What the 34200 alarm means

The computer unit lost the drive communication bus entirely — every axis is offline and the robot cannot move. This is one of the faults our repair team handles on ABB IRC5 / OmniCore (RobotWare) systems — the cause is usually identifiable within the first on-site inspection.

Most common causes

  • Drive unit main power missing (breaker, fuses, incoming supply)
  • Faulty drive communication cable or node
  • Computer unit or drive unit hardware failure
  • Blown cabinet fuses after a supply disturbance
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. Check the drive unit LEDs and cabinet supply breakers/fuses
  2. Measure incoming three-phase power at the cabinet
  3. Reseat the drive communication cables
  4. Power-cycle the controller; if the bus stays down, isolate computer unit vs. drive unit by swap or service diagnostics
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.

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Related Drive & Power Stage alarms

34316 — Motor Current Error 34251 — Missing Phase of Input Power 34400 — DC Link Voltage Too High
Other brands: we also keep field-fix libraries for Yaskawa · Universal Robots · Kawasaki and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the ABB 34200 alarm mean?

The computer unit lost the drive communication bus entirely — every axis is offline and the robot cannot move. In field practice it belongs to the drive & power stage family of faults.

QCan I clear a ABB 34200 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 ABB documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by ABB.