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From: roger034@gold.tc.umn.edu (Brynn Rogers)
Subject: Re: STEPPER DRIVER INFO NEEDE
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References: <9408070631.A6509wk@circellar.com> <328nsb$h6c@handler.eng.sun.com>
Date: Wed, 10 Aug 1994 03:09:00 GMT
Lines: 35

In article <328nsb$h6c@handler.eng.sun.com>,
Chuck McManis <cmcmanis@Sun.COM> wrote:
>stephen.griswold@circellar.com wrote:
. . .
>:  Having seen this, when I got back from the meeting, I immediately dug into
>: my 'Junk Box' (Ok? Who also has one of these, or for that matter knows what
>: one of these is?) and found two identical stepper motors I had pulled from
>: a 'Fried' line printer, and a set of 4 Fairchild FT5753M Driver ICs.
>
>Are you kidding? My junk box fills half my lab :-) I'd suggest you bag the
>driver ICs unless by some random chance you get docs on them. You can build
>stepper driver functionality into your software if you've got spare cycles
>or build a simple digital circuit (or sophisticated uP based circuit). Also
>there are current generation drivers out, like the sprague UCN6003 (check

Sprague is not sprague anymore, it is Allegro.   They still make stepper
motor drivers and lots of other nice parts.   I am a firm believer in using 
their driver chips, and the UDN2916 is a very nice chopped current driver
for steppers, with the UDN2917 and UDN2918 handling more and more current.
The 2916 is 750ma (per phase, it handles 2) at up to 45 volts.  The 2917 is
1.5 A per phase (also hadles 2 phases).   
  My robot has two of the 2917 parts, work real sweet, you just set the max
current you want (you WANT to use a higher voltage than your motor is rated
for, it will limit it to the current you set),  and under software control
you can select 100%, 66%, 33% or 0% of the set current.

  Also my robot somewhat solves the 'drive in circles' problem because I can
step exactly the same amount on each wheel.  Of course if one wheel slips more
than the other, or if your wheels are not aligned very well, you still go
in circles, although big ones.  Four wheel drive helps here.

Brynn
--
Brynn Rogers     roger034@gold.tc.umn.edu

