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QL-200 error code reference

Error codes on the QL-200 autonomous mobile robot follow the pattern E-<SUBSYSTEM>-<NUMBER>. Subsystems: NAV (navigation), LOC (localization), SEN (sensors), MOT (drive train), BAT (battery), NET (fleet network), SAF (safety).

E-NAV-204 Goal aborted after recovery attempts

The behaviour tree navigator aborted the current goal after exhausting its recovery behaviours (clear costmap, spin, back up). This is almost always a consequence, not a root cause. Look at the 5 minutes before the abort for localization (E-LOC-101), sensor (E-SEN-410) or drive (E-MOT-5xx) problems. A blocked aisle shows as repeated "Failed to make progress" warnings without other subsystem errors.

E-LOC-101 Localization confidence low

AMCL pose covariance exceeded the safe threshold (covariance above 0.5). The robot no longer trusts its position on the map and will stop accepting goals. Common causes: lidar data missing or degraded (see E-SEN-410), the map no longer matching the environment (moved racks), or reflective surfaces. Recovery: restore sensor data, then re-localize at a known docking marker.

E-SEN-410 Lidar scan timeout

No scan was received from the safety lidar within the 500 ms deadline. Isolated timeouts are tolerated. Repeated timeouts within minutes indicate a dirty optical window, a loose Ethernet connector or a failing lidar. A preceding "Window contamination warning" with dirt_level above 0.50 points strongly to a dirty window. See the lidar maintenance procedure.

E-MOT-502 Motor overcurrent

Drive motor current exceeded the 15 A continuous limit. Sustained overcurrent on a single side while the other side is normal indicates mechanical resistance on that wheel: dragging brake, debris wrapped around the axle or a failing gearbox bearing. Sustained overcurrent raises motor temperature and battery consumption.

E-MOT-503 Thermal derating active

Motor temperature passed 75 C and the controller is limiting torque and speed to protect the winding. The robot keeps operating at reduced speed. Above 85 C it performs a controlled stop. Derating is a symptom; investigate E-MOT-502 and E-MOT-507 for the cause.

E-MOT-507 Brake release feedback mismatch

The electromagnetic brake was commanded open but the feedback sensor did not confirm full release. A partially engaged brake drags the wheel, causing overcurrent (E-MOT-502), heating (E-MOT-503) and abnormal battery drain. Take the robot out of service and inspect the brake air gap; this is a known wear item.

E-BAT-301 Battery low

State of charge dropped below 15 % before the robot reached a charger. Occasional occurrences point at mission scheduling; frequent occurrences on one robot point at abnormal consumption (drive train friction) or battery ageing.

E-NET-601 Fleet heartbeat timeout

The robot missed heartbeats to the fleet manager for more than 3 seconds. The robot continues its current mission but cannot receive new ones. If timeouts cluster in one area for several robots, the cause is site infrastructure (access point coverage or channel interference), not the robots. Correlate with rssi below -80 dBm and the reported access point id.

E-SAF-001 Protective stop

The safety scanner protective field was violated and the robot stopped. Motion resumes automatically when the field is clear. Short stops in busy aisles with people or forklifts are expected behaviour and not a fault. Investigate only if stops do not clear, or if they happen with no obstacle present (scanner fault or field misconfiguration).