Progect II 070933
Transcript of Progect II 070933
By: Fadel H. Ramadan Project II, EEE 450
ID: 07075933 Supervised By: Dr.Osama Al Rawi
BSC in Electrical Engineering
Gulf University
College of Engineering
Electrical and Electronic Engineering Department
Control Stepper Motor Manually A project
Submitted to the Electrical and Electronic Engineering Department/
Gulf University in partial fulfillment of the requirements for the degree of Bachelor of Science in Electrical Engineering
By:
Fadel H. Ramadan
Supervised by:
Dr. Osama Al-Rawi
Submission Date :9/5/2012
Acknowledgment
By: Fadel H. Ramadan Project II, EEE 450
ID: 07075933 Supervised By: Dr.Osama Al Rawi
BSC in Electrical Engineering
At the beginning most people told that it will be hard and the effort will be in vain
but our belief in ourselves and our faith that we can make the future of our
University better was and still our motivation. To set an example of the "Source Of
Quality Education'' But we would achieve nothing without the help of those who
has given us the encouragement, time and effort. So we dedicate the project for all
who had helped us and enlighten our way with their vision. So thank you
Dr. Nouaman Nouaman
Dr. Osama Al-Rawi
Dr. Mohammad Majid
Thanks to everyone helped and believed in us
Thank you all
By: Fadel H. Ramadan Project II, EEE 450
ID: 07075933 Supervised By: Dr.Osama Al Rawi
BSC in Electrical Engineering
AbstractStepper motors are extremely important to the industry as it is used in many
applications depends on position control like filling and packaging. But this kind of
motors requires special driving technique. Our project aims to build Hybrid
Unipolar Stepper Motor Driver can withstand up to 50 Volt and 1 Ampere with
high accuracy ,simple interface and easy maintenance.
The controlling method is manually using set of 555 IC timer and a 4 bit Universal
shift register DM74LS194A to produce the sequence pattern.
The project targets the students of electrical engineering to get a general picture of
this machine and it's characteristics.
By: Fadel H. Ramadan Project II, EEE 450
ID: 07075933 Supervised By: Dr.Osama Al Rawi
BSC in Electrical Engineering
List of Abbreviations:
IC: Integrated Circuit
DC: Direct Current
PM: Permanent Magnet
VR: Variable reluctance
RPM: revolutions per minute
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
Table of Contents
1. Acknowledgment
2.Abstract
2. List of Abbreviations
- CHAPTER ONE: INTRODUCTION
1.1 Introduction
1.2 Motivation
1.3 Aim of the project
- CHAPTER TWO: Theoretical Background and Applications
2.1 Introduction: '' What is Stepper Motor and What are its basic
characteristics? ''
2.2 Early history of stepper motors
2.3 Types Of Stepper Motors
2.3.1 Permanent-magnet (PM) Stepper Motors
2.3.2 Variable-reluctance (VR) Stepper Motors
2.3.3 Hybrid Stepper Motors
2.3.4 Two-phase stepper motors
a. Unipolar motors
b. Bipolar motor
2.4 Applications
- CHAPTER THREE: Practical Experiment
1
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
3.1 Introduction
3.2 The Circuit Driver
3.3 Basic Stepper Motor Driver Operation
3.4 Inputs Vs. Outputs Waveforms
3.5 Integrated Circuit Chips Used
3.6 74194 Stepper Motor Driver Notes
3.7 74194 Stepper Driver Initialization Notes
3.8 Stepper Circuit Board Parts List
- CHAPTER FOUR: Conclusion
3. References
4. Appendices: Data Sheet
2
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
CHAPTER ONEINTRODUCTION
1.1 IntroductionThis report is about one type of many of electrical machines, in particular the one
which converts electrical energy to mechanical energy. DC Motors and Stepper
Motor in particular which I will clarify and the main topic of this report.
Here I give only short review and important at the same time for an electrical
engineer knowledge and to be familiar to deal with such motors that can be found
around us and depend on it daily at home , office, factory, and even a hospital .
The way that I'm going to explain is first to mention the requires information and
background and at last an experiment of sampling a circuit to drive a stepper motor
to put a picture in mind and let the information fit which each other.
1.4 MotivationThis report has done to implement my knowledge and study of Electrical
Engineering major it is presented to My Instructor DR. Osama Al-Rawi
and it is basic since it is requirement as graduation project.
1.5 Aim of the projecta. Explain what is stepper motors and their theory.
b. Show the History of this machine.
c. Some Application.
d. Using simple and available discrete components to drive the motors.
