This is to cover the electronics which live outside the main controller case.
An Omron 2000 line encoder will be used for spindle index. This will be driven by a timing belt from the spindle itself with 1:1 gearing. This will supply accurate spindle position for threading. It connects to the DB9 connector on the Acorn board.
Omron proximity sensors will be used for homing. These are much more accurate than mechanical switches. They are NO switches, but the software can be configured that way. NC is best in case of a broken wire, but these don't work that way. They connect to the Acorn input terminals. I added aircraft plugs to make it easy to disconnect these. I wired one plug for each axis and they share a common input.
I put panel mount sockets on the front of the control box for limits and homing. They work with 24v same as Acorn board. Worked perfectly for first test!