Common Cicode Errors and How to Fix Them in AVEVA™ Plant SCADA

Avoid downtime with this complete guide to common Cicode errors in AVEVA™ Plant SCADA. Learn causes, solutions, and debugging tips with real examples.

Cicode is the scripting language that powers advanced automation and custom logic in AVEVA™ Plant SCADA (formerly CitectSCADA).

While Plant SCADA provides a graphical configuration environment, Cicode is essential for:

Event-driven logic (e.g., start/stop sequences)
Advanced calculations
Custom alarm handling
Integrations with external systems

However, even experienced engineers make mistakes in Cicode that can cause runtime errors, unexpected behavior, or degraded performance. In this guide, we’ll cover the most common Cicode errors, how to fix them, and best practices to avoid them in future — complete with real-world examples.

1. Syntax Errors

What it looks like: “Syntax Error” or red highlight in the editor.

Common causes:

Missing semicolons
Mismatched brackets
Misspelled keywords

Faulty Code:

INT iCount
iCount = 10
IF iCount > 5 THEN
    Message("Info", "Count is greater than 5")
END

Corrected Code:

INT iCount;
iCount = 10;
IF iCount > 5 THEN
    Message("Info", "Count is greater than 5");
END

2. Undefined Variables

Error: Variable ‘PumpStatus’ is undefined

Cause: Used without declaration or declared in a wrong scope.

Faulty Code:

IF PumpStatus = 1 THEN
    StartPump();
END

Corrected Code:

INT PumpStatus;
PumpStatus = TagRead("Plant1.Pump101.Status");

IF PumpStatus = 1 THEN
    StartPump();
END

3. Incorrect Tag References

Issue: TagRead() returns zero or wrong value.

Faulty Code:

Level = TagRead("Tank1_Lvl");

Corrected Code:

Level = TagRead("Plant1.Tank1.Level");

4. Infinite Loops

Symptom: System freezes, CPU 100%

Faulty Code:

WHILE TRUE DO
    TagWrite("Pump101.Status", 1);
END

Corrected Code:

WHILE TagRead("Pump101.Enable") = 1 DO
    TagWrite("Pump101.Status", 1);
    SleepMS(1000);
END

5. Overusing Sleep/Delay

Impact: Laggy system response

Sleep(10);

Tip: Replace with event-driven methods like EventSet()

6. Runtime Null Errors

Example: Reading from offline device

IF TagRead("Plant1.FlowSensor1.Status") = 1 THEN
    FlowRate = TagRead("Plant1.FlowSensor1.Rate");
ELSE
    FlowRate = 0;
END

7. Not Freeing Resources

Cause: Opened files not closed

Corrected Code:

INT hFile = FileOpen("log.txt", "a");
FileWrite(hFile, "Data line");
FileClose(hFile);

Best Practices to Avoid Errors

Use modular functions
Stick to tag naming standards
Comment code often
Test in simulation before going live
Reuse common code blocks from a library

Debugging Tips

Use Message() and Trace() for diagnostics
Check the Kernel window for logs
Use breakpoints for line-by-line debugging

Need help with Cicode optimization or advanced AVEVA™ Plant SCADA training?

Contact our team for expert assistance.

Common Cicode Errors and How to Fix Them in AVEVA™ Plant SCADA