help with boards

[mocnc]

Ok please bar with me, I know how to build things using wood/metal and so on, but electronics is a bit new to me. I've been to http://webpages.charter.net/pminmo/cncelectronics.htm , and he shows schematics of controlers(interface) and motor drives. I seen boards that are complete all in one, guess the motor drives are on the main board. Now what advantage is it to have an interface board with motor drive boards as to one board that does it all? Also, please once again forgive my ignorance but what are the differances between bipolar boards and unipolar boards? I am almost done building my cnc and am looking at the controler end of things. I presently have 3 stepper motors "sanyo denki 3.5vdc, 1.5a, 1.8deg/step type 103g7701848" I want to get a set of schematics for pminmo and I am not sure which one. I want it to be a 4 axis unit, because in the future I plan on building my own 4th axis. Does anyone have this schematics in eagle format? Also the complete parts list with a photo of completed boards to kinda guide us newbies thru part placement? Any help would get me going in the right direction. One last thing...THANKS pminmo!! Its not often we get ppl like you giving out free info for the better of the communite! This also goes out to all you that have done the same thing! I WILL contribute in the same way in the near furture

[H500]

If you're new to electronics, then you should try to pick the simplest circuit possible.

You definitely want one of the "Chopper" drives. Otherwise you won't get much performance out of your motors.

Your choice of drives depend on your motors. If they have 4 wires then your only choice is a bipolar drive. If they have 5, 6 or 8 then you can use either.

Bipolar cost more, but can give you 40% more torque with the same motor. The motor you're using seems to be about the same size as mine, (which is rather weak) so you probably want a bipolar drive.

The most cost effective bipolar design I'm aware of, is the a3977 board on Phil's site. But you will need to have the board done professionally, because the chip is so small you won't be able to do it at home.

So that narrows your choice down.

[pminmo]

mocnc,
Ask yourself what you are trying to accomplish, do you want to become familiar with electronics, or taking the satifaction of DIY. If not then buy a board like a xylotex or hobbycnc. The few bucks you save doing your own, probably isn't worth the hassle.

Hobbycnc or Xylotex all in one boards (xylotex does have a single axis driver) are not modular in nature. If you decide you need a stronger stepper on one axis than the all in one can provide, you have to do some improvising. Essentially when the driver and the computer interface are on different modules, you have some fleability. For example you could use my 4 axis board with 2 axis of unipolar drivers, a 3rd of a bipolar driver, and a fourth a servo driver (if the servo driver emulates a stepper driver)
Or you could build two axis and use a Gecko Stepper driver on one.

There is one all in one board on my website, that is tachus42's 3 axis board. And there is a companion chopper board.

Several of the boards have documents that include a part placement layout such as:
http://webpages.charter.net/pminmo/osunidata.pdf

In general a bipolar stepper can be about 40% stonger than a unipolar.

What eagle files do you need?

Phil

[mocnc]

thanks,I kinda got an idea now. But I seen boards on Hobby cnc and other places that can be for a diy. Is there a board that someone can recommend that a diy can build. I thought phil's boards were for diy, guess I was wrong. I am looking to try and build from scratch myself. I know if may be a foolish thing to do, but I would love to learn how to build a board (both interface/motor drive or the one board does it all system). Does anyone out there have the schamtics or is this just a dream of a diy'r ? Also you said my motors are rather weak, how can I figure the strength in them? do I need bigger ones to drive my 1/20 drive screw, thats has the x axis-40" and y axis-"15 and the z axis-3"

[mocnc]

wow that was fast phil lol I just typed my first responce and then there was yours lol , I guess what I am looking for is a way to run 4 axis. I now liking the bipolar cause of the 40% more torque and with my weak stepper motors that could be a blessing. I want to try and build it myself, not engineer the whole thing but build it from scratch. So I guess what I am asking is which one? Which interface do I get the schematics for and which motor drive boards? For the motor drives I would love to have one of each bipolar drive, unipolar driver and a servo driver. The last 2 are for future use only if my new design calls for it. I have the eagle light and I can't seem to do much with the size limitations of it. Does anyone know where I can get an older version that is complete? But then again if I have the schematics with the actual size the should be I can etch them myself

[pminmo]

Precisly what my website is for, those who want to DIY. Bipolar, use 3 L297-298 boards with the four axis interface board. All of the boards on my site were done in the Eagle light version. You would be surprised how much you can get in that small area, especially when using both sides and surface mounted parts.
The eagle files are zipped here for the L297-8:

http://webpages.charter.net/pminmo/L297-8.zip
4 axis interface:

http://webpages.charter.net/pminmo/4axisbob.zip

Phil

[mocnc]

Hey thanks Phil,

Are they both single sided? for double sided? and is there a parts list for this boards with an actual picture to show what these boards should look like when they are done lol. I guess for a diy its nice to see the parts and where they go with no guessing. I also from cnczone got a pictural on how to make my own boards, does anyone of other methods? Has anyone made g-codes for these boards or any other boards? Is it worth it? Or is the old way the best? Will this work with my 6 wire step motors now? Also how do I determine which wire of my stepper motors go where? I have white, orange, blue, yellow, red, black. I know where the red and black go what about the other 4?

[pminmo]

both are single sided etched. Both have links to copper for toner transfer and parts layouts on my site. The interface board has a document to support it.

Phil

[mocnc]

Thanks once again phil, please bare with me, I think I got the board layout for the l297-8, I hope. Could you post the board layout for the copper for toner transfer and parts layouts for both? I hope I am not being a pest, I just want to make sure I am getting the right things. Also the actual sizes of the boards, what are they? Is the l297-8 8.5 inches by 11 inches? What is the 4th axis interface board? Last but not least, I tried looking for the auto route in eagle light and I couldn't find it. Does it have it in the eagle light? I wanted to run and make the copper layout so I could try and fabricate the boards. Oops forgot one more thing, have you ever or do you know of anyone who has theses boards written out in g-code for cnc/milling? Is that something way to imposible to do? If it has been done where could I get the g-code to cut these boards out of copper instead of using toner method.

[pminmo]

mocnc,
You really don't need the eagle files: To make the pcb from my website:
http://webpages.charter.net/pminmo/L297_8copper.pdf is the copper for toner transfer for the l297-8.
To load the pcb use the layout from my website:
http://webpages.charter.net/pminmo/L297_8board.pdf
This is a little more tricky, the components you need by value are on the schematic on my website:
http://webpages.charter.net/pminmo/L297_8schematic.pdf
http://webpages.charter.net/pminmo/L297-8.htm
You will need three of those boards for a three axis machine.
The physical size of the board is 3.9 x 2.1 inches.

[MrBean]

Originally Posted by mocnc Oops forgot one more thing, have you ever or do you know of anyone who has theses boards written out in g-code for cnc/milling?

If you have access to the eagle files you can have gcode for milling, generated using the appropriate ULP script.

Regards Terry.....

[kfong]

Here are two proven and very reliable designs. The pcb is professionally produced.
http://www.embeddedtronics.com/microstep.html
http://www.embeddedtronics.com/microsteppld.html
Both will work fine, the pld version is faster but you will need a very fast PC to make use of it.

The design is based on the National Semiconductor LMD18245 3amp 55volt full bridge motor driver. This is a very rugged chip capable of 6amp surges and has 12amp burst rating.

Kin

http://www.embeddedtronics.com/