What the OverTemp alarm means

Drive temperature monitoring trips; the robot derates or stops to protect the power stage. This fault ranks high in our Staubli CS8 / CS9 (VAL3) service records, and the first site inspection usually finds the source.

Most common causes

  • Cabinet fan failure or blocked airflow
  • High ambient temperature
  • Sustained high-duty operation
  • Dust-clogged heat sinks
Field note: The first cause shows up most on real machines, so verify it before you go further.

Step-by-step field fix

  1. Check cabinet fans and airflow paths
  2. Clean heat sinks and filters
  3. Measure ambient temperature at the cabinet
  4. Review the duty cycle and peak loads
  5. Replace failed fans; the robot should recover after cooling
Safety first: For Staubli overtemp, this alarm family involves the DC bus, which sits at several hundred volts and stays charged for minutes after power-off - touching terminals is a shock hazard. What you can check yourself first is Check cabinet fans and airflow paths; the DC bus and power stage handling is not a DIY job. On Staubli overtemp: checking incoming voltage at the disconnect and looking at breakers and fuses is fine to do yourself; opening the cabinet to touch bus terminals or pulling power modules needs a qualified electrician.

How we diagnose drive alarms on site

Staubli overtemp belongs to the drive & power stage family. On Staubli overtemp the failing stage is drive modules plus the 24 V external supply circuit (24VEXT alarms point there) on the CS8 / CS9 - the fault sits on the energy chain: mains input, rectification, DC bus, braking resistor, inverter power devices and the drive board. We start reading Staubli overtemp at the pendant error list and VAL3 log, with cabinet module indicators.

The chain involved in Staubli overtemp runs: three-phase mains -> rectifier -> DC bus (bus capacitors) -> brake chopper / braking resistor -> inverter (IGBT) -> motor.

Bottom line up front: Cabinet fan failure or blocked airflow is the first suspect for Staubli overtemp, but read it along the energy chain: Any link on this chain dropping voltage shows up at the end as a drive alarm, so order matters. We measure the mains first: more than 3% phase imbalance is enough to sag the bus under load, and plenty of bus over/under-voltage alarms are actually a grid problem wearing a robot costume. Mains fine, then the bus capacitors - bulged cases, weeping electrolyte or a lifted vent mean replacement; capacitance down 20% or more cannot hold the bus during braking. Last, the braking resistor: healthy values sit in the tens of ohms depending on rating, and an open or drifted resistor trips regenerative overvoltage directly.

Field notes on this page cover Staubli overtemp (Drive / Cabinet Overtemperature); written by the Henghuan repair team, updated 2026-10-01.

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Related Drive & Power Stage alarms

SEG-4 — Amplifier Fault — DF Contactor Open (7-Segment Code 4) DCBusUV — DC Bus Undervoltage at Power-Up (Pre-charge Failure) 24VExt — External 24V Supply Fault (Safety System Dropout)
Same family: this code belongs to the Drive & power stage alarms family - the page collects all Drive & power stage-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 overtemp alarm mean?

Drive temperature monitoring trips; the robot derates or stops to protect the power stage. This fault ranks high in our Staubli CS8 / CS9 (VAL3) service records, and the first site inspection usually finds the source. Staubli overtemp sits in the drive & power stage family; on our work orders the highest-frequency trigger for this code is "Cabinet fan failure or blocked airflow".

QCan I clear a Staubli overtemp alarm myself?

Whether Staubli overtemp clears on its own depends on the outcome of "Check cabinet fans and airflow paths". Finish the flow with "Replace failed fans; the robot should recover after cooling" to confirm Staubli overtemp - do not skip it. If that step is clean, the second most frequent cause on Staubli overtemp is "High ambient temperature". If Staubli overtemp returns after two clears, or the checks point at Cabinet fan failure or blocked airflow, stop the cell and call a professional robot repair engineer.

QFor drive/power alarms like Staubli overtemp, what spares do you bring on site?

The commonest causes we see on Staubli overtemp are "Cabinet fan failure or blocked airflow, High ambient temperature, Sustained high-duty operation", so we stock the van against those. For Staubli overtemp specifically, we stock the van along the energy chain: braking resistors, bus capacitors, input fuses, drive-board supply parts and the common power modules for the brand. For Staubli overtemp, drive alarms usually stop the whole line, so they sit at the front of our dispatch queue. Before we roll, tell us what Staubli overtemp 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.

This page on Staubli overtemp was compiled from actual repair records of the Henghuan Robotics repair team. Alarm notes are our own summary for troubleshooting reference only and may vary with controller and software version — please consult Staubli documentation or contact us if in doubt. Henghuan is an independent service provider, not affiliated with or endorsed by Staubli.