[markcomp77]

external Schottky for a3977

Thero use BYV27... on http://www.students.tut.fi/~kontkant/a3977.php.html

Q13...Use of external Schottky diodes with low Vforward, to clamp the outputs to VBB and ground, will help to reduce the power dissipation in the A3977. ....

Q15...We typically don't recommend a specific diode due to the range of voltages and currents that can be used.

;(

byv27.. uf5400, fr303, sb540, mbr760

what type of diode you recommend ?

[smarbaga]

hello
i c that the 3977copper.zip has a png extension.
do you have this in gerber of tiff format as i cannot read or convert a png file.
or do u have a png converter
thanks

[slp_prlzys]

attached is tiff version of single sided joe's version.
you might want to check it, I cleaned it up a bit
with image editor, but I can assure you it's the
same, I already built a working board with it.

[RC490]

Hi guys,
I am relatively electonicly challenged, but can solder etc. I found this unipolar chopper circuit on the net and am looking for comments on whether this will work. It is baed around the l297/9 chips. I have these chips and are thinking of substituting the fet for IRF540N's. Will this work? or is the circuit incomplete?
Look forward to your input.
BRG
Andy J

[pminmo]

Andy same concept as the L297uni on my website. It just uses the L298 to driver the Mosfets. With logic level mosfets getting so inexpensive and robust, the cost of the L298 VS a 74HC08 (or 74AC08) isn't worth the difference.

[RC490]

Andy same concept as the L297uni on my website. It just uses the L298 to driver the Mosfets. With logic level mosfets getting so inexpensive and robust, the cost of the L298 VS a 74HC08 (or 74AC08) isn't worth the difference.

Thanks for the reply Phil, had a look.
Em, your circuit has diodes in the return lines and the one I have been contemplating hasn't? I presume that this will be ok as is? or would you suggest any improvements?
(I'm pretty skint at present and as I already have the 297's/8's and the rest of the components, would you suggest going ahead and trying it ?).

Please excuse any dumb questions..... I'm sorta trying to learn this on the fly.
Brg.
Andy

[ggg]

Andy same concept as the L297uni on my website. It just uses the L298 to driver the Mosfets. With logic level mosfets getting so inexpensive and robust, the cost of the L298 VS a 74HC08 (or 74AC08) isn't worth the difference.

Phill, better than 74HC08 is 74HC09 for your 297unip. do you think so?

[pminmo]

No it would be worse!

[bobleecnc]

Hi are there any open source bipolar board designs available that are capable of at least 4 amps per phase
I'm also planning on using Mach3 it's not open source but its free for me because my code won't come close to 1,000 lines if I ever get my router finnished ,but I'll probably my Mach3 anyway as I like it . and for the money it's a deal so are there any open source bipolar designs capable of 4 amps per phase that would also work with Mach3

Thanks Bob

[markcomp77]

Hi are there any open source bipolar board designs available that are capable of at least 4 amps per phase
Thanks Bob

yes... bipolar and 4A
and 1/2 step

http://engraving.majosoft.com/html/b...and_L6203.html

or...



I don’t have tested this

link to project: http://www.cnc.info.pl/viewtopic.php?p=16082
and info: http://forum-cnc.pl/viewtopic.php?t=55

[bobleecnc]

Thanks Mark That helps do you know about how much it cost to build it ?
also one more question do you or anybody else know where I can find some specs. on some old vexta ph299-01 motors or would some one have that info to share with me ? particularly interested in both bipolar and unipolar holding torque's ? Thanks again Bob

[markcomp77]

do you know about how much it cost to build it ?

yes... cost in zł
l297 - 11 zł
l6203 - 12 zł
...

1 usd = 3,2 zł

[BackHar]

Does anyone knows a 3 axis board controller avaiable for EMC? The tachus42's it's a good idea but I don't have place for big resistors and isn't avaiable for EMC. Thank's so much.
Haroldo

[pminmo]

bobleecnc,
Eventually, but it's not there yet.

[pminmo]

backhar,
The interface board in conjunction with the individual driver boards are compatable with emc.

[markcomp77]

lpt setup...

[pminmo]

I just added a link to a new 4 axis interface on my website as well as a webpage on an engraver used with the 3977's.

[BackHar]

Thank's for this table.
Pminmo, do you have a schematic of current limiting resistor board for example? Do I use one resistor for each coil?!

[pminmo]

BackHar,
I can't say that I would recommend using a non chopped board. Yes it's cheap, its a good learning tool, it will run machines, but it's not a "performance driver".

[contactirfu]

Hi Phil

Got the PCB's done for the L297 Uni and finding it difficult to trace out the BZW04-48rl, would u suggest something else, also the LM319HVT is not available in the To220 package but in a big ugly steel type thing. how to get thu this.....

Regards

Irfanulla