Recommended way to implement spindle enable conditions?

Hi everyone,I'd like to add some safety conditions for enabling the spindle on my lathe.The spindle should only be allowed to start if all required conditions are met, for example:

• The auxiliary drives are enabled.
• The chuck is clamped (clamping pressure is present).
• (I may add more conditions later.)

My first idea was to simply combine these signals with one or morecomponents and use the result as the spindle enable signal.Something along the lines of:Is this the usual way to implement this in LinuxCNC, or is there a better or more recommended approach?How have you implemented spindle interlocks on your machines?Thanks!

If you have a long string of conditional pins/signals, the logic component is a little less messy in HAL than a bunch of nested/sequential and2 components.

linuxcnc.org/docs/stable/html/man/man9/logic.9.html

If you just want some interlocks to prohibit starting the spindle while chuck is open, or opening the chuck while spindle is turning, and2 or logic work fine.

However, I prefer using Classic Ladder for my spindle(s) and drawbar(s).  My lathe has two spindles, each with a pneumatic drawbar.  I control the drawbars with either physical buttons OR via M-codes.  M-code control is necessary for automated bar-feed operations.

I also want to be able to open the collet closer while the spindle is running, although at a low maximum speed.  Also need ability to orient spindle while the closer is open (hex/square stock).

Given the complexity of my particular config, I found ladder be be more intuitive and easier to configure (and test).

There is also:
spindle.N.inhibit - (bit, in) When this bit is TRUE, the spindle speed is set to 0.

I used lut5 to check for various conditions.

Here is my HAL on Github:  github.com/shallerbach/endchen_rack_atc/...3f0/endchen.hal#L124

Lut5 is the best solution, especially when condition is type of "if a=true and b=false".
BTW. Beware situations when your spindle turns off when axis moved. It is more dengerous than continue when something fails.

Thanks for all the suggestions and ideas!
I will give it a try and see how it works out on my machine.