DIY Interface and stepper drivers

[hansenmick]

Ok....I've been looking over these forums for quite some time and still have not found an answer to my question. I would like to build my own interface and driver cards. I eventually plan on having 4 or 5 axis, and would like to have it connect to my machine via USB or Ethernet. I know the Grex does that, but trying to convince my wife to drop $200+ for ONE part is the battle. I just got my first three steppers today (YAY!!!) and this is what they are:
Slo-Syn KML092F-102's. 4-wire, 1.4vdc, and 7.0A. Honestly, I am not concerned with how big (physically) the board(s) will end up being. I can't find any SOLID data on the electrical specs of these motors. The closest I have found is this:
http://www.mcsupplyco.com/uploads/pr...ProductID=1214
Seeing as I have never seen one of these machines running, just how much difference is there between the interface types? (eg:Serial, Parallel, USB, or Ethernet)

I am assuming that I will be running these motors at around 36vdc....maybe higher?

ANY help and/or links would be GREATLY appreciated!!!

-Mick

[kiwichris]

Those are big steppers, what size of machine are you looking at?

Looking at the controller, if you want to go to ethernet or USB you're going to need some sort of 'smart' interface, not just a simple break out board as is used with parallel port interfaces.. Like the GREX from Gecko or the one from Deskam...

That is going to cost some sort of real money, I'm not aware of an open source interpreter/controller board to do this part of the job, although I may be wrong.

And with 7A steppers you're going to be limited to the available open source driver solutions to stick on the back end of your controller as well.... Most open source solutions are 2.5-3A rated, and I've seen a couple of 5A ones, but the higher power stuff is thin on the ground, and fewer people will be able to assist with experience etc..

If you're building a big machine (As your steppers imply) the cost of the controller and stepper drivers will be academic by the time you add it all up, so you might have to convince the wife that gecko drivers and grex are the way it is!

Good luck with the build, and the wife.

[hansenmick]

Well, the machine I want to eventually have will have a work envelope of 48 x 48 x 12 inches and I plan on being able to machine almost any material I come across (steel, aluminum, plastic, wood, ect...). I already have the X-axis shafts, blocks, and ballscrew (60+" parts I got for free). As for the limited drivers, what exactly is the limiting factor? I hate being electronics ignorant!!! Actually, thinking twice about it, $200 for the Grex101 isn't bad considering everything it does. Am I correct in that I need a Bipolar driver? If I were to go with Gekos, I am thinking the G203v would be my best choice...hmmmm....$150x4.......ouch......

[kiwichris]

That is a serious machine you're planning on cutting steel on a 48"x48" work area...

By limited, I meant that you're limited to the number of DIY options available, not that the drivers are limited in some way.

Yes, with 4 wire steppers they will be bipolar. If you're looking for a 'build your own' bipolar design to get full power out of those steppers you're not going to find any easy to build circuits, if any.

If you're really keen on doing the electronics yourself there are some clever people on this site who could help, but it's not really a beginner electronics project to produce a bipolar stepper driver of that size.

If it were me building a machine that large myself, I'd be saving my pennies and going with the Gecko's...

Disclaimer: I have never gecok drivers, but from accounts on here and other sites, and the professional and helpful way that Mariss aquits himself and his product on this site I'd say you couldn't go wrong with them. (Mariss is the owner of Gecko I think, or at least he's the electronics geek who designs their gear)

Cheers, Me.

[pminmo]

You need to look at the software you want to run and see what kind of interface it supports. There are a couple of DIY USB interfaces, but they are pretty much captive to their own software.

[hansenmick]

I must apologize...I tend to 'waffle' a bit sometimes....

Now, I'm not going to be dropping a slab-o-steel on the table that's 48x48x12 and expecting to hold +/- .001!!!! I have been thinking about it alot lately, and I think I will just go with all Gekos. The only parts I actually have on hand right now are the 3 steppers and the rails and 'screw for my X-Axis....I still have ALOT of parts to get!!! And seeing as how I got those parts for free, that in itself justifies spending the $$$ on the G101 and at least one G203v. Also, everything for the Geckos is designed, engineered, built, and, best of all, plug-and-play. Heck....by the time I built the third or fourth driver and or interface, I would probably have spent the same $$$!!!

I have actually been kicking a couple of ideas around as for my spindle:
1)A high-powered 1/2" router directly. (I could always design and build my own uber-spindle!!! )
2)A high-powered 1/2" router driving a drill press spindle via timing belts. Of course, I would be dropping the RPM down to the sub-10k RPM range if I were to go this route. I like the sound of this one because I would be able to get collets for darn near any cutter I could want.



-Mick

[pminmo]

Buying Gecko's is money well spent.

[hansenmick]

Something else I just realized tonight is that the company I work for recently purchased a 20' horizontal boring mill.........I think I will be using that for some of my parts.......

[hansenmick]

Ooooops.....so, since I have decided to go with Geckos, what voltage and amperage power supply should I get? Any examples?

-Mick

[eded59]

If you look here http://www.danahermotion.com/documen...uct_cat_id=549 They show a KM92F13 with different voltage and amperage and the resulting torque curves, if you open the catalog there are some graphs with this info..

[hansenmick]

If you look here http://www.danahermotion.com/documen...uct_cat_id=549 They show a KM92F13 with different voltage and amperage and the resulting torque curves, if you open the catalog there are some graphs with this info..

Ok...so, according to the graphs, I either get 700 oz-in with 72vdc @ 8A, or 600 oz-in with 170vdc @ 6A, or a meager 3oo or 400 oz-in with 36vdc @ 2.5A or 3.5A, respectively. What I get from this info:

If I build my own drivers and interface and drop down to 3-400 oz-in, OR...
Run 72vdc with the Gekos and get my 700 oz-in.

Cheap at the beginning and less powerful...or save my pennies...? As I said before, I still have two more axis' worth of hardware to get before any more REAL planning can take place.