What the SRVO-023 alarm means

While the axis was supposed to hold position, the position error exceeded the limit - the axis drifted or was pushed away from its commanded position. We have built up many handled cases of this FANUC R-30iA / R-30iB / R-30iB Plus alarm, and usually the first on-site inspection tells us what is wrong.

Most common causes

  • Brake failure or worn brake (gravity sag on J2/J3 is classic)
  • External force or collision while stopped
  • Mechanical binding or excessive friction
  • Wrong payload setting
Field note: Confirm or rule out the first cause first — it is the situation we encounter most.

Step-by-step field fix

  1. Check if the axis sags when servo is off - if yes, suspect the brake
  2. Verify payload/arm load settings are correct
  3. Inspect gearbox and bearings for binding
  4. Push-test the axis by hand with brake released to feel for abnormal resistance
Safety first: For FANUC srvo-023, servo circuits are live and motor shafts and reducers rotate: measuring current waveforms or winding resistance means contact with live or moving parts. On site you may look at after confirming power-off the first step yourself: Check if the axis sags when servo is off - if yes, suspect the brake. Beyond that it is live servo circuits and rotating parts work - leave it to a professional.

How we diagnose servo alarms on site

FANUC srvo-023 belongs to the servo & drive family. On FANUC srvo-023 the failing stage is alpha-i / beta-i servo amplifiers with PSM supply modules and SVM servo modules (SPM where spindles fit) on the R-30iB Plus / R-30iB Mate Plus / R-30iA - the servo closed loop: current/velocity/position loop misbehaviour, motor-drive matching and load identification. We start reading FANUC srvo-023 at the iPendant ALARM screen (SRVO / MOTN / SYST / INTF prefixes) together with the amplifier's 7-segment status code.

The chain involved in FANUC srvo-023 runs: target -> position loop -> velocity loop -> current loop -> power output -> motor -> feedback -> loop compare.

FANUC srvo-023 can be a parameter problem, not hardware: Some servo alarms are parameters, not hardware: after a fixture change the load moved but gains and load identification were never redone, loop response degraded, and high speed or hard stops now raise following error or oscillation. The fix is updating tooling weight and centre-of-gravity data, re-running load identification and trimming gains to the real takt. No spares at all - but no drive swap will fix it either if the parameters stay stale.

Field notes on this page cover FANUC srvo-023 (Stop Error Excess (Group / Axis)); written by the Henghuan repair team, updated 2026-10-01.

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Related Servo & Drive alarms

SRVO-021 — SRDY Off (Group / Axis) SRVO-024 — Move Error Excess (Group / Axis) SRVO-043 — DCAL Alarm - Discharge Alarm SRVO-044 — HVAL Alarm - High Voltage SRVO-045 — HCAL Alarm - High Current SRVO-046 — OVC Alarm - Overcurrent (Average)
Same family: this code belongs to the Servo & drive alarms family - the page collects all Servo & drive-family codes we have handled, with the common inspection order and spares.
Other brands: see our KUKA, ABB, Yaskawa and Universal Robots field-fix libraries — or the full 10-brand hub.

Frequently asked questions

QWhat does the FANUC srvo-023 alarm mean?

While the axis was supposed to hold position, the position error exceeded the limit - the axis drifted or was pushed away from its commanded position. We have built up many handled cases of this FANUC R-30iA / R-30iB / R-30iB Plus alarm, and usually the first on-site inspection tells us what is wrong. FANUC srvo-023 sits in the servo & drive family; on our work orders the highest-frequency trigger for this code is "Brake failure or worn brake (gravity sag on J2/J3 is classic)".

QCan I clear a FANUC srvo-023 alarm myself?

Whether FANUC srvo-023 clears on its own depends on the outcome of "Check if the axis sags when servo is off - if yes, suspect the brake". Finish the flow with "Push-test the axis by hand with brake released to feel for abnormal resistance" to confirm FANUC srvo-023 - do not skip it. If that step is clean, the second most frequent cause on FANUC srvo-023 is "External force or collision while stopped". Two attempts and still there means stop: FANUC srvo-023 involves live servo circuits and rotating parts, and running FANUC srvo-023 on can turn a repairable fault into a replacement.

QFor servo alarms like FANUC srvo-023, how do you tell motor from drive?

The commonest causes we see on FANUC srvo-023 are "Brake failure or worn brake (gravity sag on J2/J3 is classic), External force or collision while stopped, Mechanical binding or excessive friction", so we stock the van against those. For FANUC srvo-023 specifically, we bring the scope and meter; motors and drives are stocked by type, and most cases are measured before parts are ordered. For FANUC srvo-023, on servo alarms we specifically avoid misjudgement: waveform first, parts second, so customers skip needless swaps. Before we roll, tell us what FANUC srvo-023 shows on the iPendant ALARM screen (SRVO / MOTN / SYST / INTF prefixes) together with the amplifier's 7-segment status code and what the machine was doing - phone or video triage is free.

The notes on FANUC srvo-023 were summarized by the Henghuan Robotics repair team from on-site service. The alarm interpretation is our empirical summary for troubleshooting reference and may vary by controller and software version — please check FANUC documentation or contact us with questions. Henghuan is an independent service provider, not affiliated with or endorsed by FANUC.