Hello Viktor,
A workobject’s User frame is referenced from the world coordinate sytem. The Object frame is referenced from the User Frame coordinate system.
This comes in handy when you want displace movements in the User coordinate system. It is used in palletizing for layer control. You teach the User frame of your workobject at a top corner of the pallet. To go to the next layer you put the value of the height of the next layer in the trans.z value for the Object frame. You use the the same movement routine that was used on the first layer to move to the new layer positions.
Another example is a table with 2 fixtures. You only need to program 1 fixture that has a User Frame and Object frame defined. By changing the values in the Object frame you can execute the same routine at the other fixture. If for some reason the entire table moves, all you have to do is re-teach your User frame to have your positions in the correct place.
Another example is vision. You can teach a model using a User frame. To offset the x,yand angle you could put those values into the object frame to move the robot’s positions.
Hope this helps. The Rapid Overview Manual (3HAC16580-1_revG) has a good explaination.
BR Jim Proulx