Hey Daryl,
For what I know, it will be a future option to be able to auto square a machine using 4 lim switches. I believe there is a beta capable of doing this, but it’s a use at your own risk one. (Talked about by Chris in this topic)
I can imagine that the introduction of that function might be close and that sienci is already shipping its switch sets including the 4th one. For now, the slb manual onnthe switches is still only hinting towards the feature but warns not to use the 2nd yaxis limit switch port yet.
Found here: