Troubleshooting#

Device Creation Failures#

Symptom: Failed to create device after N attempts

Solutions:

  • Verify LMX(WMX Runtime) is installed: ls /opt/lmx/lib/libwmx3api.so

  • Ensure you are running with sudo

  • Check that no other WMX application is running (lock contention causes error code 297)

  • If the error persists after stopping other applications, reboot to clear stale device locks

EtherCAT Scan Failures#

Symptom: Failed to scan network

Solutions:

  • Verify the EtherCAT cable is connected to the correct dedicated Ethernet port

  • Ensure all servo drives are powered on

  • Check the eni/ directory has the correct EtherCAT Network Information files for your servo drives

  • Verify the EtherCAT Ethernet port does not have an IP address assigned

Communication Start Failures#

Symptom: Failed to start communication

Solutions:

  • Check that the EtherCAT network scan succeeded (look for earlier scan errors in the log)

  • Verify servo drives are properly daisy-chained (IN port to OUT port)

  • Remove any IP address from the EtherCAT network interface

  • Check the WMX engine status:

    ros2 service call /wmx/engine/get_status std_srvs/srv/Trigger

Joint States All Zero#

Symptom: /joint_states publishes but all position values are zero.

Solutions:

  • Verify engine is in Communicating state (see above)

  • Check that servo drives are enabled (no amplifier alarms):

    ros2 topic echo /wmx/axis/state --field amp_alarm

  • Verify wmx_param_file_path in the config YAML points to the correct WMX parameter XML file for your robot

  • Clear alarms and re-enable servos:

    ros2 service call /wmx/axis/clear_alarm wmx_ros2_message/srv/SetAxis \
  "{index: [0,1,2,3,4,5], data: [0,0,0,0,0,0]}"

Servo Alarm Errors#

Symptom: Servo drives report amplifier alarms; motion commands are rejected.

Solutions:

  • Clear alarms via the service:

    ros2 service call /wmx/axis/clear_alarm wmx_ros2_message/srv/SetAxis \
  "{index: [0,1,2,3,4,5], data: [0,0,0,0,0,0]}"

  • Check for physical obstructions or overcurrent conditions on the robot

  • Verify gear ratios and polarities match the physical servo configuration

Trajectory Execution Failures#

Symptom: FollowJointTrajectory goal is aborted with a WMX error code.

Solutions:

  • Check that the trajectory has at most 1000 waypoints

  • Verify all servos are enabled and in the correct mode

  • Check the WMX error description in the action result error_string

Gripper Not Responding#

Symptom: Gripper open/close service calls succeed but the gripper does not move.

Solutions:

  • Verify the I/O module is part of the EtherCAT daisy chain

  • Check EtherCAT communication is active (engine state = Communicating)

  • Test the I/O directly:

    ros2 service call /wmx/set_gripper std_srvs/srv/SetBool "{data: true}"

Nodes Not Found#

Symptom: ros2 pkg list | grep wmx returns nothing.

Solutions:

  • Source the workspace: source ~/wmx_ros2_ws/install/setup.bash

  • Rebuild if needed: cd ~/wmx_ros2_ws && colcon build

  • Check the two-stage build was done correctly (message package first). See Getting Started.

Build Errors#

Symptom: Linker errors referencing coremotionapi, wmx3api, or other WMX libraries.

Solutions:

  • Verify LMX(WMX Runtime) libraries exist: ls /opt/lmx/lib/

  • Ensure LD_LIBRARY_PATH includes /opt/lmx/lib/:

    export LD_LIBRARY_PATH=/opt/lmx/lib:$LD_LIBRARY_PATH

  • Install missing ROS2 dependencies:

    cd ~/wmx_ros2_ws
rosdep install --from-paths src --ignore-src -y

Getting Help#

For additional support, contact your MOVENSYS representative or file an issue on the project repository.