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 most common faults in our repair logs for the Dobot Magician / MG400 / M1 / CR (DobotStudio) platform, and the first inspection typically locates the cause.

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: Field experience says the first cause is the most likely — verify it before moving on to the rest.

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: For Dobot 0x21, this alarm family points at arm motion control: after a reset the arm can move unexpectedly, and anyone inside the working envelope is at strike and pinch risk. What you can check yourself first is Check whether the arm can physically reach the target by jogging there; the arm working envelope handling is not a DIY job.

How we diagnose motion alarms on site

Dobot 0x21 belongs to the motion & path family. On Dobot 0x21 the failing stage is joint-integrated drive modules (collaborative models dominate) on the Dobot controllers (CR / MG / Nova series companions) - the gap between command and execution: trajectory planning, joint limits, singularities, following error and mechanical resistance. We start reading Dobot 0x21 at DobotStudio / app alarm messages; error codes are hexadecimal with a 0x prefix.

The chain involved in Dobot 0x21 runs: program command -> trajectory planner -> joint targets -> servo execution -> actual position feedback -> deviation compare.

If Target point taught or computed outside the working envelope on Dobot 0x21 comes with a feeling of drag, the direction is clear: Following error that stays high on one axis only is usually rising mechanical resistance, not a weak servo. We turn the axis by hand with the brake released to feel smoothness, and listen to the reducer for once-per-revolution knocking - a single tick per turn on an RV reducer usually means internal bearing or cycloid damage. Grease that is black, dry or carries metal powder is the plainest evidence. Left alone, this graduates from a motion alarm to a scrapped reducer.

Field notes on this page cover Dobot 0x21 (Inverse Kinematics No Solution — Out of Workspace); written by the Henghuan repair team, updated 2026-10-01.

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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
Same family: this code belongs to the Motion & path alarms family - the page collects all Motion & path-family codes we have handled, with the common inspection order and spares.
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. This is one of the most common faults in our repair logs for the Dobot Magician / MG400 / M1 / CR (DobotStudio) platform, and the first inspection typically locates the cause. Dobot 0x21 sits in the motion & path family; on our work orders the highest-frequency trigger for this code is "Target point taught or computed outside the working envelope".

QCan I clear a Dobot 0x21 alarm myself?

Whether Dobot 0x21 clears on its own depends on the outcome of "Check whether the arm can physically reach the target by jogging there". Finish the flow with "Run the clear-alarm script in DobotStudio and re-test" to confirm Dobot 0x21 - do not skip it. If that step is clean, the second most frequent cause on Dobot 0x21 is "Wrong coordinate frame making a valid point appear out of reach". Do not chase takt through a repeating Dobot 0x21. Left alone, motion & path faults tend to graduate from repairable to must-replace.

QFor motion alarms like Dobot 0x21, can you triage remotely first?

The commonest causes we see on Dobot 0x21 are "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", so we stock the van against those. For Dobot 0x21 specifically, we carry mechanical and configuration items: grease, limit switches, drag-chain segments, encoder cables and the parameter sheets for common reducers. For Dobot 0x21, motion alarms can often be narrowed remotely first, so an on-site visit is not always immediate. Before we roll, tell us what Dobot 0x21 shows on DobotStudio / app alarm messages; error codes are hexadecimal with a 0x prefix and what the machine was doing - phone or video triage is free.

The notes on Dobot 0x21 were summarized by the Henghuan Robotics repair team from on-site service. The alarm interpretation is our empirical summary for troubleshooting reference and may vary by controller and software version — please check Dobot documentation or contact us with questions. Henghuan is an independent service provider, not affiliated with or endorsed by Dobot.