Re: [CAD_CAM_EDM_DRO] Re: How to convert a Grizzly 1006 Mill to CNC

At 05:36 PM 10/19/2007, you wrote:

>Now you had me worried, it sound like I will have a problem there to.

No problem, just a fact of life. There will be a minuscule delay
between the ports outputs, but you will never see it.

>But what about all the merchandish sold, it never says anything
>about having 2 or more parallel port for running one 4 axis router.

Let's start by assuming one enable for all motors, there are at least
two signals (step and direction) for each driver. Four need eight
plus one signal. If there is absolutely no spindle control, you can
get away with one parallel port (8 data bits and one control bit) for
motor control, since there are six additional input bits on the port,
E-stop and five switch inputs.

Now, one asks, how so I have 8 limit switches and 3 home switches go
into 5 inputs? All three home switches can be on one input. All "X"
limit switches go to another, "Y", "Z" and "A" each go to one. BUT
when at a limit, you have no way to tell if you at the plus or minus limit.

>I am not planning on having a computer controlled spindle, but I do
>like to know where home is on every axis.

Well, that is a problem. Given a controlled spindle, touching with
power off is pretty simple. It only requires a "probe" signal. For
a running spindle, probing is much more tricky. Photoelectric sounds
like the best choice.

>How do you recommed to go about this?

Given your choices, a single parallel port will just work. You won't
have much left over. Two will work better. If you want spindle
control and/or separate sense switches, two ports will be mandatory.

Or you could go with something like this http://www.usbcnc.com/ which
is pretty cool in it's own right.

David G. LeVine
Nashua, NH 03060