What the BrakeFault alarm means

An axis falls when power is removed, or the brake release command does not free the axis; brake behavior is inconsistent between axes. Our engineers run into this alarm every week on Staubli CS8 / CS9 (VAL3) controllers, and a single on-site inspection usually identifies the problem.

Most common causes

  • Brake coil open or shorted
  • 24 V brake supply wiring fault
  • Mechanically seized brake
  • Wrong brake type fitted after a motor swap
Field note: In our repair stats the first cause has the highest hit rate, so confirm it first before digging further.

Step-by-step field fix

  1. Measure the brake coil resistance
  2. Check the 24 V at the brake connector during release
  3. Support the arm, then test brake release manually
  4. Inspect for corrosion or contamination in the brake
  5. Replace the brake/motor assembly if the brake is seized
Safety first: For Staubli brakefault, a failed brake means a vertical axis can drop - a person underneath is a severe-accident case, so we require mechanical support first and no repeated power-on trials. On site you may not carry out the first step yourself: Measure the brake coil resistance. Beyond that it is a dropping vertical axis work - leave it to a professional. On Staubli brakefault: the only safe self-action is stopping the axis, holding power off and supporting the arm mechanically; gap measurement, torque testing and brake replacement are engineer work.

How we diagnose brake faults on site

Staubli brakefault belongs to the brake family. On Staubli brakefault the failing stage is drive modules plus the 24 V external supply circuit (24VEXT alarms point there) on the CS8 / CS9 - the electromagnetic brake: brake supply, coil, friction lining and mechanical gap - directly tied to whether an axis can drop. We start reading Staubli brakefault at the pendant error list and VAL3 log, with cabinet module indicators.

The chain involved in Staubli brakefault runs: brake control signal -> brake supply circuit -> electromagnetic coil -> friction lining and disc -> axis holding.

If Staubli brakefault shows a slow drop after power-off: Brakes are wear parts: the lining thins with use, braking torque falls and the gap grows. The signature is a slow axis drop after power-off, or failure to hold under heavier load. We measure actual gap and holding torque against factory figures, and inspect the lining surface for oil - contamination collapses the friction coefficient, and adjusting the gap will not fix that; it needs cleaning or replacement. After any brake change we run a static hold test and hand over only when there is no creep.

Field notes on this page cover Staubli brakefault (Axis Brake Fault — Axis Drops on Power-Off); written by the Henghuan repair team, updated 2026-10-01.

Not sure? Don't force it — contact an engineer

Share the alarm code, machine model and the operating condition at the moment of the alarm. Our engineers are highly experienced with Staubli brakefault, and remote diagnosis (phone/video) is completely free.

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Related Brakes alarms

3453 — Deviation Between Safe and Non-Safe Encoders (DSI) SEG-4 — Amplifier Fault — DF Contactor Open (7-Segment Code 4) NoDriveCfg — Internal Error DRIVE NoDriveConfiguration (All Axes) ArmPowerRefused — Arm Power Enable Request Refused Fieldbus33 — Internal Error on Fieldbus Board — Status 33 EStopChain — Emergency Stop Circuit Open — Power Cannot Enable
Same family: this code belongs to the Brake alarms family - the page collects all Brake-family codes we have handled, with the common inspection order and spares.
Other brands: we also keep field-fix libraries for Epson · Nachi · Omron and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the Staubli brakefault alarm mean?

An axis falls when power is removed, or the brake release command does not free the axis; brake behavior is inconsistent between axes. Our engineers run into this alarm every week on Staubli CS8 / CS9 (VAL3) controllers, and a single on-site inspection usually identifies the problem. Staubli brakefault sits in the brake family; on our work orders the highest-frequency trigger for this code is "Brake coil open or shorted".

QCan I clear a Staubli brakefault alarm myself?

Whether Staubli brakefault clears on its own depends on the outcome of "Measure the brake coil resistance". Finish the flow with "Replace the brake/motor assembly if the brake is seized" to confirm Staubli brakefault - do not skip it. If that step is clean, the second most frequent cause on Staubli brakefault is "24 V brake supply wiring fault". After clearing Staubli brakefault, watch it for one shift. A second trip means stop and let an engineer arrive with the right test gear for a dropping vertical axis.

QWith a brake alarm like Staubli brakefault, can we keep producing for now?

The commonest causes we see on Staubli brakefault are "Brake coil open or shorted, 24 V brake supply wiring fault, Mechanically seized brake", so we stock the van against those. For Staubli brakefault specifically, we carry the brand's common brake assemblies, relays and supply modules; every change ends with a static hold test. For Staubli brakefault, brake faults carry drop risk so we prioritise them, and after replacement we hold-test on site before handover. Before we roll, tell us what Staubli brakefault shows on the pendant error list and VAL3 log, with cabinet module indicators and what the machine was doing - phone or video triage is free.

The content on Staubli brakefault was written by Henghuan Robotics service engineers from hands-on repair experience. Alarm descriptions are our own reference summary and may differ by controller or software version — defer to Staubli documentation, or contact us to confirm. Henghuan is an independent service provider with no affiliation or endorsement by Staubli.