New and need your help Please (driver board)

[Oldmanandhistoy]

Hi all
This is my first post on this site and before I go on I would like to say “thanks to every one on here for making this the excellent forum which it is”. Not sure if I can contribute anything at this time but hopefully will in the future (qualified wood machinist for 18 years, cnc building beginner and electronics dummy).
With the help of other posts and a Hobbycnc plan I have nearly completed building the mechanics of a MDF cnc router (no problem so far thanks to this forum).
Now it comes to the electronics of my project my head has began to spin. So much info out there, so many choices and many hours of reading really need some help please.
I made the big mistake of buying a so called part built Hobbycnc kit from ebay (which got me started in the first place). What I got was this.
Plans to built the router, 3 different lengths of trapezoidal 3mm pitch with anti backlash nuts, 2 lengths or 12mm shaft, 3 Shinano Kenshi unipolar 6 wire stepper motors (rated 5.1V, 1A, 4 phase at 5.1 OHMS per phase and holding torque 59.7 OZ-IN.MIN), 24V 10A psu, very old by the look of it Hobbycnc 3 axis board and 1 or 2 other bits and bobs.
I’ve scraped the board and am now looking for something to replace it. After a lot of reading this is what I’m thinking. Buying a Xylotex XS-3525/8S-3 3 axis bipolar drive board.

Will this board drive my steppers (if not will buy some bipolar steppers to replace them).Hoping to work with MDF and Ply?


Other than hardware (cables, switches and my PC) will I need any other boards or electronic components for this to work?

Thank you to anyone who helps in advance any help will be very much appreciated.
Really hope I put this in the right place ) .

[H500]

Since your motors are unipolar, you need to get a unipolar driver. 59 0z-in is a bit weak. Automation direct has 250 oz-in (or so) bipolar steppers for $40.

[Oldmanandhistoy]

Thanks for that H500. The reason I asked about the unipolar motors is because in the data sheet that comes with the board it mentions unipolar motor set up and was wondering how the steppers I have would work with that board. Would I be right in thinking I would loose power using a bipolar drive?
If the motors are no good for my router with xylotex driver board (think I made a mistake with torque and are 85OZ-IN not 59.7 by the way sorry) will I need anything else other than bipolar motors?
One other thing I’m in the UK so if anyone knows of good sources for new stepper motors over here would appreciate it.

[zoltan]

H500,

I have seen at certain moment some posts about a microstepping controller designed/built by you. Which is the development status of it? Have you finished it? Did it work? If the controller is working now, and as I remember it seemed to be a cheap solution and based on parts that I can find here in Romania, can you share with us the design and the source code?

[H500]

Oldmanandhistoy: Sorry, I make a mistake. A bipolar drive will have no problem driving unipolar motors if you wire them up properly. The torque will be same as a unipolar drive.

Your motors are a bit weak, but I think they will be useable if you don't need speed. You can always upgrade them later. I'm using ~130 in-oz motors on a dovetail type x-y table and I think it's underpowered.

Just remember that the xylotex is limited to about 2.5 amps, so if your motors need more, you won't be able to get full power out of them. I believe xylotex offer motors that are well sized for their drives.

[H500]

Zoltan, I done 2 microstepping controllers. One is based on the allegro 3977. Another is based on the national lmd18245.

The 3977 is the cheapest and simplest and don't need any programming. The 18245 is quite expensive, but is more not as easy to kill and handles more power.

If you're interested in the 3977, there's an open source design availble. If you prefer the 18245, take a look at PICSTEP or the board from EAS. Both are good open source drivers.

I was also experimenting with an AVR based controller. It's not microstepping, so I haven't been using it on my mill. It is theoretically not hard to change it to microstepping and I think someone else was looking into it. This board can handle much bigger motors than the others, so I might work on it again in the future.

The source code has been posted, but I can email it if you can't find it.

[zoltan]

Thank you for answer. I was referring to AVR, and i was thinking that it is a microstepping controller. Have you done a final design of it, or it is still on development. Could you make the development of source to microstepping? Iwould be interested in your design as I have a problem finding out the parts, but I found out four AVRs.

[Oldmanandhistoy]

Thanks again H500.
That clears up my thinking about loosing torque with a bipolar drive. I do believe my motors are probably too weak for what I have in mind but hoped they might run ok while I find some bipolar motors (still looking in UK for a supplier of new motors at a reasonable price).
The other question I have is do I need any thing else other than the driver board and what I mentioned above?

(Trying not to mention hijacking ) )

[H500]

Zoltan: The circuit was experimental, so I wouldn't recommend anyone build it unless they are able to do some design modifications. A microstepping version will need a slightly different circuit.

[H500]

Oldmanandhistoy: I think you might also need an opto-isolated breakout board to connect your PC's parallel port to the driver. I did not use one on my design. I just cut one end off a printer cable and connected direct to my driver. This needs to be done with care since wiring mistakes could fry the PC.

[mdreitzusa]

Oldmanandhistoy,
if your motors only need 1 amp why not use a ucn5804 based driver.
nelnick has them for 4.79 ea. you will need one per axis.but they give you the wiring diagram,and it is very easy to put together. i have one on my machine and it work just fine.it has 1 or 2 phase and 1/2 step built in.you can check it to see if it meets your needs at http://www.nelnick.com/nelniech.html
hope this helps

[Oldmanandhistoy]

Originally Posted by H500 Oldmanandhistoy: I think you might also need an opto-isolated breakout board to connect your PC's parallel port to the driver. I did not use one on my design. I just cut one end off a printer cable and connected direct to my driver. This needs to be done with care since wiring mistakes could fry the PC.

Have looked at opto-isolation and seen it mentioned many times on this site. Would it be a mistake for me not to use one? Do off the shelf printers have these or are they just for people like me (likely to make a mistake with wiring)?
Is there a case for opto-isolation to protect the PC once every thing is wired up correctly and up and running?
One other thing I guess as you didn’t mention them I don’t need current limiting resisters with this drive?
Just so you know H500 I very much appreciate your time and input ) .


Mdreitzusa
Thanks for your reply )
The reason I’m looking at the Xylotex board is I plane to upgrade the stepper motors in the future to bipolar. As far as I can work out bipolar are superior to unipolar, please correct me if I am wrong.