text: <s>[INST] Questions regarding the MAPC master lock position and cam lock position Hi, I'm setting up a motion axis with MAPC motion instruction. We are programming a derrick crane's main boom hoist axis to maintain a constant horizontal movement speed. The virtual/master axis is the boom reach radius, and the physical/slave axis is the boom hoist motor. The picture below illustrates what the setup looks like. I have run a couple of tests to see how it works, but the motion axis seems to be struggling to follow the actual cam profile I entered in the Cam Editor window. I believe the issue is my lack of understanding of the master lock position and cam lock position. I read a tech note in Rockwell's knowledge base, but I still cannot relate that to my actual setup. So any insight would be greatly appreciated. Other parameters are the start slope and end slope in the cam editor window. What is the purpose of these two parameters? how do they impact the cam profile? Thanks! [/INST] EDIT: linkified for convenience -FL Zhang, The key to making this work is have a CAM... which is the relationship between the input/output which are unitless. When you get into xy or polar, then you might look at translation of coordinate systems. Logix has some built-in translations for coordinate systems... This one might work for your application where J3 is always vertical. Prior these defined geometries we would just write the vector loop equations. This is typically two equations with 2 unknowns so you can create a substitution and solve for the position equation in terms of the input (actuator). You can Google Vector Loop Equation... here are some results: https://www.youtube.com/watch?v=1-HItSmJlc4 https://www.youtube.com/watch?v=PiMwPjlV0jw&list=PLTMo3nrl2KWYntt5n6DCA28B-CMqbl9S2&index=4 \\n </s>