I have this Sieg SX4 mill https://www.paulimot.de/fraesmaschinen/sx4
Currently, spindle motor control works like this:
There is a potentiometer for spindle speed.
You enable the drive by unlocking the E-stop (wait a few seconds for the controller to boot) and start it with the green start button (so far so good).
There is no stop button. You hit the E-stop instead (strange - well, they saved the more or less duplicate stop button)
Bonus: Tapping mode. There is a toggle switch for that, in tapping mode, speed is 1/2 (50 rpm min) and the green buttons on the three quill handles reverse direction. Neat for power tapping.
I am not sure, but I think it would be nice if I could retain the tapping mode and also keep is halfway usable for manual drilling. After all, it has a quill with depth gauge and fine feed (all of which is unnecessary/locked in CNC control). Any thoughts? Obviously, I'd better have separate machines for CNC and manual operation, but this is a home shop and I have neither space nor budget for two machines.
Now for the simpler part: Could I generate the required control signals for the spindle controller from the Acorn board?
Speed should be easy, I assume the potentiometer generates 0-3 or 0-5 V, which could be wired to the Acorn speed 0-10V output (no isolation though).
On-off is a bit more tricky. There is no "run" input. Instead, when power is on, you give a start pulse (green button), but then it runs until power is cut (e-stop). After powering, it needs a few seconds before you can start it again.
Assuming I have two contactors - one for the axis servos and one for the spindle, I could use that for stopping the spindle. There are two possible ways to handle the "stop" mode:
1 - for starting the spindle, enable the spindle power (via contactor), wait 3 s, then apply a pulse to the start button. To stop the spindle, disable the contactor
2 - always have the spindle contactor enabled. For starting the spindle, give start pulse. For stopping, disable and after (?) 1 s re-enable the spindle. Earliest next spindle start can be in 3 s.
Nothing crazy, but I am not sure if those somewhat unconventional sequence can be generated by the Acorn board.
Thanks, Martin