This is a Fanuc alarm “hub” optimized for the way operators actually search: they see an alarm, copy the number/text, and Google it. Fanuc alarm numbering can vary by builder and series, so this page teaches a repeatable diagnosis workflow plus the most commonly searched Fanuc alarm families (P/S, overtravel, servo, APC, macro alarms) with real, shop-proven fixes.
TABLE OF CONTENTS
1) Fanuc alarm workflow (fast triage)
2) The “Big 7” Fanuc alarm families
3) Most Googled Fanuc alarm categories and why they happen
4) Macro alarms (#3000/#3006) and what pros do
5) Overtravel recovery without creating a crash
6) Prevention templates (state reset + safe Z strategy)
7) FAQ (what people search most)
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1) FANUC ALARM WORKFLOW (FAST TRIAGE)
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1) Record alarm number(s) + full text + block/sequence.
2) Identify what phase: rapid, cut, tool change, probing, homing, subprogram return.
3) Check modal state snapshot:
- G90/G91
- G20/G21
- G17/G18/G19
- G54–G59 (or extended offsets)
- Cutter comp state (G40/G41/G42)
- Tool length comp (G43 H#)
- Canned cycle active? (G80)
4) If motion-related: reduce rapid override, single-block, verify clearance before rerun.
5) Fix root cause (offset/mode/comp), not just the alarm.
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2) THE “BIG 7” FANUC ALARM FAMILIES
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A) Overtravel / stroke limit
B) Servo alarms / following error / overload
C) P/S program alarms (syntax / illegal command / missing feed)
D) APC / reference return alarms (absolute encoder / home)
E) Spindle / drive alarms
F) I/O / communication alarms
G) Macro / programmable alarms (#3000 / #3006)
These families are more useful than memorizing individual numbers.
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3) MOST GOOGLED FANUC ALARM CATEGORIES (REAL CAUSES)
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OVERTRAVEL / OT (+X/-Z etc.)
WHAT IT USUALLY MEANS:
The toolpath target is outside allowable travel, often due to offsets or mode.
MOST COMMON REAL CAUSES:
- Wrong work offset (G54 vs G55)
- Wrong sign on Z
- Accidental incremental mode (G91)
- Unsafe homing pattern or unsafe intermediate position
- Blind rapid down moves (G00 into negative Z)
FAST FIX:
- Verify you can jog off the limit safely.
- Confirm work offset values make physical sense.
- Re-run from a safe retract block, not the alarm line.
PREVENTION:
Always use a “Z-first” safe reposition policy: Z safe → XY → feed down.
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SERVO ALARM / FOLLOWING ERROR (commonly searched as “servo alarm 401/414/…”)
WHAT IT USUALLY MEANS:
The axis cannot follow commanded motion within tolerance.
MOST COMMON REAL CAUSES:
- Tiny CAM segments at high feed (controller constantly accel/decel)
- Too aggressive accel/jerk for heavy fixtures
- Mechanical binding (chips, lube failure, crash damage)
- Rotary axis clamp/unclamp timing issues (builder dependent)
FAST FIX:
- Reduce feed and rapid override and reproduce safely in the air.
- Inspect for mechanical obstruction and lubrication.
- If repeatable at one location: suspect mechanical “hard spot.”
PREVENTION:
- Use smoothing where appropriate and avoid ultra-dense segment output.
- Use constant-engagement roughing strategies to prevent torque spikes.
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P/S PROGRAM ALARMS (FORMAT / ILLEGAL COMMAND / NO FEED)
WHAT IT USUALLY MEANS:
The control rejected a block due to syntax, illegal state, or missing data.
COMMON TRIGGERS:
- Missing feedrate on first G01/G02/G03 after tool change
- Illegal modal group combination
- Arc definition wrong for the active plane
- Canned cycle missing required parameters
- Unsupported option code in the program
FAST FIX:
- Go to the reported block, check the modal state, and correct the syntax.
- Confirm plane vs arc I/J/K usage and that cycles are canceled properly.
PREVENTION:
Use a strict safe-start header and always set feedrate on the first cutting move of every operation.
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APC / ABSOLUTE ENCODER / REFERENCE RETURN (commonly “APC alarm 300” searches)
WHAT IT USUALLY MEANS:
The control lost absolute position reference, often battery-related or after moving axis with power off.
FAST FIX:
- Follow the machine builder’s procedure for restoring reference.
- Replace batteries safely and re-home properly.
- Verify reference repeatability before cutting.
PREVENTION:
Scheduled battery replacement and avoiding moving axes with power off.
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MACRO / PROGRAMMABLE ALARMS (#3000 and messages)
WHAT IT USUALLY MEANS:
A macro intentionally stopped the program due to a condition (tool life exceeded, probe failed, wrong offset active, etc.).
PRO TIP:
Search the program for #3000 or #3006 and read the message—this is usually a designed safety stop.
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4) WHAT PROS DO (THEIR DEFAULT PREVENTION STACK)
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- Safe start resets: absolute, plane, units, cancel comp, cancel cycles
- Safe retract policy: never XY rapid at low Z
- Strict tool mapping: T matches H (and D when used)
- Drilling discipline: cancel cycles with G80 immediately
- Transform discipline: cancel rotation/tilt before machine-coordinate moves
- First-run discipline: single block + reduced rapid + air cut above part
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5) FANUC-SAFE OVERTRAVEL RECOVERY (SHOP PRACTICE)
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1) Do not force movement blindly.
2) Jog off the limit at minimal speed.
3) Verify offsets and mode (G90/G91) before rerunning.
4) Rerun from a known safe retract line.
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6) PREVENTION TEMPLATES (STRUCTURE, NOT BRAND-SPECIFIC)
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SAFE START (CONCEPT):
- Set units
- Set plane
- Set absolute
- Cancel cutter comp / length comp / cycles
- Select WCS
- Retract to safe Z before any XY move
SAFE END (CONCEPT):
- Cancel cycles/comp
- Retract to safe Z
- Stop spindle/coolant
- Park if required
- End program
This page is designed to be the “first click” when operators search Fanuc alarms, then guide them to the correct fix path quickly.
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