I use licecap on Mac to capture gif files.
I guess I’m not sure I totally understand what you are trying to do. What point are you trying to start your move from? With what I did I only moved in the Z-axis 100mm per the following quote from your initial post:
“…but the important thing is that the difference between the two poses is only in the z-axis and has the value of 100mm.”
If you ware looking for the robot to move 100 mm in the Z-axis of the TCP then you would use the following commands
global var_2 = get_forward_kin()
global var_3 = p[0,0,var_2[2]-100/1000,0,0,0]
movel(pose_trans(get_forward_kin(), var_3), a=1.2, v=0.25)
If you are going to translate the pose you only need to fill in the value(s) of the new pose that you want to be different, so in this case you would only use the z value. This causes the robot to move like this
If you do what I originally posted the robot will still move in the Z-axis but relative to the base frame, not the tool frame and the motion looks like this, but I thought this was more along what you were looking for originally.
Let me know if you need some more help on this, its taken me quite a lot of playing around to really understand what is happening with this and how to get the robot to respond the way that you really want it to at times
Matt