Joint External Torque Exceeds Reference Value on Direct Teaching

When error [2.3506] occurs, direct teaching (hand guiding) does not start.

• The error is raised at the moment direct teaching is selected, not during motion.
• It repeats every time, often on the same joint.

[2.3506] Control module category

Joint external torque exceeds reference value when entering direct teaching ctrl
Param 1: Detailed cause

When direct teaching starts, the robot compares the torque measured in each joint with the torque it expects from its own weight and the configured payload. If the difference is too large, it treats it as an external force and refuses to enter direct teaching.

• Payload not configured — a tool, gripper or workpiece is fitted but not reflected in the payload setting.
• Something touching the robot — a cable, hose or dress pack pulling on the arm, or contact with the surroundings.
• Torque sensor calibration out of date — for example after a repair.
• A fault or wear in a joint — the torque sensor or the reducer of one joint. This needs service.

• Confirm that the tool, gripper and workpiece mass and center of gravity match the payload configured on the robot, and that the correct tool is selected.
• Check that no cable, hose or dress pack is pulling on the arm, and that the robot is not touching anything.
• Try entering direct teaching from a different posture. If it works in some postures and not others, note which.
• With the robot still and nothing touching it, look at the joint torque values on the teach pendant. A joint that shows a large value at rest points to the sensor.
• Check whether the robot was repaired recently. A repair usually needs a torque sensor calibration afterwards.

If the error continues, contact your distributor. See also What Is JTS Calibration and When Is It Needed?

• Robot model and serial number
• Software version of the controller
• The error code with its Param value, and the date and time
• The payload setting and a photo of the tool
• The joint torque values shown on the teach pendant at rest
• The controller log exported right after the error

• 2.3502 Joint torque sensor value differs from the calculated model value on entering direct teaching
• 5.7059 Joint torque has exceeded user limit in at least one joint
• 5.7023 Joint torque sensor data sequence number error occurred on Inverter board
• 2.9011 Collision has been detected