This thread collects debugging information for ServoJ returning error code -4 in the Fairino C++ SDK.

Status

Open collection. SetDO and MoveJ may work while ServoJ fails, which suggests the connection is alive but ServoJ-specific requirements are not met.

Symptoms

  • C++ SDK connects to the robot.
  • Basic commands such as SetDO or MoveJ work.
  • ServoJ returns -4.
  • The same robot may work through WebApp or other motion commands.

Known checks

  • Confirm the SDK version matches the robot software version.
  • Check whether the robot is in automatic mode and ready for servo control.
  • Verify ServoJ input units, joint order and limits.
  • Check whether the command must be sent at a fixed cycle time.
  • Make sure no other program or SDK process is controlling motion at the same time.

Please reply with

  • Robot model
  • Robot software version
  • C++ SDK version
  • Minimal ServoJ code sample
  • Full return code and robot state