Hello @Pasquale Sacco If I understand your problem, you are trying to find the reaction force of translating block on the rotating block, right?
If yes, I'm not an expert but I have an Idea, Try, "Composite Sensing/Torque Sensing" instead of, "Sensing" in the Prismatic joint properties.
Constraint force acts on entire joints (constraint force or torque applied on the joint) where are Total force gives you the, Net sum of all forces and torques acting between the base and follower.
I hope this helps! Good luck!
Regards,
Yatish.
