From: Paul Burke
Subject: Re: CNC with steppers
Date: Wed, 04 Dec 2002 08:48:19 +0000
Organization: Scazon Systems
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> I am totally confused.
> I spent two days to browse many homebuilt CNC sites but I have not
> understood the principal answer.
> Here is my problem : I own an old plotter with two powerfull bipolar
> steppers and I would like to transform it to an engraver, and if
> possible to a drill machine.
> First of all, I have to build a new control unit to drive the steppers
> because mine is dead. I have seen may schematics for unipolar but only
> a few for bipolar motors.
> My question is : are all these interfaces (UCN5840, ULN2803, PBL3717,
> L297 etc etc etc) compatibles ?
> If I build an interface based on 3717, will it work with softwares
> written for unipolar interfaces ?
> Thanks for the help I need...
You seem to be just beginning this electronics game. If you want t get
something that actually works, at this stage, just find a design
(hardware and software) and follow it straight.
I've not looked at all the devices yo quote, but there are various sorts
of drives and controllers:
H- bridge drives
4 phase single- ended drives
Current controlled (often microstepping)
In addition, some of these want the controlling software to provide them
with correctly phased outputs, others wnat a direction and step input,
and others still just take a "goto X" command and do the whole
acceleration, move, deceleration sequence for you.
And that's before you've sorted out the correct voltage/ current to
drive your motors at....
As I said, just get hold of a design, and foillow it carefully while
learning why particular things have been done that way.