Driver recomendations

[sp00k1e]

My Hans Wedemeyer L297/8 board just blew up. The magic electronic smoke escaped from the 298 when I turned on the power. So it is maybe time for a change. I have had no problems with this chipset even though I built it on veroboard and was planning on upgrading it to a prober milled pcb. I use a bungard CCD pcb Mill at work.
My question is what are the advantages over the 297/8 chipset, if any, of the other chipsets designs around. I fancy Alans LMd18245 PICSTEP board, but in the UK the chips are about £11 each (unless anyone knows a cheaper source) and will my machine run faster with more power or be about the same. I have looked at pminmos circuits maybe you could answer seeing as you have seemingly built every combination available? I was going to build your 3977 board but the cost of importing the chips from the US was prohibitative, as i cant find them over here.
I have 6 lead 2A steppers to control

Thanks Paul

[MrBean]

You can get the 3977 in the UK from Farnell.

http://uk.farnell.com/jsp/endecaSear...KU=4126075&N=0

£3.72 ea. Not sure if tat includes VAT though.



Regards Terry.....

[pminmo]

Paul,
What is your power supply voltage? What is your coil voltage or resistance?

Phil

[andyew]

spookie Paul,

as mrbean Terry said, Farnell (Newark actually) has em in stock..... A3977SED is listed there quite cheap... from my part of world, it takes 2 weeks from order to postman reaching my house since it's from Newark US.

Good luck and phil is really helpful, he will guide u the right direction, just bear with him sometimes, look at his signature u will know...... :P
Andy

[sp00k1e]

Yes Farnell has the 3977 in stock, but since they are from Newark the postage is another £13, not too bad i suppose if they are what I want. My power is a rectified smoothed 25v toroid so about 35v, but that could easily change, and the X and Y motors are Sanyo Denki 103H7126-0440, I cant find the specs at the moment but I seem to remember about 3.5V, rated 2A on the case. The Z at the moment is a 6V printer motor.

[pminmo]

Under 2.5 amps and 35V the 3977 is a great chip. But you have to be able to solder well and very fine. The L297-8 is my second choice. One the pricey side is the picstep board, but the driver is a gem.

Phil

[MrBean]

Originally Posted by sp00k1e Yes Farnell has the 3977 in stock, but since they are from Newark the postage is another £13

That's not good. All the orders I've placed with them have not had postage charged. Maybe I've just been lucky.

Regards Terry.....

[sp00k1e]

I think then I will try and sneak a few 3977 on my next order and try and hide the postage cost

[sp00k1e]

Well I have managed to get my 3977, almost double the cost due to the postage from the states, but delivered in less than 48 hrs.
I have milled one board to try, a slightly modified version of phils circuit so that I could transfer it onto the PCB mill at work. only a few more components needed and then we will see what it can do. You can see I lost a couple of pads from the top of the chip when I was trying to clean up the remaining copper, a couple of wire links will sort that out. Next one I will do a full mill to remove the excessfrom around the chip.

Paul

[pminmo]

spook1e,
Looks good, keep us posted.
Phil

[H500]

The board looks good. 35v might be bordering on the high side. When the motors are decellerating they put out back emf that could potentially cause the supply voltage to go too high and zap the 3977.

[sp00k1e]

Well ive built the 4 axis breakoutboard and one drive, and now have it almost working, when I enable the drive the motor locks as expected, but it just very quietly whispers and wont move, it is probably a fault on my remanufactured boards but just to check, and before i can get my scope from work, the double sided version circuit has a 10k pullup on the dir signal but the single sided doesnt. I understand that in general the printer port is TTL but it may be open collector, but i guess the 7414 should sort that out shouldnt it?
Paul