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FANUC Controller
Program/G-code · Intermediate · 5-30 minutes
Fanuc 103 - Illegal variable type
Alarm 103 ILLEGAL VARIABLE TYPE occurs when the control encounters a macro variable operation that attempts to use an incompatible data type or incorrect variable format. This typically happens when mixing system variables with local variables incorrectly, using undefined variable types, or attempting operations between incompatible variable classes in custom macros or PMC ladder programs.
103
Fanuc 103 - Illegal variable type
ILLEGAL VARIABLE TYPE
Fanuc PS program alarm 103: ILLEGAL VARIABLE TYPE. This alarm is triggered by an illegal or incorrectly formatted command in the part program, or a programming condition that the Fanuc control cannot execute.
Root Cause Summary
Alarm 103 ILLEGAL VARIABLE TYPE occurs when the control encounters a macro variable operation that attempts to use an incompatible data type or incorrect variable format. This typically happens when mixing system variables with local variables incorrectly, using undefined variable types, or attempting operations between incompatible variable classes in custom macros or PMC ladder programs.
Safety
- Verify corrected program or parameters before resuming machining
Causes and Fixes
- 1
Press ALARM button and note the exact program line number (N-number or sequence) where the alarm occurred.
- 2
Access the program in EDIT mode and locate the macro variable statement at the alarm line. Check for mixed variable types (e.g., #100=#3000 or similar assignments between local and system variables).
- 3
Verify the variable ranges: #1-33 (local), #100-199/#500-999 (common), #1000-1135 (system). Ensure operations stay within compatible variable classes and use intermediate variables if needed.
- 4
Correct the variable assignment by using proper syntax (e.g., #100=#3000 should be #100=[#3000] if reading system variable) or rewrite logic to use compatible variable types. Reset alarm and test program.
Always backup program before making changes. Test in single block mode first.
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Seeing another alarm with this one? Enter the code.
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