What causes FANUC alarm 112?

Machine system or function indicated by the alarm name has detected a fault. Control parameter or configuration error related to the alarm condition. Hardware component fault on the CNC or machine. Part program error or illegal operation for the indicated function. Machine interlock or safety condition not satisfied.

How do I fix FANUC alarm 112?

1. Note the alarm number and check the Fanuc alarm screen for any sub-code or additional details. 2. Identify the specific machine system or function from the alarm name. 3. Power cycle the machine to clear transient faults. 4. Consult the Fanuc parameter or operator manual for alarm 112 specific remedy. 5. Contact Fanuc service if the alarm persists after basic troubleshooting.

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FANUC Controller

Program/G-code · Basic · 10-20 minutes

Alarm 112

Fanuc Alarm 112 - Unknown Format

Fanuc Alarm 112 occurs when the CNC control detects a program file or data block that does not conform to either ISO (G-code) or EIA (older tape format) standards. This is typically caused by incorrect program formatting, unsupported characters, missing or corrupted program headers, or file transfer encoding errors that introduce invalid control characters.

FANUCProgram/G-codeBasic10-20 minutes

112

Fanuc Alarm 112 - Unknown Format

Not ISO/EIA

Root Cause Summary

Fanuc Alarm 112 occurs when the CNC control detects a program file or data block that does not conform to either ISO (G-code) or EIA (older tape format) standards. This is typically caused by incorrect program formatting, unsupported characters, missing or corrupted program headers, or file transfer encoding errors that introduce invalid control characters.

Safety

Cannot read program

Causes and Fixes

1
Check program header structure: ISO programs must start with '%' on first line, followed by 'O' number (e.g., O1234), and end with '%'. EIA programs use ER (End of Record) and LF (Line Feed) codes.
2
Navigate to EDIT mode, select the program in question, and verify the first and last lines display correctly. If garbled characters appear, the file is corrupted.
3
Check Parameter 3107 (ISO/EIA code setting). Bit 0: 0=ISO, 1=EIA. Verify this matches your program format. Access via SYSTEM > PARAM > search [3107].
Changing parameter 3107 requires parameter write enable (PWE=1) and may affect all program interpretation.
4
Re-send the program using DNC or storage device with verified file format. Ensure text editor saves as plain ASCII without BOM (Byte Order Mark) or special encoding.

DIY Feasiblehigh confidence

Call a technician if:

·Parameter corruption suspected
·Alarm persists after program corrections
·Communication hardware failure

Prevention

Always use ASCII text format for programs
Verify communication settings before DNC transfer
Use proper program structure with % delimiters
Test programs in single block mode after transfer

Common Mistakes

Using Unicode text editors
Copying programs from email or web browsers
Incorrect RS-232 parameter settings
Missing program start/end % characters

Related Alarms

010 078 113

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