Path: utzoo!attcan!uunet!zephyr.ens.tek.com!tektronix!gvgpsa!gold!grege From: grege@gold.GVG.TEK.COM (Gregory Ebert) Newsgroups: sci.electronics Subject: Re: Stepper Motor Help Message-ID: <821@gold.GVG.TEK.COM> Date: 2 Mar 90 19:54:14 GMT References: Organization: Grass Valley Group, Grass Valley, CA Lines: 26 In article 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!