Re: [CAD_CAM_EDM_DRO] Safe Spindle Control

Jim,
A lot depends on your faith in electronic devices.

Personally, I unplug the cord on the router in my CNC mill and lathes
before changing tools. I just don't trust my fingers to an electronic
system that can be turned on by a static zap or stray cosmic ray. The
simplest solution is just to be sure that your computer has booted and
the CNC program is running before you apply power to the cutting system.

It is possible to use a keep alive pulse train (A.K.A charge pump
output) from to enable the power relays, but again, I personally don't
trust such a system to protect myself. My Dad nearly amputated three
fingers on 11/11/05 when he plugged in a router without checking that
the switch was off. It will be a while before he is back in the shop
again.

My $0.02

Dave

Jymmm wrote:

>I will be using a SSR (Solid State Relay) to turn on/off my spindle, wired to
>a SPDT (center off) switch (ON/OFF/AUTO), then to a pin on the parallel port
>(active high).
>
>Now from what I understand the parallel port can act funky during power up or
>reboot (toggling the signals out of the port till stabilized).
>
>I understand Mach has some 8KHz pulse stream (but no idea on how to use
>that), plus I use TurboCNC and EMC once in a while too.
>
>Is there anything that can help resolve the funkiness no matter what the
>controller might be? I'd hate to have a cable come loose (as example) during
>a manual tool change and the spindle startup for a few seconds *OUCH*.
>
>Yes, I could hit the switch to OFF, but the kinda defeats the purpose of it
>at all, and I'd hate to forget to flip the switch back to AUTO and have the
>tool plunge into the material not spinning *CRUNCH*.
>
>Thanks,
>Jim...
>
>