Updating SFC Types and Equipment Module Types (EMT) from Master Library to Project in PCS 7 V9.0

In SIMATIC PCS 7 V9.0, running 'Update Plant Types' updates Equipment Module Type (EMT) and Control Module Type (CMT) chart templates but does not automatically update SFC Type instances because SFC Types are compiled technological function blocks (FBs) governed by the S7 Program block catalog. To update an SFC Type modified in the Master Library across all project instances, engineers must first update the block type in the AS S7 Program via Options -> Block Types in the Master Library, or open the target AS chart folder and select Options -> Update SFC Type from Library. Once the block interface is updated, running 'Update Plant Types' synchronizes the surrounding EMT chart structure.

Decoupled Synchronization Architecture: EMT Charts vs SFC Type Blocks

In SIMATIC PCS 7 V9.0, process modularization follows ISA-88 hierarchy where Equipment Module Types (EMT) coordinate subordinate Control Module Types (CMT). Within an EMT chart, sequential state-machine logic (e.g. heating phases, dosing sequences, valve sequences) is encapsulated inside an SFC Type.

A frequent point of engineering confusion occurs during library maintenance: an engineer adds a new Control Module to an EMT and updates the state steps in the associated SFC Type inside the Master Library. When they execute Options -> Plant Types -> Update Plant Types..., the EMT chart reflects the new CM, but the internal SFC Type instances in the project remain frozen at their old revision!

Why 'Update Plant Types' Omits SFC Type Logic Updates

This behavior occurs because EMTs and SFC Types belong to two completely different architectural domains inside STEP 7:

EMT / CMT (Chart Hierarchy Domain):
- EMTs and CMTs are stored as Continuous Function Chart templates in the Master Library's Plant Types folder.
- The Update Plant Types utility parses chart structures, technological connections, and optional variants. It manages how blocks are connected together inside the chart.
SFC Type (Executable Block Domain):
- An SFC Type is not merely a chart drawing; when created, the SFC compiler compiles it into an executable S7 Function Block (e.g., FB1025) stored inside the S7 Program 'Blocks' folder.
- Because modifying an SFC Type can change its internal FB interface (adding inputs, changing static memory layouts), updating it in an active CPU requires an S7 block type update transaction (Options -> Block Types).
- The Update Plant Types tool intentionally does not perform automatic block type overwrites to prevent unintended CPU stop hazards on running controllers.

Comparison of Synchronization Workflows in SIMATIC PCS 7 V9.0

The following table compares the responsibilities and execution scopes of the two synchronization mechanisms:

Synchronization ToolTarget ObjectLocation in MenuAction PerformedCPU ImpactUpdate Plant Types (PlantTypes)EMT & CMT Chart TemplatesOptions -> Plant Types -> Update Plant Types...Propagates new blocks, interconnections, and variantsNon-destructive; delta download in RUNUpdate Block Types (BlockTypes)SFC Type & FB CodeMaster Lib: Options -> Block Types...Copies compiled FB/UDT code into target AS block foldersMay require delta or entire compileUpdate SFC Type from LibrarySFC Type DefinitionProject SFC Type: Options -> Update from LibraryPulls modified steps, transitions, and contactsRequires SFC chart re-compilationSynchronize Plant TypesComplete Project TreePlant View: Right-click Project -> SynchronizeAnalyzes discrepancies between library and projectDiagnostic overview only

Step-by-Step Procedure to Synchronize EMTs and SFC Types

Follow this sequential procedure to ensure that both EMT chart structures and SFC Type sequences update cleanly:

Compile and Save Modified SFC Type in Master Library:
- In the Master Library, open the SFC Type under the S7 Program 'SFC Types' folder.
- Make required modifications (add new block contacts, step actions, or transitions).
- Select SFC -> Save and SFC -> Compile. Ensure the SFC Type compiles with 0 errors, generating the updated FB.
Update Block Types in Target Automation Stations:
- In the Master Library S7 Program 'Blocks' folder, select menu Options -> Block Types....
- In the Block Types dialog, locate your SFC Type in the left pane.
- In the right pane, select the target S7 Program of your Automation Station (AS).
- Click the arrow button -> to execute Update Block Types.
- Confirm the update prompt. PCS 7 updates the FB definition and all instance DB interfaces across the project.
Synchronize EMT and CMT Chart Instances:
- In SIMATIC Manager, select menu Options -> Plant Types -> Update Plant Types....
- Select your updated Equipment Module Type (EMT).
- Click Next and execute the synchronization.
- This updates the chart layout, places new Control Modules, and binds connections to the updated SFC Type block.
Recompile Charts and SFCs:
- Open the CFC Editor and select Chart -> Compile -> Changes only.
- In the compilation dialog, select the checkbox for Compile SFCs.
- Execute a delta download (PLC -> Download -> Changes only) in CPU RUN mode.

Verification

Verify synchronization across all EMT instances:
1. Open a project EMT chart that was instantiated from the library.
2. Inspect the embedded SFC Type block instance: confirm that newly added block contacts, inputs, and step parameters appear on the block symbol.
3. Open the SFC Type instance faceplate view or SFC chart: verify that the newly authored sequence steps and transitions are visible.
4. Select Options -> Plant Types -> Synchronize Plant Types and verify that the status reports 100% synchronized with zero deviations.

Limitations and Operational Precautions

Interface Modification CPU STOP Risk: If an SFC Type interface alteration alters the length of static parameters or deletes active inputs while the controller is running, the compiler may refuse a delta download, requiring a CPU STOP to re-initialize instance DBs. Always test interface modifications on a simulated testbed first.
Active Step Execution: When downloading changes to an SFC Type in CPU RUN mode, ensure no physical batches or sequences are actively executing that specific phase, as step reallocation can cause unexpected transition resets.
Version Numbering: Always increment the version number of the SFC Type in Object Properties (e.g. from V1.0 to V1.1) prior to updating block types to maintain traceable audit history.

Engineer FAQ

Why did 'Update Plant Types' update my CMTs but not my SFC Type?

Update Plant Types manages chart layouts, block placements, and interconnections, but does not update compiled block code. Because SFC Types are compiled into executable Function Blocks (FBs), their interface must be updated via Options -> Block Types.

Can I update an SFC Type without stopping the S7-400 CPU?

Yes, provided the modification does not change existing parameter memory offsets in an incompatible manner. If only internal step logic, transition conditions, or new optional inputs are added, CFC can compile and download changes in CPU RUN mode.

What happens if I update the block type before updating the plant type?

Updating the block type first is the recommended sequence. It ensures that the underlying FB interface is present in the S7 Program before the EMT chart synchronizer attempts to bind connections to the newly added block pins.