Synchronizing Control Module Types (CMT) with Project CFC Charts in SIMATIC PCS 7

In SIMATIC PCS 7 (v8.0, v8.1, v8.2, and v9.0), when a Control Module Type (CMT / Einzelsteuereinheitstyp) is modified in the Master Data Library (such as adding an auxiliary function block, inserting an interlock parameter, or modifying message attributes), updating and synchronizing all instantiated CFC charts (Control Modules) across the Multiproject is performed using the 'Synchronize Plant Types' function. In SIMATIC Manager, select the Master Data Library or AS project, choose 'Options > Plant Types > Synchronize...', review the comparison tree highlighting structural differences between library templates and project instances, and click 'Synchronize'. This automated process propagates all structural additions while preserving instance-specific parameter values, setpoints, and I/O assignments.

Architecture of Control Module Types (CMT) vs Classic Process Tag Types

In SIMATIC PCS 7 engineering, standardizing repetitive technological units is essential for maintaining software quality and reducing engineering costs. In legacy PCS 7 versions (v7.1 and earlier), this was accomplished using Process Tag Types (PTT) and the Import/Export Assistant (IEA).

Starting with PCS 7 V8.0, Siemens introduced Control Module Technology (CMT). Control Module Types provide fundamental architectural enhancements over legacy PTTs:
- Object-Oriented Type-Instance Architecture: A CMT in the Master Data Library acts as an authoritative type definition. Changes made to the type can be audited, compared, and synchronized with existing instances (Control Modules) at any point in the plant lifecycle.
- Optional Blocks and Variants: A single CMT can contain optional sub-control modules (e.g., an optional vibration transmitter, optional feedback channel, or alternative interlock logic) that can be activated or deactivated on individual instances without breaking type inheritance.
- Bidirectional Comparison: The engineering system can compare an instance against its library type, highlighting unauthorized manual changes made in the field.

Mechanism of Type-Instance Synchronization (Typabgleich)

When an automation engineer modifies a CMT in the Master Data Library—such as:
- Inserting a new block (e.g., adding an interlock block Intlk02)
- Connecting a new internal signal line
- Adding an exposed block parameter or message attribute
- Modifying block type versions (e.g., upgrading from APL V8.1 to V8.2)

The existing CFC charts in the AS projects do not update automatically in real time. This deliberate design prevents unexpected changes from breaking online controllers.

To propagate changes safely, PCS 7 utilizes the Type-Instance Synchronization Tool (Typabgleich). The synchronization engine parses the library CMT template and scans every instantiated Control Module across all AS projects in the Multiproject, compiling a comprehensive structural delta tree.

Step-by-Step CMT Synchronization Procedure

To synchronize modified Control Module Types with project CFC charts:

Step 1: Modify and Validate the CMT in the Master Data Library

In SIMATIC Manager, open the Master Data Library.
Navigate to the Plant Hierarchy folder or Templates directory containing the Control Module Types.
Open the CMT in the CFC editor and implement the required engineering changes (e.g., add parameter, insert block).
Save and close the CMT editor.

Step 2: Launch the Synchronization Tool

In SIMATIC Manager, select the Master Data Library root or the target Multiproject.
Select menu Options > Plant Types > Synchronize... (or right-click the specific CMT in the library and select Plant Types > Synchronize...).

Step 3: Analyze the Comparison Tree

The Type-Instance Synchronization Dialog opens, displaying a split-pane comparison:
1. Left Pane (Library Types): Lists all CMTs and their modified elements.
2. Right Pane (Project Instances): Displays all instantiated Control Modules across all AS stations.
3. Observe status color codes:
- Green: Instance is fully synchronized with the library type.
- Yellow / Blue: Instance has structural differences (new blocks, removed blocks, or updated parameters available).
- Red / Conflict: An instance has a local manual conflict that cannot be resolved automatically without user confirmation.

