Re: [CAD_CAM_EDM_DRO] Re: Safe Spindle Control

Jymmm wrote:

>Hi Larry,
>
>Do you have a url, pic, schematic, wire diagram for this by chance?
>
>
>To the group:
>I've posted this question in a couple of places and I get very little
>response. I know it's a valid question, but is the lack of response due to
>technical "We just dont know" or what?
>
>

I think the problem is that the answer depends largely on what hardware
you have, and what you consider to be "safe". It also depends on what
you want to prevent when changing tools. Preventing the spindle from
turning on is easy. Do you want to inhibit axis motion as well?
(possibly) Do you need to maintain position while changing tools?
(yes) Do you want the software to know that you're changing tools?
(probably) Do you want the software to be able to recover if you forget
to reset the spindle disable switch after changing the tool? (maybe)

The suggestion of using a physical switch near the spindle, which is in
the coil loop for the contactor that runs the spindle, is probably your
best bet. You can add a software "safety" to this, by putting a second
set of contacts on the switch, and using those as an external "spindle
disabled" signal for the controller software.

>I understand that Mach has some pulse train, but I'd rather have something
>within the hardware that will keep me safe rather than the computer itself.
>No magical eletronics/electrical engineer types out there with some
>ideas/suggestions by chance?
>
>

Hardware is definitely the way to go, if you're looking for maximum
safety. But only safe hardware ;)

>Thanks,
>Jim...
>
>

- Steve