AI-assisted Structured Text generation directly from the TwinCAT engineering shell.

2. 🟡 HIGH: SR_LineController Declaration Section is a God Object

Problem: SR_LineController's declaration section contains ~80+ local variables spanning safety, alarming, format change, machine mode, transport mode, controller, machine signals, motion, light grid, IPC, and more. This is a flat, unstructured declaration that mixes concerns.

Recommendation: Group related variables into local structs:

VAR
    stSafety   : ST_LineController_Safety;
    stAlarming : ST_LineController_Alarming;
    stFormat   : ST_LineController_FormatChange;
    stMode     : ST_LineController_MachineMode;
    ...
END_VAR

This improves readability and makes it easier to refactor sub-functionality into separate function blocks later.

3. 🟡 HIGH: NWL (Ladder/Function Block Diagram) Actions Should Be Converted to ST

Problem: Many SR_LineController actions are implemented in NWL (Network/Ladder) format — InputProcessing_active, ControllerLogic_active, OperationMode_active, ServiceMode_active, OutputProcessing_active, etc. This is:

• Harder to version-control (XML serialization of graphical elements)
• Harder to review in code diffs
• Slower to edit programmatically

Recommendation: Convert all NWL actions to Structured Text (ST). For example, ControllerLogic_active (3 AND gates with latches) is trivial in ST:

xModeReady    := xActOperation OR xActService;
xActOperation := xInputOperation AND xModeReady;
xActService   := xInputService AND xModeReady;

4. 🟡 MEDIUM: Format Change Logic is Fragile

Problem: The format change detection in GlobalServices_active compares 8+ hardware cam data values against stored "temp" variables. This is:

• Hardcoded — adding a new cam axis means adding another OR condition and another temp variable
• Brittle — the comparison uses <> which fails on REAL precision issues
• Incomplete — only checks filling needle and pre-seal placement, but not rotor centring, outlet, or sealing axes

Recommendation: Create a dedicated FB_FormatChange function block:

FUNCTION_BLOCK FB_FormatChange
VAR_INPUT
    i_astCamData : ARRAY [*] OF ST_CamSnapshot;
END_VAR
VAR_OUTPUT
    q_xFormatChanged : BOOL;
END_VAR

With a method to register cam data sources and compare with configurable tolerance.

5. 🟡 MEDIUM: Missing Sealing Equipment Module

Problem: The project has EM_01 (Global), EM_02 (Transport), EM_03 (Filling), EM_04 (PreSealing) — but no EM for final sealing/crimping. The SR_LineController declaration has temp variables for rSealCrimpingStartPositionTemp and rSealCrimpingCrimpPositionTemp that are declared but never used in the format change logic (commented out or missing). This suggests sealing was planned but not yet implemented.

Recommendation: Either implement EM_FinalSealing or remove the unused variables to avoid confusion.

6. 🟡 MEDIUM: Persistent Data Strategy

Problem: Only stRuntime and stController are PERSISTENT. The AxisRestoreStore GVL (RETAIN PERSISTENT) stores axis restore positions separately. This split means:

• If the PLC is cold-started, axis restore positions are lost (RETAIN only)
• The relationship between stRuntime and axis positions is unclear

Recommendation: Move axis restore positions into stRuntime as a nested struct, or at minimum document the persistence strategy clearly.

7. 🟢 LOW: Machine Configuration is Hardcoded

Problem: In OutputProcessing_active, EXUNIT.FC_LineConfiguration is called with hardcoded literals:

i_uiMachineType := 50;
i_xVials := TRUE;
i_xInletTurntable := TRUE;
i_uiObjectsPerHolderMax := 6;
i_uiObjectsPerHolderMin := 3;
...

Recommendation: Move these to a configuration GVL or the ST_LineConfig struct so they can be changed without modifying the program code.

8. 🟢 LOW: Error Quit Logic is Scattered

Problem: Error quit processing happens in:

• InputProcessing_active (TP + R_TRIG for the button)
• GlobalServices_active (output forwarding logic)
• ModuleDispatch_active (forwarded to each EM)

The TON_VendorErrorQuit and TP_VendorErrorQuit in SR_LineController suggest a vendor-specific workaround that's mixed with the main logic.

Recommendation: Encapsulate all error quit handling into a single FB_ErrorQuit function block with configurable pulse timing and vendor-specific extensions.

9. 🟢 LOW: IPC Correction Array Update is Inefficient

Problem: In GlobalServices_active:

FOR i:= 1 TO EXUNIT.LineConfig.g_c_uiStandardObjectCount DO
    stController.arProcessCorrection[i] := stRuntime.stTransport.stRotor.stVal.astNetWeightIpc[i].rCorrection;
END_FOR

This copies the entire array every cycle, even when nothing changed.

Recommendation: Use MEMCPY (from Tc2_Utilities) or only update on change detection.

10. 🟢 LOW: No Unit Testing / Simulation Harness

Problem: The project has no test infrastructure. With 226 files and complex SFC state machines, manual testing is the only option.

Recommendation: Consider adding:

• A SR_TestSimulation program that can inject test values into stHardware inputs
• A test sequence SFC that exercises each machine mode
• TcUnit or a custom test framework

Summary Priority Matrix

Would you like me to implement any of these changes? I'd recommend starting with #1 (drive reset duplication) and #4 (format change FB) as they provide immediate maintainability benefits with low risk.