connecting ULN2003 to Linux CNC

Those docs were never meant to give you advice on how to build a driver, but to show you how to connect various pieces to your breakout board.......you do have a breakout board, don't you ?

www.inet.home/linuxcnc/man/man9/stepgen.9.html

This explains the different types of motors stepgen can handle. I mentioned the stepgen manpage in my first post.

Those ULN2003 are very simple and rely on the connecting micro or circuitry to generate the timing and drive for each phase. You will need to look into have others have driven this board, using a Arduino or similar, to get an idea of how they are driven. That with careful reading of the stepgen manpage should put you on the right track.

A google search using the phrase "ULN2003 stepper driver linuxcnc" tunred up this thread forum.linuxcnc.org/16-stepconf-wizard/24...-darlington-array-ic

I really think that this way, other than for learning purposes, is not going to be of a great benefit, especially when you mentioned using servo motors.

Start with a standard config using a DIR-STEP driver.......you will get this setup going with the least amount of hassle.

The Gecko driver webpage has a wealth of info regarding the theory & operation of steppers.

Hi Todd,

I have read both pages... Yes I am absolutely sure this is the way it needs to be connected. It makes perfect sense.

Being noob and all, I know need to research how to create that halfile and then find out on which pins of the parallel port he is going to send out these pulses.

But this original question is hereby answered. Stepgen 4phases will drive the coils!

Thanks for providing the final answer!! Just want to mention. For people like me experimenting the first time with linuxcnc and having components from Arduino and rpi3. We all would probably have these kinds of motors laying around. Would be handy if somewhere there was a guide for linuxcnc. I might write one if I can get it running. Cause halfile is not so clear yet.

The uln2003 is merely a darlington transistor array. Not saying that you can't program numerous output pins to correctly sequence the transistors to drive a stepper motor, but you are going to use too many scarce parallel output card pins and cause yourself huge amounts grief doing it.

There are a wide variety of chips that have the necessary logic built into them for stepper control, including direction and enable and usually current control.

I suggest you decide what project you are working on, building a stepper motor controller, or building a linux cnc machine. Doing both at the same time is very difficult.

if the latter is your goal, at least start with a chip that is designed for stepper motor contol with features that are compatible with the currently programmed outputs of linux cnc, namely direction, step, and enable.

Hi,

Thanks for all your help.

So I bought a simple easydriver driver and nema17 for testing linuxcnc and getting to know it.

I posted my problems in:
forum.linuxcnc.org/27-driver-boards/3337...ow-to-get-it-to-work

I think that's a more appropriate place. Pls help me out, I can not get this to work and i have been researching for 5 hours now. I don't know what I'm doing wrong.

Great,


I managed to burn the easyDriver v4.5 , the smoke really stinks

So I would like to buy another driver to keep trying to get these basics to work.

But before I do. What would you guys suggest me, as a driver for 3 NEMA 17 motors. I would like to order these tonight on amazon.co.uk. I have seen gecko coming round here. And than preferably one that is kind of 'noob'proof.

I did get the uln2003 to work on a raspberry and I am reading through the hal file information.

You could try a driver such as I mentioned in, I believe, my opening post.

Hi ozzyrob,

I did order these ones as they are not expensive. I ordered 3 drivers and 3 motors.

And my first question about them is that I see that the ena+, dir+, pul+, all seem to need +5v . So where would that connection go? To an external 5v+, or can it come from the parallel port directly?

What is your basic knowledge of electronics\electricity ?

I think this needs to be stated so we, the forum, can direct you in the correct direction.

How much research have you done into setting up a CNC machine and what are your goals ? It just appears that some of your questions are a little bit more involved than getting Linuxcnc setup and using it.

The list of documents I posted a link for has a few examples of drivers being connected.

I would suggest before you connect anything else to your computer to research the kind of breakout boards others are using, many use a type that have buffers that add a small level of protection and extra drive capability to the Parallel port.

When looking for a breakout board I would advise you to choose a supplier that specializes in hobbyist CNC products and has a wealth of support documentation. Some of the generic products lack supporting documentation and if there is any there is a good chance it is poorly translated Chinese.

Cnczone is a great site with a wealth of information on everything from the basics of CNC to more advanced topics.

Hi ozzyrob,

What I am about to say now, will sound utterly ridiculous at this point

That being said... Up untill 4 days ago I never opened any document about linuxcnc nor schematics.

I was saving up till I had real time to get this under control... Point being in about 1 month from now I need to be able to reprogram 3 old robots with complete new drivers and connected to linuxcnc. That means I am studying 12 hours a day and I am busy 24 hours a day with this quest. Impossible? Well I know how I sound, ridiculous, but I mostly do exactly what I say I will do in the timeframe I give myself. I do a lot of things but never something I don't fully understand.

Knowledge of electronics. Let's say really limited but on the other hand, I am reading schematics, resistors, voltage regulators, diodes, capacitors,... Let's say I start to know their working quite well, it's self study, so many times problems come up that might be really simple if you know the exact questions to ask and that's many times the real problem.

I have a small jobshop, running a 4 axis CNC machine (mach3... And I hate it). So I know gcode, solidworks, solidcam, and studying mastercam as we speak. And on the bucket list this month is postprocessors development. I know c++, not saying I am a good programmer, but I easily and quickly read through code and know pretty well what it will do. I have basic knowledge of Linux, but rapidly expanding this basic knowledge.

My goals are as simple as all above , ... I need to be able to make anything I want spin and turn on linuxcnc. That's why my posts on the forum jump from left to right. The answers here come too slow to continue on 1 particular thing not wanting to say anything bad, this is a niche thing with limited amount of people, I am already superhappy I get feedback every time. Cause it helps out a lot.

I want to experiment with different drivers and difficult connection before I attempt to connect my working machine with el5-d1000 drivers to linuxcnc. Cause the jobshop can not be down for several days. If I than encounter problems I need to be able to handle them quickly without help.

So I ordered tb6600 6 drives in case I fry some. Ordered Mesa boards 6i25 and 2 7i85s for current machine. Ordered 2 different basic breakout boards with optocouplers. Bought 2 other second hand old computers in case I manage to fry the motherboard. Bought more electronics than fit in my drawer to be sure I have all I need when I need it .

Now learning the entire manual of linuxcnc by heart. Cause I am going to need that knowledge too.

The one important thing I haven't been able to find is what voltage should be on the parallel port when you tests axis in the stepconfig. Cause that is the only way to know if that parallel port is still working correctly. The wiki page on parallel port seems to be able to push my pins to 3.3 volt. So I guess it works but in a testrun in stepconfig the voltage goes to 0.07. which seems low to me.

So till now, wasn't able to get any motor working in linuxcnc. On the other hand i do understand the working of a steppercoil and the stepgen sequence needed to make them spin.

Well I guess I told enough ridiculous things now... But I am dead serious on how serious I am about linuxcnc.

Current and voltage requirements for lpt port:
www.edaboard.com/thread49356.html

More info on the LPT port:
retired.beyondlogic.org/spp/parallel.htm