Testing and Replacing Instantiated SIMIT Simulation Macros Across Multi-Diagram Projects

In SIMIT Simulation Platform (V10.1 and newer), instantiated macros in simulation diagrams are intentionally decoupled from library macro modifications to protect running simulation models. Saving a modified macro in the Macro Editor generates a new Unique Identifier (UID). To replace all legacy instances across project diagrams with the updated version, open the 'Find & Replace' (Suchen & Ersetzen) window, select the 'Replace' tab, activate the 'Update' (Aktualisieren) checkbox, search for the macro name, and click 'Replace All'. To test a macro standalone, instantiate it inside an isolated scratch simulation diagram connected to temporary slider and display controls.

Executive Summary

In simulation projects modeled with Siemens SIMIT (e.g., SIMIT V10.1 Upd 2 paired with SIMIT UNIT PN 128 simulating distributed I/O for an S7-414F controller), simulation engineers assemble reusable logic blocks called Macros (e.g., valve feedback simulators, motor thermal curves, conveyor positioners). When an engineer opens a macro in the SIMIT Macro Editor, makes enhancements, and saves it, they discover that existing macro instances already placed across dozens of project diagrams do not automatically reflect the changes. This behavior is by design: SIMIT enforces strict versioning using UIDs to prevent unintentional alteration of validated simulation behavior. Updating instantiated macros requires using SIMIT's targeted Find & Replace update mechanism.

Architecture and Fundamental Mechanics

The architecture of SIMIT Macro versioning and component replacement relies on explicit UID identification:

1. Macro UID Generation Mechanics

Every macro defined in the SIMIT project component library possesses a metadata header containing a Unique Identifier (UID):
- When a macro is dragged from the library into a simulation diagram, SIMIT creates an instance referencing the specific UID.
- When an engineer edits that macro in the Macro Editor and saves it, SIMIT does not overwrite the old type in-place; it generates a new UID representing the modified macro version.
- Existing diagram instances continue pointing to the legacy UID. This ensures that opening and editing a macro cannot corrupt or desynchronize an active multi-diagram simulation model.

2. The 'Update' Mode in Find & Replace

SIMIT provides a specialized engine within the Find & Replace utility designed specifically for macro version propagation:
- Standard Replace allows substituting any component type for another.
- Enabling the 'Update' (Aktualisieren) checkbox restricts substitution strictly to different versions of the identical macro type.
- The engine compares the old UID stored on the diagrams with the new UID generated in the library, highlighting version discrepancies and allowing one-click global synchronization.

Step-by-Step Implementation Procedure

To test and replace macros across a SIMIT V10.1 project:

Step 1: Standalone Testing of Modified Macro

In the SIMIT project tree, create an isolated test diagram named _Test_Macro.
Drag the newly saved macro from the project library onto the diagram.
Connect SIMIT standard controls: attach an analog slider or digital push-button to macro inputs, and attach numeric displays or chart recorders to macro outputs.
Start the SIMIT simulation (Simulation -> Start) and verify dynamic response, transfer functions, and boundary conditions.
Once validated, stop simulation and delete the temporary test diagram.

Step 2: Global Macro Replacement Across Project Diagrams

In the SIMIT main menu, select Edit -> Find & Replace (or press Ctrl+F).
Switch to the Replace (Ersetzen) tab.
Activate the checkbox 'Update' (Aktualisieren).
In the 'Find what' search box, enter the exact name of the modified macro.
Click Find (Suchen).
SIMIT displays a table listing every instance across all project diagrams, showing the legacy UID on the left and the new UID on the right.
Click Replace All (Alle ersetzen) to update all diagram instances to the new macro revision.

Step 3: Consistency Check and SIMIT UNIT Synchronization

Execute a project consistency check in SIMIT to ensure all input/output signal links remain intact.
If coupled to a physical hardware simulator like SIMIT UNIT PN 128, re-synchronize the I/O mapping table.
Save the project.

Verification

To confirm successful macro update:

Diagram Inspection:
- Open several simulation diagrams containing the macro.
- Open the properties of an instantiated macro and verify that its UID matches the new library version UID.
Simulation Runtime Test:
- Start the simulation with the S7-414F PLC online.
- Verify that simulated device behaviors (e.g., valve travel times, limit switch assertions) execute according to the updated macro logic.

Limitations and Operational Precautions

Operational limitations and precautions:

Interface Alterations: If the macro update added or removed connection pins (inputs/outputs), global replacement leaves new pins unconnected or severs deleted connections. Manual wiring inspection is required for altered interfaces.
Simulation Must Be Stopped: Macro replacement cannot be executed while the SIMIT simulation engine is in RUN mode.
Library Scope: Project-specific macros reside in the project library; global macros stored in the SIMIT installation library must be copied to project libraries before editing.
Commercial Disclaimer: Verify all SIMIT platform editions, SIMIT UNIT hardware, and expansion licenses with an authorized Siemens distributor or the Siemens Industry Mall.

Engineer FAQ

Why don't instantiated macros update automatically when edited in SIMIT?

SIMIT assigns a new UID to modified macros to protect existing simulation models from unintended behavioral changes. Updating instances requires an explicit Find & Replace action.

What does the 'Update' checkbox do in SIMIT Find & Replace?

It restricts replacement strictly to different version UIDs of the same macro type, preventing accidental substitution of unrelated components.

Can I test a SIMIT macro without connecting to a real PLC or Virtual Controller?

Yes. Instantiate the macro in a standalone diagram and connect SIMIT standard controls (sliders, buttons, displays) to test its internal logic offline.