Re: [CAD_CAM_EDM_DRO] Newbie questions???????

Mike,

Thanks for the info on optoisolation! Sounds like that is a must have!

Also sounds like the e-stop wired in through the breakout board would be a good safety feature. My main concern is stopping the table motion w/o relying on software.

Thanks,

Jack

Michael Fagan <woodworker88@...> wrote:
Optoisolation is for the protection of the computer, not the mill. It
prevents voltage and current spikes from travelling back up the parallel
port and frying the computer's circuits. It will also reduce the inevitable
noise and crosstalk that will come from your motor wiring, and therefore
prevent things like your estop from tripping randomly due to noise.

About the E-Stop, there are a couple of ways to go. Hooking it to an
optoisolated parallel port pin and doing it in software is the "elegant"
way, so it will trip Mach 3's own e-stop function. However, unless you are
using Mach 3 for spindle control as well, you will be left with no table
movement but the spindle will still be running. On my CNC Taig running
EMC2, I connected my E-Stop button directly to the control side of a large
(10 amps at 220 volts=20 amps at 110 volts) solid state relay. The power
side of the SSR is connected to a duplex outlet, into which are plugged in
my spindle motor and the 24V DC power supply for the Xylotex drive. I
figure if the situation is serious enough to require an E-Stop, I don't care
if I lose my coordinates, I just want to shut everything down. Eventually,
the same SSR will be rewired for just the spindle motor and controlled by
EMC2 through the parallel port, as will the E-Stop, and it will have the
same effect. This is waiting for Rev2 (this summer most likely).

On Jan 3, 2008 7:46 AM, Jack Mc Kie <freshwatermodels@...> wrote:

> I have started to retrofit my X2 mini-mill using a Xylotex 3 axis
> controller. I plan on using Mach III.
>
> #1 Does Mach III support 2 axis use allowing manual control of the Z
> axis? I have used 2 axis prototrac retrofit on a bridgeport and want
> to operate in similar mode.
>
> #2 I want to add an "emergency" (aw sh__) button to the machine. I am
> also unclear as to the function of "opto-isolation". I am thinking of
> adding a opto-isolated breakout board from homeshop cnc. Will this
> break-out board allow for a very simple set up of an emergency
> switch??? Does the opto-isolation merely reduce "noise" or does it
> protect the computer also???
>
> Any assistance/insight on these would be much appreciated.
>
> Thanks,
>
> Jack
>
>
>

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