What the 0x21 alarm means

The commanded motion exceeds the robot's working space, so no inverse solution exists. Any motion mode can trigger this when the target is beyond reach. This is one of the faults our repair team handles on Dobot Magician / MG400 / M1 / CR (DobotStudio) systems — the cause is usually identifiable within the first on-site inspection.

Most common causes

  • Target point taught or computed outside the working envelope
  • Wrong coordinate frame making a valid point appear out of reach
  • End-effector offset not accounted for
  • Part position drifted beyond the taught reach
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 whether the arm can physically reach the target by jogging there
  2. Verify the active coordinate frame and tool offset
  3. Re-teach the point within the workspace
  4. Check part presentation consistency
  5. Run the clear-alarm script in DobotStudio and re-test
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 Motion & Path alarms

0x20 — Inverse Kinematics Singularity 0x22 — Inverse Kinematics Over Joint Limit 0x30 — Joint 1 Overspeed 0x31 — Joint 2 Overspeed 0x32 — Joint 3 Overspeed 0x33 — Joint 4 Overspeed
Other brands: we also keep field-fix libraries for FANUC · KUKA · ABB and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the Dobot 0x21 alarm mean?

The commanded motion exceeds the robot's working space, so no inverse solution exists. Any motion mode can trigger this when the target is beyond reach. In field practice it belongs to the motion & path family of faults.

QCan I clear a Dobot 0x21 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 Dobot documentation or contact us. Henghuan is an independent service provider, not affiliated with or endorsed by Dobot.