Phil I have a few questions about your stepper driver boards.
Can you explain in brief the differences between the four driver boards on your site?
Allegro A3977, Allegro 5804, L297-298, and a discrete unipolar driver
What are the advatages of one over another, and how would someone choose which board suits one's needs?
Please excuse me if I'm missing something obvious, but I'm a newbie with electronics. :drowning:
I would suggest going to http://www.cs.uiowa.edu/~jones/step/types.html to read about the differences of stepper motors. Also http://www.cs.uiowa.edu/~jones/step/.
The 3977 and L297/8 board are bipolar drivers, the 5804 and discrete boards are unipolar drivers.
The 3977 and L297/8 boards are chopper drivers.
Both unipolar driver blank printed circuit boards can be built via toner transfer easily as they are single sided boards with a few jumpers.
The 3977 and L297/8 boards are double sided boards. While they probably can be built with toner transfer, it would be the person who is pretty competent at that method. On the 3977 board the 3977 part is a surface mount part. It takes a good soldering iron and some skill to put on. Definitely not for the first time solderer.
Current driver capabilities are also different.
5804 1.25 A
3977 2.5 A 35V
L297/8 2 to 3A depending on DC or chopped
Discrete – probably up to 6 A at 30VDC
Hope this helps.
Phil
slp,
How you doing? Was wondering your latest progress.
Phil
tachus42:
I made some minor changes (went to lm317 to give a little more headroom for the FETS, slight change in probe logic) and uploaded your 3 channel board:
http://webpages.charter.net/pminmo/cncelectronics.htm
Got it down to 9 jumpers, changed the logic probe for three states open, low and high. Started a information document. Please review.
Phil
pminmo,
I almost gave up on the other board that wasn't working,
I had the 4030 replaced, but nothing works. I set it aside
and work on the 5804 version, but I couldn't make it work too,
again I set it aside and built another discrete comp. board
(darn those sensitized board are expensive).
It went fairly well and I got it working :).
then I decided to work on the defective board again replace the IC8 & IC2 again( I gotta have to learn a lot more of circuit analysis), this time I got me a sockets, cleaned up the solder a bit then did the
probing test and it pass, I had it hook with the small motor and it works.
I now have 3 working discrete comp board(haven't test yet with my larger motor) and not yet working 5804 version,
I also got me an AT psu, it has 9.5A on 12V and 25A on 5V, but I have to perform the hobby.cnc.co.m psu hacks, I have tried the psu and
it's actually giving out 11V, I wonder if it is enough to drive 3 motors
5.2V 1.4A/phase.
here's the boards on temp housing, no BOB yet,
Way to go slp! Don't forget current limiting resistors with your motors if you use the 12V side. There has to be a load on the PSU output for a correct regulated voltage. You might try running your 5.2V motors on the 5V side of the supply. Depending on the motors and the actual load you maybe fine. You wouldn't need current limiting resistors then.
Phil
slp btw when your ready I can talk your through troubleshooting the 5804 board.
Phil
Uploaded a new document pdf file for the single channel unipolar board.
Phil
pminmo,
I use a 12V psu fan as a load on the 5V side,
I don't have the resistors yet, I wanted to try
the resistors I got from the laserjet psu where
I got the motors it's 6.8ohms I'm not sure if it's
a 10W tho, I'm going to try the motors with the 5V,
and see what happens.
thanks, I also want that thing working as a backup & a learning experience.Quote:
slp btw when your ready I can talk your through troubleshooting the 5804 board.
Phil
slp,
you might want a bigger enclosure so that a BOB fits also.
Phil
Re 3 channel board.
Phil excellent but..
I had kept the power and signal grounds separate - it will most likely be ok merged but i think for the cost of a few jumpers it's best to avoid any strange problems before they occur. If the logic probe led is on the emitter of the transistor there will be a sharper transition between off and on at about 2.3 volts.
Perhaps we should specify a logic level mosfet as first choice for output device with a alternative option to use a standerd one with a different volt setting resistor.
I have come up with a circuit (4 transistors and a mosfet) which could be used, one per motor instead of ballast resistors to make this driver into a chopper. I haven't built it but have simulated it extensively in spice and it works well. If anybody is interested I'll lay it out and post it.
tach,
Amazing, as I was going over the board, I was thinking (concerned) about the heavy current switching effect, but it didn't realize you had the two gnd's seperated. I think I can still keep em seperate and eliminate two jumpers. (Another note, didn't realize you could have two seperate polygons with the same name. Never tried, never even considered trying.)
317 vs 7805, I figure it left a couple of options for the cost of 2 resistors. Since the 74hc can work 4 to 6 volts I thought it might also give some options on threshold with the pport. Raising the hc voltage may have a negative affect there. The 7805 can be in spec at 4.8, which coupled with a batch of 44Z's that might be on the high end of gate characteristics "might" become an issue. The other thing that crossed my mind was two seperate regulators or run the 317 higher and a diode drop to run the hc14 lower. i.e. the hc14 at 5V and the 4000 at 5.7. Your correct on the probe, I wasn't working with the latest file. I did want to have 3 recognizable states, low, open, hi but it works better with that arrangement anyway. I'd like to see the chopper circuit, think it would be a better option. The thing about the 44Z is they are pretty cheap and available, unless one particular manufacturer has a lower threshold than the fairchild spec, I don't know that I'm catching the STP30NE06 having a lower threshold than the 44Z? What am I missing?
Last thought is the direct drive from the cmos to the gate. Putting a series resistor in could use the gate capacitance and slow the on/off transistions and help bring noise down in high current applications.
Phil