differences:

Benign Discrepancies: Changes in BT_ID, Author, Version string, or comments. These do not alter memory offsets and can be downloaded safely in RUN via Delta Download.
Breaking Discrepancies: Added, deleted, or reordered input/output parameters, altered data types (e.g., BOOL to BYTE), or structural changes in sequential steps. These alter instance DB layouts and can mandate an entire AS compilation and full download.

Step-by-Step Procedure to Align Library and Project Types

To align SFC Types cleanly across the Multiproject:

Audit Master Data Library: Open the SFC Type in the Master Data Library. Review the revision notes and verify that the type definition is approved for production.
Open Block Type Update: In SIMATIC Manager, select the Master Data Library, then click Options > Charts > Update Block Types.
Select SFC Types: In the list of types, select the relevant SFC Types (or select all).
Select Target AS Stations: Choose all AS stations in the Multiproject to maintain universal version alignment.
Enable Attribute Conformance: Ensure the option Conform attributes is checked.
Execute Update: Click Finish. The tool copies the library type and synchronizes all instances.
Recompile AS Charts: Perform a CFC Delta Compile (Changes only) on each AS.

SFC Type Synchronization Decision Matrix

The following table provides guidance based on discrepancy types discovered during SFC Type comparison:

Reported DiscrepancyNature of ChangeImpact on Running PlantRecommended ActionBT_ID mismatch onlyCompiler timestamp differenceZero impact; fully bumplessUpdate block types immediately; compile changesComment / Author changedMetadata text editZero impactUpdate block types; compile changesNew Setpoint parameter addedInterface expansionSafe if instances update cleanlyUpdate types; compile changes; download in RUNParameter deleted / retypedBreaking interface shiftMay cause instance DB resetSchedule during plant outage; requires full compileStep logic / Actions modifiedPhase execution changeAlters sequential control behaviorUpdate when phase is idle / between batch runs

Verification

Verify library alignment through the following steps:

Launch Options > Charts > Update Block Types again. Verify that all SFC Types indicate green checkmarks with zero differences.
In SIMATIC Manager, check the compile log under Options > Logs > Compile. Confirm 0 errors and 0 warnings.
In CFC, open an SFC Type instance in online Test Mode; verify that phase states, setpoints, and feedback operate normally.
In SIMATIC BATCH BatchCC, execute an equipment phase verification; confirm that all phase types validate successfully.

Limitations and Operational Precautions

Consider these operational rules when managing SFC Types:

Never Edit SFC Types Directly Inside Local AS Projects: Always modify the SFC Type in the Master Data Library and propagate outward; modifying local copies directly fractures library consistency.
SIMATIC BATCH Coordination: In facilities using SIMATIC BATCH, always update the process cell in BatchCC after synchronizing SFC Types to ensure recipe headers match controller phase types.
Multi-User Lock Checking: Ensure no other engineer has the target SFC Types open in another workstation before updating.

Engineer FAQ

Where should SFC Types be created: in the AS or in the Master Data Library?

Always create and modify SFC Types in the Master Data Library, then distribute them to the AS stations via the Update Block Types wizard.

How does an SFC Type update affect SIMATIC BATCH recipes?

If only BT_ID changed, recipes are unaffected. If phase control strategies or setpoints changed, you must run 'Update Process Cell' in BatchCC to update master recipes.