Electronics for New Machine + Chinese Spindle + VFD

[Neale]

Excellent. I like your idea that sounds better and much more accurate.
What confused me was this diagram in the KK01 manual showing that I might need to put extra resistors in the driver wiring as well if I was running 24v through the KK01.
That put me off.

The resistors are to limit the current going into the opto-isolators at the front end of the KK01. In crude terms, these opto-isolators are designed to accept 5V signals so with a higher voltage, you need to limit the input current to a safe value. It's a very straightforward and common thing to do. Those resistors will cost you about 3p each from your local Maplin so no exotic components needed!
The KK01 needs 5V in any case; the 24V supply is just to feed the limit switches. As Jazz says, the KK01 will still give a 5V output to go to the drives.