Re: PWM vs Constant current

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jarrett & Heidi Johnson
<hjjohnson@s...> wrote:

>
> Alan, thanks for taking the time. Don't worry, I'm not offended by

someone

> waving a BS flag , I'd rather learn this now vs, later after I've

spent the

> $$.
>
> I had settled on a cnc4pc break out board and a charge pump run through
> Gecko 202's and a 34 size motors but this kind of side-tracked me. I'm
> looking to build the simplest [ as far as figuring out electronics]

system

> by purchaseing all the pre-made boards and what not that I can off the
> shelf. Yet I didn't want to buy a complete off the shelf system as

that was

> to big of a jump in price.. somewhere in between was the plan.

I've been

> reading cnc sites and posts for 2 weeks straight [ at least 5 hrs

per night

> as well as weekends and coffee breaks @ work ] so.. I'm getting a

grasp but

> still missing some key points which will hopefully be filled in over

time.

> I'm wondering about the Rex board by Gecko, what does that do vs, a
> break-out board? Any recommendations for breakout boards that work

great w/

> Mach 3? I've got many more questions but I'll leave those for later

for

> now I'm off the the yahoo file section for more reading!
>
> Thanks
> Jarrett Johnson

Hi Jarrett,

the Gecko REX is not a driver, it is an interface board.

Check the specs on your breakout board, it will be 3 or 4 motor
outputs, the REX can do 6.

Also the unit accepts quadrature inputs so it connects the encoders to
the board.

In addition, a parallel port can only to 8 outs for 4 motors (one step
and one dir each) and another 4 outputs and then 5 inputs.

the REX can do 6 motors and 16 additional outputs and 22 addition inputs.

In addition it has 4 analogue ins and 4 analogue outs

and connects via USB or eithernet.

So, what that would make that card out to be is the interface for a
very high end platform. Everything is already in there so there are
no additional cards to be for another motor or more I/O's.

At $208 it is only about $50 more than a high end parallel port card.

I would expect to see those parallel port cards on e-bay soon as the
guys who spend the $$ want the best.

All I see that is missing is a 7th encoder input. one for the pendant
jog unit. but, I would bet that can be handled quite simply.

Dave