What the 0x40 alarm means

Joint 1 moved to its positive limit zone; per the Dobot ALARM description, moving back out of the limit zone clears this alarm automatically. 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

  • Jog or program drove joint 1 to its positive end of travel
  • Taught point too close to the limit
  • Accumulated offset pushing the axis to the end
  • Wrong home reference after maintenance
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. Jog joint 1 back in the negative direction — the alarm resets automatically
  2. Re-teach points that sit at the limit with margin
  3. Check for unintended offset accumulation
  4. Verify home/zero reference after any maintenance
  5. Re-run the program and watch the limit margin
Safety first: For Dobot 0x40, 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 Jog joint 1 back in the negative direction — the alarm resets automatically; the arm working envelope handling is not a DIY job.

How we diagnose motion alarms on site

Dobot 0x40 belongs to the motion & path family. On Dobot 0x40 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 0x40 at DobotStudio / app alarm messages; error codes are hexadecimal with a 0x prefix.

The chain involved in Dobot 0x40 runs: program command -> trajectory planner -> joint targets -> servo execution -> actual position feedback -> deviation compare.

The clearest field clue for Dobot 0x40 is Jog or program drove joint 1 to its positive end of travel; the discriminator is this test: The most valuable judgement on motion alarms is separating software from mechanics. We take the fixture off and re-run the same path below 10% speed: if it is clean unloaded and slow, the problem is mechanical - over-heavy tooling, shifted centre of gravity, or a joint that already has drag; if it alarms even unloaded and slow, look at program points, frame calibration and whether the path crosses a singular region. No instruments needed, and it removes half the wrong turns.

Field notes on this page cover Dobot 0x40 (Joint 1 Positive Limit Reached); written by the Henghuan repair team, updated 2026-10-01.

Can't clear it yourself? Contact us for remote diagnosis

Provide the alarm code, model and the action being performed at the alarm. Our engineers have seen Dobot 0x40 many times and judge fast; phone and video remote diagnosis are both free.

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Related Motion & Path alarms

0x20 — Inverse Kinematics Singularity 0x21 — Inverse Kinematics No Solution — Out of Workspace 0x22 — Inverse Kinematics Over Joint Limit 0x30 — Joint 1 Overspeed 0x31 — Joint 2 Overspeed 0x32 — Joint 3 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 0x40 alarm mean?

Joint 1 moved to its positive limit zone; per the Dobot ALARM description, moving back out of the limit zone clears this alarm automatically. 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 0x40 sits in the motion & path family; on our work orders the highest-frequency trigger for this code is "Jog or program drove joint 1 to its positive end of travel".

QCan I clear a Dobot 0x40 alarm myself?

Whether Dobot 0x40 clears on its own depends on the outcome of "Jog joint 1 back in the negative direction — the alarm resets automatically". Finish the flow with "Re-run the program and watch the limit margin" to confirm Dobot 0x40 - do not skip it. If that step is clean, the second most frequent cause on Dobot 0x40 is "Taught point too close to the limit". After clearing Dobot 0x40, watch it for one shift. A second trip means stop and let an engineer arrive with the right test gear for the arm working envelope.

QFor motion alarms like Dobot 0x40, can you triage remotely first?

The commonest causes we see on Dobot 0x40 are "Jog or program drove joint 1 to its positive end of travel, Taught point too close to the limit, Accumulated offset pushing the axis to the end", so we stock the van against those. For Dobot 0x40 specifically, we carry mechanical and configuration items: grease, limit switches, drag-chain segments, encoder cables and the parameter sheets for common reducers. For Dobot 0x40, motion alarms can often be narrowed remotely first, so an on-site visit is not always immediate. Before we roll, tell us what Dobot 0x40 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 content on Dobot 0x40 was written by Henghuan Robotics service engineers from hands-on repair experience. Alarm descriptions are our own reference summary and may differ by controller or software version — defer to Dobot documentation, or contact us to confirm. Henghuan is an independent service provider with no affiliation or endorsement by Dobot.