The ZAY7045 I have has an interesting "feature".
- To start: Re-arm the "E-STOP", switch it to "Drilling/Milling" and press the "Start" button (spindle turns clockwise)
- To stop: Switch it to "Stop" or press the "E-STOP" (spindle stops)
- To restart: Re-switch to "Drilling/Milling" and/or re-arm the "E-STOP", and then press the "Start" button again (seems a little redundant).
- To start: Switch it to "Tapping" and press the "Start" button (spindle turns clockwise).
- To reverse out: Lower the quill until it triggers the bottom switch (spindle suddenly turns counter-clockwise).
- To stop: Raise the quill until it triggers the top switch (spindle stops).
- To restart: Press the "Start" button (spindle turns clockwise).
I can see that if you were tapping at the same Z height all day, that this could be a handy option. But the setup to get the quill switch to engage at the right point would be far too fiddly for small jobs.
This is achieved with 1 switch (SPDT centre off), 2 micro-switches (SPDT), 2 buttons (1 NO & 1 NC) and 2 relays (with 5 NO & 1 NC each).
So, what's wrong with current controls?
The tapping feature was of little use, and will be of less with the CNC conversion.
The spindle start is onerous, requiring switching and start button.
Spindle stop is uncomfortable (flicking around a flimsy switch).
It didn't allow a manual way to start the spindle counter clockwise.
The E-STOP doesn't stop CNC servo movement.
- The spindle doesn't start and stop under CNC control.
What's the answer?
Change the spindle switch to CNC-Off-On
Create a new independent E-STOP line that cuts power to the spindle and servos, and informs the PC on E-STOP button or axis limits.