SRVO-050: Collision Detect alarm
The servo software estimated a disturbance torque too large to be normal motion and concluded the robot hit something.
What it means
The servo software estimated a disturbance torque too large to be normal motion and concluded the robot hit something. Sometimes it did. The rest of the time it's fighting bad payload data, cold grease, a dragging brake, or worn mechanics. The most-searched FANUC alarm for good reason.
Common causes
Ranked by what technicians most often find, most likely first.
- Actual collision or external force - including tool stuck to the work ('tip stick').
- Wrong payload settings (mass, center of gravity, inertia) - the most common false trigger.
- Aggressive motion: ACC over 100, sharp CNT reversals, linear moves near singularity.
- Cold plant, stiff grease - friction spikes after weekends and cold nights.
- Brake dragging or low supply voltage.
- Mechanical wear: reducer, balancer (listen for noise), or deeper hardware faults.
How to fix it
- Inspect for a real collision first. To recover: hold SHIFT+RESET, release only RESET, keep SHIFT held and jog the axis AWAY from the obstruction.
- Verify the payload schedule matches the actual tool and part; run payload ID if available.
- If tied to one aggressive move, soften it (reduce ACC, smooth the reversal, reroute from singularity). The disturbance threshold is visible at STATUS > Axis > DISTURB - resist the urge to raise it to silence the alarm; that removes a protection layer.
- After cold or idle periods, warm the robot at low speed before full-rate production.
- One axis triggering repeatedly with clean payload data earns a mechanical inspection: brake release, reducer, balancer.