connecting ULN2003 to Linux CNC

Hello,

So i gave up on my raspberry pi idea, as it is apparantly not possible with my limited knowledge and so it seems on the forum, noone has tried that road

Luckily i found an old computer here that still has a printerport on it, so i installed linuxcnc using the liveCD which seems to have worked perfectly.

I am a complete newbie here to this, so my first thought is, try to connect one stepper motor to this in the stepconfig, connect the correct pins and test the motor. Well i have been with my hands in my hair again.

I have here 6 pieces of ULN2003 driver board and step motor 28BYJ-48, but how do i connect these, there are 4 pins going out and as far as i see i only have Xstep and Xdir in linuxcnc on the parallelport. So i am at a complete loss. I can not find online which of these pins need the step and which need the dir.
( www.technobotsonline.com/images/detailed...059.jpg?t=1449659180 )

Later i should connect El5 D1000 Drivers from leadshine, they have a 44pin connector that needs to go to the motion controller. I know i will have to buy a mesa card for these connections but how will i ever find out which pins goes where???????

I also have here micro servo motors, but these have only 3 pins. Ground , +V and signal , so than again i am one short.

I have tried to open in the config picker a simulation machine with 4axis and leadshine drivers, but when i save this, i can not open these ini files with the stepconf wizard or pncconf wizard to have a look at those settings?? I thought it was possible to start from a machine in the config picker and slowly adapt that one to my particular machine, in the manual i found this as explanation, but not a clue on how to do this.

Anyway the el5 d1000 drivers is not for today anyhow, i would be happy if i can just get this test stepper here to work cause step/dir but 4 pins to connect and only 2 in linuxcnc, i don't know how to proceed.

I have set my mind on linuxcnc, you have no idea, but i am going to need some help here guys... So please any advice is welcome.
I love technical things and i don't mind studying every day of the week, but this entire thing is so all over the place, i am at a loss.

Regards

Stephane

Hi,

For experimenting I would put the UN2003 setup on hold and obtain a 4 NEMA 17 Stepper (they are cheap) and a EvilBay Stepper Driver suach as El' Cheapo Driver . This should minimise the gnashing of teeth and pulling of hair........with a bit of luck.

I don't claim to be an expert, but this is the way I would proceed.

The stpegen man page does mention other ways of driving a stepper motor, but someone with more experience would be needed to guide you.

The ini files can be opened with a text editor to have a look at, along with some time, study and the Manual you should get an idea of what is going on.

Hopefully someone more experienced will chime in and let you know where I have made some glaring mistakes, add some more suggestions or encouragement.

Initially Linucnc can have a steeper learning curve compared to Mach3 or GRBL......but after a bit of time you come to realise that the things you can do with are fantastic. Even adding a simple HAL component to do a "custom" action is rather simple. What I guess I'm trying to say is that is quite more extensible even with a basic understanding.

Good Luck

Thank you for giving me the first answer on this forum.

I will follow your advice and ordered an easydriver and nema17 motor on Amazon. That one has only step dir and ground. Hopefully that will be connectable.

I still need to find out how to connect real drivers. (El5 d1000) but I am convinced you are correct that linuxcnc is a beauty.

It is just frustrating sometimes that information is so scattered at times. I have been reading the manual and a lot of information but I still feel like I have no grasp on it.

Hopefully there are a lot of active users here that help out, cause without help I don't think I can muddle through . I have one spair servo and el5 d1000 leadshine driver I could use. But that thing seems way to complicated for now.

I will also need advice on which Mesa cards to buy, cause I still need to order them.

Thanks again for your help already!

there are three signals for each joint. a joint is a motor to pc connection. an axis is a direction of movement, x, y, z and a for rotation.

you may have more joints than axis' if you build a machine with more than one motor to move say a gantry from both ends with to motors.

try to stick with one motor per direction for your first machine.

Grab an image from an internet supplier for a Standard Pin Configuration. I used a probotix non isolated breakout board. this gives you up to four stepper motor connections and the left over pins to connect limit switches and spindle, or torch control.

you can protect your parallel port by buffering the pins with optocouplers or buffer ic's.

Use stepconfig for now and stay out of the ini and hal files. basic setup, limits, spindle control is pretty easily acheived using that config tool with an interface that is user friendly.

the servos with three pins are a different animal. they use a pwm signal to command the servo to an absolute position. put those back in your parts bin for now.

the steppers are dumb, ccw, cw, and how many steps. thats where the homing switches come in. Your machine has to learn where zero is each time you turn it on. I will search for a schematic of a breakout board and post it for you.

you dont have to buy the breakout board if you are handy, have an old printer cable and some prototyping board.

probotix break out board connection diagram

This is my second parallel port homebuilt breakout board. i configured the data lines as inputs. each input has a pushbutton, and a jumper pin set to disable an input. each output has a led for status. there is an inductor and capacitor on each input to buffer noise. i have learned from experience that parallel ports are sensitive and will pick up noise in external wiring and cause nuisance signals. i now buffer input signals with 4n26 optocouplers and have had goid results. some folks write software debouncers, but im better at hardware than software

Hi, thanks for your replies.

I have here a lot , lot of electronics laying around. I bought a lot , I mean a lot of sets on AliExpress, in case I would need it.

So your idea of that board is nice as it is the perfect way of learning things. Would you have a diagram for one axis how you connect and more importantly why. Cause just copying will not make me learn the logic behind the build.

I need to know the why and how the capacitors are used and a diagram including leds and pushbuttons for one connection. Than I can figure out the rest.

I don't want to blow the only motherboard with parallel port I have laying around.

Hopefully you could help me build this.

Stephane

Hi,

If you go to www.homanndesigns.com/index.php?main_page=page_2 and have a browse thru some of the docs you'll get an idea of how things go together. I'm not pushing this particular manufacturer, but there is a good range of docs showing various setups.

Hi,

I have been going through these documents but I am sorry, I don't see how I could build a driver out of it.

Nor can I find how I would have to wire this uln2003 to be able to connect to a parallel port for commands with Linuxcnc.

I dit find how these 4 coils work in the motor a /a b /b

Still have not a clue how to get these uln2003 boards connected to linuxcnc

This site has a good explanation.
electronics-diy.com/stepper_motors.php

In Linuxcnc I think you need to configure the stepgen to use one of the 4phase types 5, 6, or 9 (I think I'd choose 9 half step mode)
linuxcnc.org/docs/html/hal/rtcomps.html