Modern FANUC robots use DCS to monitor these joint interactions in real-time, ensuring the arm does not enter a self-interference zone even during high-speed manual jogging. robodk.com Robot Axis Coupling Can Mess Your Production - RoboDK blog
FANUC uses serial pulse coders (absolute encoders). The J2 and J3 axes share a mechanical relationship via the connecting links. fanuc j2 j3 interaction
If you have replaced either axis, run this manual sequence before full power: Modern FANUC robots use DCS to monitor these
The controller calculates a "limit polygon" where the combined angles of J2 and J3 are restricted. For example, if J2 is at its extreme forward limit, J3 may be restricted from certain downward movements. If you have replaced either axis, run this
When jogging the robot in "Joint" mode, you may notice that moving J2 causes J3 to physically move as well. However, the position screen on the FANUC Teach Pendant often shows only the J2 value changing, because the controller is internally "hiding" the compensation it is performing for J3.