What the 24 alarm means

The 24 VDC control supply to the SmartController is missing or out of range; logic, brakes and I/O cannot operate. This is one of the faults our repair team handles on Omron SmartController (ACE / Viper / Cobra) systems — the cause is usually identifiable within the first on-site inspection.

Most common causes

  • 24 V power supply off or failed
  • 24 V cable disconnected or blown fuse
  • Overloaded 24 V rail from peripheral devices
  • Loose terminal
Field note: the first item on this list is what we find most often on real machines. Check it before you go deeper.

Step-by-step field fix

  1. Verify the 24 VDC supply is on and measures correctly
  2. Check the 24 V cable and connector to the SmartController
  3. Check fuses and terminal tightness
  4. Disconnect non-essential loads on the 24 V rail
  5. Replace the supply if it cannot hold voltage
Safety first: never bypass safety circuits or force contactors closed. If the alarm involves E-stop chains, brakes or drive power, and you are not a trained robot technician, contact a professional — wrong moves here can cost you a robot or an injury.

Still stuck? Get an engineer on the phone — right now

Tell us the alarm code, the robot model and what was happening when the alarm came up. Our engineers run these diagnostics every day, and remote diagnosis by phone or video call is free.

Get a Free Remote Diagnosis See Repair Services

Hotline: +86-20-39029800 · WhatsApp: +86-188-1886-2860

Related Drive & Power Stage alarms

D# (-1021) — Duty Cycle Exceeded (Joint N) A# — Amplifier Fault (Joint N) h# — High Temperature — Amplifier (Joint N) hV — High Voltage Bus Fault
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 24 alarm mean?

The 24 VDC control supply to the SmartController is missing or out of range; logic, brakes and I/O cannot operate. In field practice it belongs to the drive & power stage family of faults.

QCan I clear a Omron 24 alarm myself?

Sometimes. Work through the step-by-step checks on this page — the first listed cause is what we find most often in the field. If the alarm returns after two attempts, or the fault involves power, brakes or safety circuits, stop and call a qualified robot service engineer.

QHow fast can a Henghuan engineer help?

On-site response in the Pearl River Delta within 30 minutes to 3 hours, across mainland China in 1-3 business days, and worldwide within 2-5 business days. Remote diagnosis by phone/WhatsApp/video is available immediately.

Written by the Henghuan Robotics repair team from field service experience. Alarm descriptions are our own summary for troubleshooting reference and may vary by controller and software version — when in doubt, check your Omron documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by Omron.