emc2 setup with uln2803

[cjgaus]

Hey all i have built the following controller board

http://www.luberth.com/plotter/ditwasplotter.htm

I was hoping someone here could help me with step by step instructions on getting my emc2 configured.

Cheers

[irving2008]

Originally Posted by cjgaus Hey all i have built the following controller board http://www.luberth.com/plotter/ditwasplotter.htm I was hoping someone here could help me with step by step instructions on getting my emc2 configured. Cheers

i dont think you can. That controller (it isnt really, the ULN2803 is a buffer/driver) assumes the PC generates all the stepper motor signals for each coil, not step and direction signals which is what proper drivers use and EMC2 generates..

[cjgaus]

i found this following site on the web which shows u how to build a etch a sketch plotter using the uln2803 chips and emc2 but they had problems using just emc2 they also used axis. I have emailed asking for more information on axis with no luck of a reply. Anyways here is the link for you to check out.

http://axis.unpy.net/etchcnc

[cjgaus]

Anyone else got any other ideas for me?

[armstrong360]

I believe that there is a module that will drive a 4 phase stepped (rather than step/direction) I think its call motgen but am not sure

[samco]

emc2 stepgen hal module will do many step wave forms. (step/dir, Quadrature, 3 phase, 4 phase.. and so on)

http://linuxcnc.org/docs/2.3/html/ma...stepgen.9.html

You are looking at type 5 through 10. (lots of options.. fullstep, halfstep, and soe on)

sam

[cjgaus]

Thanks for that Sam i am reading that link at the moment but i dont quiet understand too well how to implement it into emc2. ( this is my first machine i am building) and its all new to me. I feel quiet dumb at the moment lol.

[marc_the_kiwi]

Originally Posted by samco emc2 stepgen hal module will do many step wave forms. (step/dir, Quadrature, 3 phase, 4 phase.. and so on) http://linuxcnc.org/docs/2.3/html/ma...stepgen.9.html You are looking at type 5 through 10. (lots of options.. fullstep, halfstep, and soe on) sam

Sam has the key here. EMC2 has many different ways of generating the appropriate output for different hardware.

Originally Posted by irving2008 i dont think you can. That controller (it isnt really, the ULN2803 is a buffer/driver) assumes the PC generates all the stepper motor signals for each coil, not step and direction signals which is what proper drivers use and EMC2 generates..

Yes, you can. EMC2 can generate many different signals (see the manpage as above). IMHO this is why open source projects are so good. Most coders/designers don't just implement one way of doing things, they expect people to want to take things a step further, or do it another way. Rather, as is the case here, the user can modify the stepgen hal module to output steps in many different modes.

Check out this link:-
http://www.linuxcnc.org/component/op.../lang,english/

Discussion on the very topic you are after with code showing how to change stepgen.hal. I'm sure you can figure it out from this, but if you can't either flick me a private message or post here.

I have just finished a test board setup with uln2803's. Initial testing leads me to believe my setup will work really well.. And my entire electronics/motors setup was under €80, and I expect my entire machine to come in well under €200. Just need to finish building my PCB milling machine so I can mill my pcb for my controller, get rid of this breadboard and mount everything properly!

[marc_the_kiwi]

Cjgaus, I've just realised the link I've posted points to the linuxcnc forums where you are the last person posting with problems with your setup!

Apologies. If you are still having difficulties, perhaps posting details of your setup (ie. either a board layout, or schematic, or if prototyped then which pins are assigned to each axes) would help.

Also, how confident are you that the hardware side of your setup is 100% accurate (it's not hard to overlook something small, even I do it now and again with 15 years worth of EE experience). Having tried the setup as suggested in linuxcnc.org forums, are you getting any movement at all (even micro movements or shuddering?) If the hardware is ok, then maybe it's something on the emc2 setup side of things.

The linuxcnc.org forum link in my last post is fairly self explanatory, though not everything may be clear to someone unfamiliar with linux/*nix environments, so if this is the case then I can take you through it step-by-step.

As I say, my test setup is working great and is practically a cut and paste of examples provided at the other forum.