[sci.electronics] Stepper Motor Help

tf0z+@andrew.cmu.edu (Todd Andrew Ferrante) (03/02/90)

I have a number of small stepper motors I want to use for a robotics
project.  These were purchased from American Design Components a couple
years ago.  They are N. A. Phillips  part no A82310-M2.  Step angle 1
degree; 5 volts DC; Stall Torque 17 oz-in.  These have four wires, two
going to each of the two coils.  Can anyone suggest to me a circuit to
use that will let me get a range of motor speeds as well as reasonable
power output from these things?  Almost every circuit I have seen has
commen power leads for the two coils, these don't exist on this motor. 
I want the motors to be controlled by an IBM PC using the parallel or
serial port for I/O.  Also, how should I interface the digital circuitry
to the motors themselves?  I have seen circuits using transistors as
switches for current through the coils, but I'm not real good with
analog circuits.  Any help would be appreciated even if it is just a
referance to a book or magazine article.        Thanks,   Todd

jans@tekgvs.LABS.TEK.COM (Jan Steinman) (03/02/90)

<I have a number of small stepper motors I want... be controlled by an IBM PC 
using the parallel or serial port for I/O.>

*Computer Interfacing with Pascal & C, Hardware + Software Projects on your 
PC*, Bruce Eckel, 1988.  Purchase through eiysy, 1009 N 36th St, Seattle, WA, 
98103, 29.95 includes disk with software.

Chapter 1: Connecting A Stepper Motor to Your Computer.

							   Jan Steinman - N7JDB
					Tektronix Electronic Systems Laboratory
					Box 500, MS 50-370, Beaverton, OR 97077
						(w)503/627-5881 (h)503/657-7703

hbg6@citek.UUCP (John Schuch) (03/03/90)

In article <AZvKRje00WBLQ1zFUy@andrew.cmu.edu> tf0z+@andrew.cmu.edu (Todd Andrew Ferrante) writes:
>I have a number of small stepper motors I want to use for a robotics


Look up the Motorola part SAA1042 ( or SAA1042A ). It is a stepper motor
driver ic. It drives two coils with no common lead and provides inputs
for CW/CCW rotation direction, full/half step, and a clock input which
determines speed of rotation. There is also some bias nonsense but the
data sheet will explain that. It directly drives steppers from 5 to 12 Vdc.
The 1042A can drive 24Vdc motors.

I've set one up to run off of an XT serial port using a simple serial
to parallel converter published in one of the trade mags. The parallel
output lines go to the CW/CCW, full/half, and clock inputs. This lets
me control two steppers via one serial port. I move the motor one step
by fliping the clock bit. At 9600 baud the motor moves fast enough for
my needs.

If you can't find the data sheet, Email me and I'll see what I can do.

John

grege@gold.GVG.TEK.COM (Gregory Ebert) (03/03/90)

In article <AZvKRje00WBLQ1zFUy@andrew.cmu.edu> tf0z+@andrew.cmu.edu (Todd Andrew Ferrante) writes:
>I have a number of small stepper motors I want to use for a robotics
>project.

SGS-Thompson's "Industrial and Computer Peripheral IC's" databook describes
such a beast. Their rep in NY is at (516) 935-3200.

Four-wire stepper motors are not hard to use ! First, take a beeper to find
which 2 windings are 'paired' ( There are 2 separate windings). I'll describe
how to make it turn. Call one set of windings A-B; the other C-D. For brevity,
the term 'AB' means that wire 'A' is at (say) + 5 volts, and 'B' is 0. 'BA'
means 'B' is at +5 and 'A' is 0. Here we go !!!!

	The pattern is AB,CD,BA,DC,AB,CD,BA,DC.... If, perchance the motor
just vibrates, one winding is open. To reverse rotation, apply :

	AB,DC,BA,CD,AB,DC,BA,CD  (ie, reverse the pattern)

	This gives coarse stepping. You can get smoother stepping by using
more sophisticated patterns which energize both windings simulataneously
and use 1/2 current, etc.

NOTE, NOTE, NOTE : If you concoct discrete drivers, USE REVERSE-BIASED DIODES
to conduct-away the inductive energy. It WILL destroy your transistors. Enjoy!