Multi-turn error — clearing procedure (AI Worker)

If you see logs like the following while running bringup, a multi-turn error has occurred.

[ros2_control_node-1] [ID:034] RX_PACKET_ERROR : [RxPacketError] Hardware error occurred. Check the error at Control Table (Hardware Error Status)!
[ros2_control_node-1] [comm_id:034][ID:034] Request ping	 - RX_PACKET_ERROR : [RxPacketError] Hardware error occurred. Check the error at Control Table (Hardware Error Status)!
[ros2_control_node-1] [ReadItem][ID:034][comm_id:034] RX_PACKET_ERROR : [RxPacketError] Hardware error occurred. Check the error at Control Table (Hardware Error Status)!
[ros2_control_node-1] [comm_id:034][ID:034] Error Code Details: 0xc (Multi-turn Error): An issue has occurred with the Multi-turn IC
[ros2_control_node-1] [ID:034] Rebooting...

In this example, the multi-turn error is on Dynamixel ID 34.

Use the steps below to clear the multi-turn error.

How to clear the multi-turn error

1. Align the home position

Press the E-stop, align the slit marks while moving the arm toward the home (zero) position, then release the E-stop once alignment is complete.

You only need to set the pose for the joint(s) you plan to clear (for example, the Dynamixel ID shown in the error log). It is not required to align every joint on the arm if the fault is isolated—but keep the arm supported and safe while doing so.

Important: When you perform the multi-turn Clear in Dynamixel Wizard later (Tools → Encoder battery change), the robot must still be in this physically correct alignment. The clear procedure assumes the mechanism matches the home / slit reference at that moment; if the pose is wrong, the encoder state may not clear correctly or the arm may not behave as expected afterward.

Home positions (joint index, Dynamixel ID): the figures below are left arm references. Use the same idea for the right arm if you are clearing servos on that side.

• Joint 1 (ID 1, 31)
  
• Joint 2 (ID 2, 32)
  
• Joint 3 (ID 3, 33)
  
• Joint 4 (ID 4, 34)
  
• Joint 5 (ID 5, 35)
  
• Joint 6 (ID 6, 36)
  

2. Set up the noVNC container

docker-compose.yml

services:
  novnc-server:
    container_name: novnc-server
    image: robotis/novnc-server:latest
    restart: always
    cap_add:
      - SYS_NICE
    ulimits:
      rtprio: 99
      rttime: -1
      memlock: 8428281856
    network_mode: host
    environment:
      - ROS_DOMAIN_ID=${ROS_DOMAIN_ID:-30}
      - DISPLAY=:99
      - DISPLAY_WIDTH=1920
      - DISPLAY_HEIGHT=1080
      - WEBSOCKIFY_PORT=8090
    volumes:
      - /dev:/dev
      - /dev/shm:/dev/shm
    privileged: true

Then run docker-compose up -d to start the noVNC container.

3. Open noVNC in a browser

In a Web Browser(like Chrome), open http://ffw-snpr48a{serial-number}.local:8090, substituting your robot’s serial number for serial-number. (e.g. http://ffw-snpr48a0000.local:8090)

4. Connect noVNC and Dynamixel Wizard 2.0

Connect noVNC and Dynamixel Wizard 2.0 so you can use the wizard on the robot’s desktop.

5. Configure Dynamixel Wizard 2.0 and run Scan

In Dynamixel Wizard 2.0, configure the following and run Scan:
- Select protocol to scan: Protocol 2.0
- Select port to scan: /dev/ttyUSB4 (When connecting an LG2 leader, scan ports from ttyUSB4 to ttyUSB6)
- Baud rate: 4000000 bps

6. Select the Dynamixel that reported the error

Select the Dynamixel that reported the error, then choose Tools → Encoder battery change from the top menu.

7. Clear the multi-turn error

Set Multi-turn encoder power mode to High, then perform Clear.

8. Verify with bringup

Run bringup again and confirm the error no longer appears.