Step 4: Execute Synchronization

Select the checkboxes for the Control Module Types you intend to update.
Click Synchronize (or Abgleichen).
The system processes all CFC charts in batch mode, inserting new blocks, updating interconnections, and synchronizing block attributes.
When finished, a confirmation log details all updated instances with zero compilation errors.

Preservation of Instance-Specific Data During Updates

A major concern for plant engineers is whether updating a CMT will overwrite field-configured values.

The CMT synchronization engine adheres to strict rules of data preservation:
1. Preserved Parameters:
- Physical I/O symbolic interconnections (e.g., peripheral inputs mapped to Pcs7DiIn.PV_In).
- User-adjusted operational parameters (e.g., configured alarm limits HighLimit, setpoint limits, operational timers).
- Instance tag names, chart comments, and Plant Hierarchy positions.
2. Propagated Changes:
- New function blocks added to the CMT.
- Internal block-to-block interconnections defined at the type level.
- New block parameters exposed for visualization or OS compilation (s7_m_c).
- Updated message texts and message classes defined in the template.

CMT Synchronization Parameter and Action Matrix

The following matrix details how different CMT modifications impact project instances during synchronization:

Modification Made to Library CMTSynchronization Behavior on InstancesImpact on Instance-Specific DataAS Download Requirement Following SyncNew Block Added to CMTBlock inserted into all instance CFCs with matching run sequenceInstance parameters untouched; new block takes default valuesDelta download in RUN permittedNew Internal InterconnectionSignal line created between blocks in all instancesExisting external I/O links preservedDelta download in RUN permittedNew Exposed ParameterParameter exposed for OS compile or interlockParameter initialized to type defaultDelta download in RUN + Changes OS compileDeleted Block from CMTBlock removed from all instancesDeletes internal connections belonging to removed blockDelta download in RUN permittedBlock Type Library UpgradeBlock types updated to new library revisionAll instance block headers updatedPotential CPU STOP if structural DB changed

Verification

To confirm that Control Module Types are successfully synchronized across the project:
1. In SIMATIC Manager, re-open Options > Plant Types > Synchronize....
2. Verify that all instances in the comparison tree show status Synchronized (Green checkmark).
3. Open a sample instantiated CFC chart in the project: Confirm that the newly added blocks and internal connections appear in the chart.
4. Check instance parameters: Verify that physical I/O addresses and custom alarm limits were preserved intact.
5. In SIMATIC Manager, execute Compile Charts as Program with 'Changes only'. The compilation must complete with 0 Errors.
6. Perform a Download Changes to the AS controller: Confirm that the controller accepts the delta download in RUN mode.

Limitations and Operational Precautions

Observe the following engineering precautions:
- Do Not Modify CFC Instances Manually: Avoid manually adding blocks or deleting signals directly inside instantiated Control Module CFCs. Local manual edits create synchronization conflicts (marked yellow/red) that complicate future batch library updates.
- Advanced ES License Prerequisite: Configuring and synchronizing Control Module Types requires the PCS 7 Advanced ES software license on the Engineering Station.
- Official Documentation Reference: Detailed workflows and application examples are documented in Siemens Application Example Entry ID 109475748 ('Control Module (CM) Technology - Efficient Engineering with SIMATIC PCS 7').

Engineer FAQ

Where is the official documentation for CMT synchronization located?

Siemens details CMT workflows in the official application example 'Control Module (CM) Technology - Efficient Engineering with SIMATIC PCS 7' (Siemens Industry Online Support Entry ID 109475748) and in the PCS 7 Engineering System manual.

Will synchronizing a CMT overwrite my field transmitter scale settings?

No. The synchronization engine strictly protects instance-specific parameter values. Configured scale limits, setpoints, and I/O addresses remain untouched while structural additions are applied.

Can I synchronize CMT changes while the plant is running?

Yes, in most cases adding blocks or parameters to a CMT results in changes that support delta compilation and delta download to the AS controller in RUN mode without process interruption.