What the h# alarm means

The amplifier for the indicated joint exceeded its temperature limit. In our Omron service archive this alarm on SmartController (ACE / Viper / Cobra) systems shows up constantly, and the first on-site inspection almost always locates it.

Most common causes

  • High ambient temperature
  • Blocked cabinet/chassis airflow
  • Sustained heavy duty cycle
  • Failing cooling fan
Field note: The first cause is the most common in the field — check it first, then work through the rest.

Step-by-step field fix

  1. Allow the amplifier to cool
  2. Check and clean cooling paths and fans
  3. Reduce the duty cycle or add dwell time
  4. Measure ambient temperature at the chassis
  5. Replace failed fans; confirm normal temperature at duty
Safety first: For OMRON high-temp-amp, 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. The self-serviceable action is Allow the amplifier to cool; anything past that falls under the DC bus and power stage and needs a certified engineer. On OMRON high-temp-amp: 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

OMRON high-temp-amp belongs to the drive & power stage family. On OMRON high-temp-amp the failing stage is integrated drive units (amplifier and supply in one housing) on the OMRON robot controllers (including SCARA and cobot companions) - the fault sits on the energy chain: mains input, rectification, DC bus, braking resistor, inverter power devices and the drive board. We start reading OMRON high-temp-amp at controller status indicators and the software error list (letter prefixes RC / SW / V / M / D / A / E).

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

High ambient temperature is common on OMRON high-temp-amp, but look at the duty cycle: Cells with high-inertia loads or frequent start-stop cycles return far more regenerative energy than a plain transfer cell, and the braking resistor lives in a hot cycle that shortens its life. When we suspect this family we ask what changed: if the takt was raised recently or a heavier fixture went on, the alarm cluster usually lines up with that process change. Replacing the resistor alone will not fix it - the chopper rating and resistor wattage have to be re-checked against the new duty.

Field notes on this page cover OMRON high-temp-amp (High Temperature — Amplifier (Joint N)); written by the Henghuan repair team, updated 2026-10-01.

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Related Drive & Power Stage alarms

D# (-1021) — Duty Cycle Exceeded (Joint N) 24 — 24V Supply Fault A# — Amplifier Fault (Joint N) hV — High Voltage Bus Fault
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 ESTUN · INOVANCE · EFORT and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the OMRON high-temp-amp alarm mean?

The amplifier for the indicated joint exceeded its temperature limit. In our Omron service archive this alarm on SmartController (ACE / Viper / Cobra) systems shows up constantly, and the first on-site inspection almost always locates it. OMRON high-temp-amp sits in the drive & power stage family; on our work orders the highest-frequency trigger for this code is "High ambient temperature".

QCan I clear a OMRON high-temp-amp alarm myself?

Whether OMRON high-temp-amp clears on its own depends on the outcome of "Allow the amplifier to cool". Finish the flow with "Replace failed fans; confirm normal temperature at duty" to confirm OMRON high-temp-amp - do not skip it. If that step is clean, the second most frequent cause on OMRON high-temp-amp is "Blocked cabinet/chassis airflow". Two attempts and still there means stop: OMRON high-temp-amp involves the DC bus and power stage, and running OMRON high-temp-amp on can turn a repairable fault into a replacement.

QFor drive/power alarms like OMRON high-temp-amp, what spares do you bring on site?

The commonest causes we see on OMRON high-temp-amp are "High ambient temperature, Blocked cabinet/chassis airflow, Sustained heavy duty cycle", so we stock the van against those. For OMRON high-temp-amp 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 OMRON high-temp-amp, drive alarms usually stop the whole line, so they sit at the front of our dispatch queue. Before we roll, tell us what OMRON high-temp-amp shows on controller status indicators and the software error list (letter prefixes RC / SW / V / M / D / A / E) and what the machine was doing - phone or video triage is free.

This page on OMRON high-temp-amp is based on the field experience of the Henghuan Robotics repair team. Alarm explanations are our own summary for troubleshooting reference and may differ across controller and software versions — if unsure, verify against Omron documentation or reach out to us. Henghuan is an independent service provider with no affiliation or endorsement by Omron.