Error Codes

When the arm detects an error, it stops and reports an error code. For how to read the arm’s state from its LEDs, see LED Status.

Reading an Error

There are two levels of detail available when an error occurs:

• The error code (the summary state, e.g. Joint Limit Exceeded), shown in the log and listed in the Reported text column of the Error Code Reference below.

• The detailed log line. For runtime errors the Arm Controller also logs a message that names the specific joint and the offending value (for example the allowed range and what the motor actually reported). Read it to pinpoint which joint errored and by how much, e.g.

  [Motor Interface] Joint 3 position limit exceeded: expected in range [-3.054, 3.054], motor reported 3.210. Setting to idle.
  

When a runtime error occurs, the Arm Controller sets all joints to idle as a safety measure.

Note

Joint numbering. Joints are 0-indexed and the gripper is the last joint. See Joints and Indexing for details.

Tip

Seeing the logs. By default the library logs to stderr in C++ and to Python’s logging module in Python. To see more detail, raise the verbosity with set_log_level(...). To capture or redirect the messages yourself (for example into your application’s logger), install a handler with set_logger_backend(...).

Clearing an Error

After applying the relevant solution from the Error Code Reference below, do one of the following to clear the error:

• Restart the Arm Controller (recommended).

• Clear the error at the driver’s configure(...) call or with clear_error().

If the problem persists, please submit a support ticket at Trossen Robotics Support.

Error Code Reference

The codes are grouped into families that share a root cause and fix. The Reported text column is the exact error string the Arm Controller reports.

Startup Errors

The Arm Controller could not bring up a hardware interface while booting, so it will not accept control commands.

• Check the cabling.

• Power-cycle the Arm Controller.

• If the error persists, submit a support ticket.

Code	Name	Reported text	What it means
1	Ethernet Init Failed	Controller's Ethernet manager failed to initialize	The Arm Controller’s Ethernet manager failed to initialize at boot.
2	CAN Init Failed	Controller's CAN interface failed to initialize	The Arm Controller could not bring up the CAN bus to the arm at boot. While in this state it only answers handshake and log requests, so you may also see code 12.

Controller-to-Arm Communication and Motor Faults

The Arm Controller could not exchange messages with a joint motor over the CAN bus, or a motor reported an error. These almost always point to the controller-to-arm cabling, the cabling inside the arm, or an individual motor. The log names the specific motor, and motors are 0-indexed (so motor 0 is the first joint).

• Trace the cable to that motor and reseat its connectors on both ends, then power-cycle the Arm Controller.

• If the error persists, replace that motor’s cable (see the cable replacement guides in Service and Maintenance).

• If a specific joint keeps failing after reseating and replacing its cable, submit a support ticket.

Code	Name	Reported text	What it means
3	Joint Command Failed	Controller's CAN interface failed to send a message	The Arm Controller failed to send a command to a motor over the CAN bus.
4	Joint Feedback Failed	Controller's CAN interface failed to receive a message	The Arm Controller stopped receiving feedback from a motor (reported after several consecutive losses).
5	Joint Clear Error Failed	Joint clear error command failed	The command to clear a motor’s error did not succeed.
6	Joint Enable Failed	Joint enable command failed	The command to enable a motor did not succeed.
7	Joint Disable Failed	Joint disable command failed	The command to disable a motor did not succeed.
8	Joint Set Home Failed	Joint home calibration command failed	The home calibration command for a motor did not succeed. See Service and Maintenance for the homing procedure.
9	Joint Disabled Unexpectedly	Joint disabled unexpectedly	A motor reported that it disabled itself; the Arm Controller sets it to idle. Check the log for the motor’s own error code.

Thermal Protection

A motor overheated, and the Arm Controller set the arm to idle to protect it.

• Power off the Arm Controller and let the joint cool down.

• For sustained high-effort tasks, reduce the payload or duty cycle, or improve cooling.

Code	Name	Reported text	What it means
10	Joint Overheated	Joint overheated	A motor’s driver or rotor temperature exceeded its limit.

Driver and Firmware Protocol Errors

The Arm Controller received a command it does not recognize. This most often means the driver and firmware versions are mismatched, but it can also happen if another device on the network sends unrecognized packets to the Arm Controller.

• Make sure the driver and Arm Controller firmware share the same minor version (see Firmware Upgrade).

• Make sure no other device is sending traffic to the Arm Controller.

Code	Name	Reported text	What it means
11	Invalid Mode	Invalid mode command received	An unrecognized mode value was received.
12	Invalid Robot Command	Invalid robot command indicator received	An unrecognized command indicator was received. Can also appear if any command other than handshake or log retrieval is sent after a failed initialization (see code 2).
13	Invalid Configuration Address	Invalid configuration address	An unrecognized configuration address was received.

Command and Input Errors

The Arm Controller rejected an input you sent, usually because of a scripting issue. The log names the joint and the offending value.

• Make sure each joint is in the mode your input targets before sending it.

• Keep inputs within the configured joint limits (see Joint Limits).

• Guard against non-finite values (NaN or infinity), and avoid commanding near singular configurations in Cartesian space.

Code	Name	Reported text	What it means
14	Robot Input Mode Mismatch	Robot input with modes different than configured modes received	The modes in your robot input do not match the configured modes.
15	Joint Limit Exceeded	Joint limit exceeded	A joint’s position, velocity, or effort went outside its configured limit (plus tolerance), and the Arm Controller set the arm to idle. The log states which joint, which limit, the allowed range, and the reported value.
16	Robot Input Infinite	Robot input with infinite values received	An input contained a non-finite value (NaN or infinity); the Arm Controller rejected it and kept the previous inputs.

Note

Singular configurations. A singular configuration is an arm pose where joints align such that the arm loses the ability to move its end effector in some direction (for example with the elbow fully extended). Near a singularity, small Cartesian motions demand very large joint velocities and efforts, which can trip codes 15 and 16. When operating in Cartesian space, plan paths that stay clear of these poses, or switch to joint-space control through them.