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FANUC Controller
Program/G-code · Intermediate · 20-45 minutes
Fanuc Alarm 113 - IMPROPER COMMAND
Fanuc Alarm 113 occurs when a G-code or M-code function that is prohibited within a custom macro (user macro or macro executor program) is commanded. This typically happens when attempting to use external I/O instructions, certain program control commands, or machine-specific functions inside macro variables O9000-O9999 series programs that are restricted by the CNC system architecture.
113
Fanuc Alarm 113 - IMPROPER COMMAND
Zero Division
Fanuc alarm 113: Zero Division. This alarm indicates a fault condition detected by the Fanuc control. Refer to the alarm number and name to identify the specific system or function involved.
Root Cause Summary
Fanuc Alarm 113 occurs when a G-code or M-code function that is prohibited within a custom macro (user macro or macro executor program) is commanded. This typically happens when attempting to use external I/O instructions, certain program control commands, or machine-specific functions inside macro variables O9000-O9999 series programs that are restricted by the CNC system architecture.
Safety
- Program execution will halt - ensure workpiece and tooling are secure before restart
- Incorrect program logic leading to a zero division error can cause unexpected machine behavior. Ensure the machine is in a safe state before running or debugging the program.
- Be aware of rapid machine movements during program execution. Keep a safe distance from moving parts.
- If the error occurs during automatic operation, be prepared to activate the emergency stop if necessary.
- Modifying machine parameters or programs should only be done by qualified personnel.
Causes and Fixes
- 1
Identify the exact line number in the custom macro program (O9xxx series) where alarm triggered by reviewing alarm history screen (ALARM > HISTORY) to see NC program name and sequence number.
- 2
Check if G04 (dwell), G10 (programmable data setting), G65/G66/G67 (macro call nesting beyond 4 levels), or external device commands (DPRNT, POPEN) are used in the macro program at the flagged line.
- 3
Verify parameter 6071 (macro call nesting level) and parameter 6005 bit settings which control allowable macro functions - access via SYSTEM > PARAM > search 6005 or 6071.
- 4
Remove or relocate the prohibited command outside the macro body into the main program, or replace with macro-compatible alternatives (use #3003 timer instead of multiple G04, use SETVN instead of G10 where applicable).
Call a technician if:
- ·Complex nested macro programs with multiple subroutines
- ·Alarm persists after variable initialization fixes
- ·System parameters related to macro execution need modification
Prevention
- Always initialize macro variables before use
- Implement input validation for all divisor variables
- Use conditional logic to check for zero values before division
- Enable macro variable monitoring during program development
Common Mistakes
- Assuming variables retain values between program cycles
- Not checking calculation results before using as divisors
- Using uninitialized local variables in subroutines
- Forgetting that empty variables evaluate to zero in mathematical operations
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