Is the '2nd version schematic' different than the version you have on your website or are you just refering to a different copper scheme? Also which resistor are you refering too?Originally Posted by pminmo
Thanks.
Chris
I've verified that the 2nd version of this board is up and running. (although there is one resistor that needs to be left off) I'm not intereseted in making a profit, just helping some DIY'ers. I've asked for a quote on buying additional blank boards. These are double sided, plated through hole, silk screen with solder mask boards. Warning It does take good soldering skills, a fine soldering iron, and good eyesite to solder the 44 pin surface mount part. Pics here, but the blank board picture doesn't do the silkscreen justice.
http://webpages.charter.net/pminmo/3977.jpg
http://webpages.charter.net/pminmo/proto3977.jpg
I suspect the cost to be $8 or a little under per board. i.e. $24 or less for 3 plus postage. If there is any interest send me a private message, or an email via the zone. I don't think I want to hassle with mailing outside of the US, as I have not done it before.
Phil
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Last edited by cncadmin; 11-15-2004 at 10:15 PM.
Is the '2nd version schematic' different than the version you have on your website or are you just refering to a different copper scheme? Also which resistor are you refering too?Originally Posted by pminmo
Thanks.
Chris
Yep Phil put me down for 3. Making the board was my biggest hinderance in trying out your work. I will PM you my details.
Thanks mate, your continued work is greatly appreciated, and highly noticed in this forum.
Being outside the square !!!
OCNC (Chris)
Same version, R5 is wired wrong. It's not really necessary as all it does is hold the DIR line high if nothing is connected. But the line that is wired to r1 and c17 should have gone to JP1 pin 3 directly. Rather than fix it, its just as good to leave it off, nbd.
Phil
I follow you regarding R5 but it looks to me like what you're calling R1 and C17 is actually R18 and C17. The line that's wired to R18 and C17 is coming from pin 1 of the 40106N. Is this the line that you're saying should go directly to pin 3 on JP-1? Is this also nbd or did you re-route it in 'Version 2' of your board?Originally Posted by pminmo
Chris
Chris,
Your correct, it is R18 and c17. I misread my own schematic. Basically the intent was an rc filter made up of 10K and 470pf, with a 10K pullup. If you were to delete the connection of r5 ot r18,c17, and move that r5 connection to to JP1 pin 3 was my original intent. Like I said it's nbd with it out.
Phil
Unfortunately due to a number of reasons I'm withdrawing my offer to make a batch buy. Fundamentally it just got unmanagable.
Sorry,
Phil
How to I know what driver board to use with my motors? Ideally I would like a driver board kit that can be assembled but which should I choose to go with my motors? The motor specs are StepSyn 103h7123-1742, DC 4A and I'm not sure of the volts.
Any adivce is appreciated.
Suggest you do a google search on StepSyn and get all the motor data. unipolar, bipolar, coil current, coil voltage.....
Phil
Originally Posted by pminmo
wow bummer... was looking forward to them
Does anyone know where to get a board for the A3977? I am trying to get into the CNC hobby with out going for broke. Would using the A3977 be the most economical way to drive bipolar motors?
Kevin
Any1 has any power supply unit contruction diagram that cater the sufficient voltage/current for A3977 driver circuit? (all the 3 axis)
I am abit confused when searching thru the posts for building a PSU, terms like toroidal transformer and even some1 talked about PC AT power supply put in Series and things like that. But i couldnt find a well complete circuit for our lil need....
I m looking at 2.5A @ 30V or less for driving my PK268... is my math correct here:
Bipolar Series - 1 motor -> 5.0A and "real" amperage is 1/3 of it, which is around 1.67A
Then, all the 3 motors totaled up about 5.0A current needed!??
THanks!
While not as good as a torrid, but a much less expensive transformer:
http://www.allelectronics.com/cgi-bi...245&type=store
In conjunction with a full wave bridge recifier:
http://www.allelectronics.com/cgi-bi...352&type=store
Plus a big filter capacitor Makes a fairly inexpensive power supply. You do need to look at the output voltage though as it's really close to 35V unloaded. In theory loaded s/b 32.5Vdc.
Phil
Thanks phil..
How big is a cap needed? 4000uF?
I've found a 35A 800V rectifier here cheap, is it okie?
sorry for long winded...
I've oso found 4700uF 200V multilayer ceramic cap, is it ok too?
Greater than 40 vdc, 4700uf is a little on the light side. Electrolitic, I'd suggest 15,000uf down to 10,000uf.
Phil
Heres some 10 amp transformers that i use that work good for 17.99 if your looking for more amps
http://www.mpja.com/productview.asp?product=7846+TR
Thanks Guys!
I've found this Toroidal of 25V 5A quite cheap locally.
http://my.farnell.com/jsp/endecaSear...=3068948&N=401
I go for toroidal since Farnell M'sia is selling the normal box-like transformer at higher price of similar ratings, that's strange....
So i assume there'll be a few volts drop at bridge rectifier and the output 25V * 1.4142 = 35.36V will not harm my A3977, does that sound rite?
As for the rectifier, i have found a 200V (reverse voltage) and 25A (forward current) at farnell too:
http://my.farnell.com/jsp/endecaSear...KU=5398812&N=0
Then, the big cap i've found is a very cheap 63V 15,000uF of 20% (snap-in terminal):
http://my.farnell.com/jsp/endecaSear...KU=6466758&N=0
I oso got 5A quick blow fuse after the cap and before the driver pcb. And the 1A fuse after mainline and before transformer.
I've seen a circuit from xylotex discussion group where they have EMI Filter bfore tranformer, is it necessary too?
BEFORE I KILL MYSELF, what r the safety issues I have to take PRECAUTION before entering into this hazardous area of electronic/electrical???? Like wearing latex glove, discharginig capacitors etc........ this is definitely very important for all here!
Thanks for reading....
Andy
andyew,
Looks like your on the right path. Your PS voltage will probably be higher unloaded. The cheap way to drop some voltage would be to add a couple of 5A diodes in series with the plus lead.
Phil
Thanks Phil! i've oredi placed the order.. it's paid by university.. haha