Articulation force torque sensor reading is zero

@Hammad_M @kstorey I’ve tried articulation force sensor , the Xform attached to panda leftfinger is set as articulation force sensor

However when the tool tip tries to move down but stopped the table, the force torque sensor reading is alwasys zero

I’m wondering what’s the problem.

Is there any 6-d force torque sensor to measure extenal force toque executed on the robot end-effector or joint?