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EASY STEP'n

Square 1 Electronics' new book, "Easy Step'n", An Introduction to Stepper Motors for the Experimenter,"   explains to the reader how to determine surplus motor electrical and mechanical specs by using easy-to-build electrical and mechanical test equipment. The experimenter will learn to design and build microcontroller based control systems and to design and build driver circuits to switch power applied to stepper motor windings. The book is hands-on and full of experiments. The format of the books uses flow charts and many code examples in a step-by-step approach. The complete table of contents follows:

Please note: This book is available only from us, Square 1, or from the usual catalog electronics suppliers. It is not available in bookstores.

Table of Contents

INTRODUCTION

Terminology

Coil vs. winding vs. phase

Stepper Motor Types

Stepper Motor Specifications

Stepper Motor Selection Criteria

Stepper Motor Sizes

  • NEMA "Teen" Cubes
     
  • NEMA Size 23 Cylinders
     
  • Stacked Cans With Diamond-Shaped Mounting Flange

    • Rough Motor Specs - Based On My Experiments

    Gear Puller

    GETTING STARTED
     

    4-Phase Stepper Motors
     

    Exercise motor with four SPST toggle switches and a power supply

    Testing 5-wire and 6-wire motors

    - Full steps - one winding energized (wave drive)

    - Full steps - two adjacent windings energized in each

    detent position (normal mode)

    - Half steps - alternately one winding energized, two

    adjacent windings energized

    Testing an 8-wire motor

     

    2-Phase Stepper Motors

    Determine wiring with ohmmeter
    Exercise motor with two DPDT on-off-on toggle switches and a
    power supply

    - Full steps - one winding energized (wave drive)

    - Full steps - two windings energized (normal mode)

    - Half step sequence - alternately one winding energized,
    two windings energized

    MICROCONTROLLER-BASED STEPPER MOTOR CONTROL - INTRODUCTION

    PICMicro® instruction set
    Hexadecimal notation Compare using PICMicro® Interrupt service and saving context

    TEST CIRCUITS OVERVIEW

    Overview

    Test Board for Exercising Stepper Motors

    Pulser
    Switches And Pull-ups
    Construction Techniques And Board Design
    Pulser software
    Testing the pulser

    Translators

    PIC16F84A translator (unipolar bit pattern)

    - Software design

    - Hardware design

    - Code

    - Testing the PIC16F84A unipolar translator

    PIC16F84A translator (bipolar bit pattern)

    - Design

    - Code

    - Testing the PIC16F84A bipolar translator

    Simple Drivers

    Unipolar

    Simple ULN2803A driver
    Exercising a unipolar stepper motor using a pulser, PIC16F84A
    translator and a ULN2803A unipolar driver
    Simple TIP120 driver
    Exercising a unipolar stepper motor using a pulser, PIC16F84A
    translator and a TIP120 unipolar driver
    UCN5804B translator/driver
    Exercising a unipolar stepper motor using a pulser and a UCN5804B translator/driver

    Bipolar

    H-Bridge
    L293D driver (dual H-bridge)
    Exercising a bipolar stepper motor using a pulser, PIC16F84A
    translator and an L293D bipolar driver
    L298N driver (dual H-bridge)
    Exercising a bipolar stepper motor using a pulser, PIC16F84A,
    translator and an L298N biopolar driver

    TORQUE MEASUREMENT

    Motor (what's available) via lever arm and weights

    - Holding, add weight until slips

    - Moving, add weight until won't turn

    Application (what's required) via lever arm and weights
    Lever arms and fishing sinkers

    MAXIMUM STEP RATE MEASUREMENT

    MICROCONTROLLER-BASED STEPPER MOTOR CONTROL

    Unipolar

    Simple unipolar stepper control - straight line code

    Full steps - one winding energized

    How to reverse direction

    Change delay time to change speed

    Table lookup and counter to get bit pattern for each step

    Full steps - two windings energized

    Half step sequence

    Exercising a unipolar stepper motor using a microcontroller,
    PIC16F84A translator and a ULN2803A or TIP 120 unipolar driver
    Exercising a unipolar stepper motor using a microcontroller and a UCN5804B translator/driver

    Bipolar

    Exercising a bipolar stepper motor using a microcontroller and
    an L293D or L298N bipolar driver

    HIGH PERFORMANCE DRIVE CIRCUITS - Current Control

    Limitations of voltage control and need for high performance current control

    Unipolar

    SLA7024M unipolar driver - Allegro Exercising a unipolar stepper motor using a pulser, PIC16F84A translator and a SLA7024M driver

    - Maximum stepping rate at higher than rated voltage

    - Torque operating at higher than rated voltage

    Bipolar

    L297/L298N bipolar translator/driver Exercising a bipolar stepper motor using a pulser and a L297/L298N translator/driver

    - Maximum stepping rate at higher than rated voltage

    - Torque operating at higher than rated voltage

    Exercising a bipolar stepper motor using a microcontroller and a L297/L298N translator/driver

    Controlling A STEPPER MOTOR WITH A PC

    Serial port, parallel port
    Programming languages
    Port board, not mother board

    MECHANICAL CONSIDERATIONS

    Mounting The Stepper Motor And Heat Dissipation

    Grabbing On To The Shaft = Mechanical Connection

    Avoid damaging the shaft (clamp, flat, split hub)
    Shaft couplings - alignment, flex
    Avoid applying a thrust load to the shaft

    Converting Rotary Motion To Linear Motion

    Mechanics

    Torque
    Inertia

    Position - Home Or Starting Position Sensor

    Test for accuracy

    Backlash

    NEMA 23 Tester

    PRINTER EXPERIMENT

    Software design Code snippet Implement your design

    QUICK STEP'n

    Test Hardware
    Software design details
    Home Position
    Ramping up/down and rapid traverse

    - Ramping up - acceleration

    - Ramping down - deceleration

    Speed - rapid traverse
    Destination
    More software details
    Code

    APPENDIX A - Fast Diodes

    APPENDIX B - Parts Lists

    APPENDIX C - Sources

    APPENDIX D - Program Listings vs. Page Number

    Buy Easy Step'n HERE

    Download the PIC source code for Easy Step'n HERE


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