3
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
CHAPTER TWOTheoretical Background
andApplications
2.1 Introduction:
'' What is Stepper Motor and What are its basic characteristics? '' [1]
Figure 1.1[2] Illustrates the cross-sectional structure of a typical stepper motor; this
is so called single stack variable reluctance motor. We shall first study how this
machine works, using this figure. The stator core has six silent poles or teeth, while
the rotor has four poles, both stator and rotor core being of soft steel. Three sets of
windings are arranged as shown in the figure. Each set has tow coils connected in
series . A set of windings called 'phase'. And consequently this machine is a three-
phase motor. Current is supplied from a DC power source to the windings via
switches I, II and III.
In state :
(1)The winding of phase I is supplied with current through switch I or 'phase' I
is excited in technical terms .The magnetic flux which occurs in the air-gap
due to the excitation is indicated by arrows. In state (1), the two stator salient
poles of phase I being excited are in alignment with two of the four rotor
teeth. This is an equilibrium state in terms of dynamics. When switch II is
4
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
closed to excite phase II in addition to phase I, magnetic flux is built up at
the stator poles of phase II in the manner shown in state (2), and a counter-
clockwise torque is create owing to 'tension' in the inclined magnetic field
lines. The rotor will then, eventually, reach state (3).
Thus the rotor rotates through a fixed angle, which is termed the 'step angle',
15ᵒ in this case, as one switching operation is carried out. If switch I is now
opened to de-energize phase I, the rotor will travel another 15ᵒ to reach state
(4). The angular position of the rotor can thus be controlled in units of the
step angle by a switching process. If the switching is carried out in sequence,
the rotor will rotate with a stepped motion; the average speed can also be
controlled by the switching process.
Nowadays, transistors ate used as electronic switches for driving a stepping
motor, and switching signals are generated by digital ICs or a
microprocessor (see Fig. 1.2).[3] As explained above, the stepping motor is
an electrical motor which converts a digital electric input into a mechanical
motion. Compared with other devices that can perform the same or similar
functions, a control system using a stepping motor has several significant
advantages as follows:
(1) No feedback is normally required for either position control or
speed control.
(2) Positional error is non-cumulative.
(3) Stepping motors are compatible with modern digital equipment.
5
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
For these reasons, various types and classes of stepping motor have been used in
computer peripherals and similar systems.
6
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
2.2 Early history of stepper motors.[4]
(1) An issue of JIEE published in 1927 carried an article '' The Application
of Electricity in Warships'', and a part of this article described a three-phase
variable-reluctance stepping motor of the above type which was used to remote-
control the direction indicator of torpedo tubes and guns in British warship.
(2) According to an article in IEEE Transaction on Automatic Control,
stepping motors were later employed in the US Navy for a similar purpose.
Though practical applications of modern stepping motors occurred in the 1920s,
the prototypes of variable-reluctance motors actually existed in earlier days. We
shall here refer to two noteworthy inventions made in 1919 and 1920 in Britain.
a. Tooth structure to minimize step angle. A UK patent was obtained
in 1919 by C.L Walker, a civil engineer in Aberdeen, Scotland, for the invention of
a stepping motor structure which can more in small step angles (see Fig. 1.3.)[5]
7
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
b. Production of a large torque from a sandwich structure. C.B
Chicken and J.H Thain in Newcastle upon Tyne in 1920 obtained a US
patent for the invention of a stepping motor which could produce a large
torque per unit volume of rotor. The longitudinal construction of this
machine is shown in Fig. 1.4[6]
8
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
2.1 Types Of Stepper Motors:[7]
2.1.1 Permanent-magnet (PM) Stepper Motors: The permanent-magnet
stepper motor operates on the reaction between a permanent-magnet
rotor and an electromagnetic field. Figure 1.5 shows a basic two-pole
PM stepper motor. The rotor shown in Figure 1.5 (a) has a permanent
magnet mounted at each end. The stator is illustrated in Figure 1.5
(b). Both the stator and rotor are shown as having teeth. The teeth on
the rotor surface and the stator pole faces are offset so that there will
be only a limited number of rotor teeth aligning themselves with an
energized stator pole. The number of teeth on the rotor and stator
determine the step angle that will occur each time the polarity of the
winding is reversed. The greater the number of teeth, the smaller the
step angle.
Figure 1.5
When a PM stepper motor has a steady DC signal applied to one
stator winding, the rotor will overcome the residual torque and line up
9
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
with that stator field. The holding torque is defined as the amount of
torque required to move the rotor one full step with the stator
energized. An important characteristic of the PM stepper motor is that
it can maintain the holding torque indefinitely when the rotor is
stopped. When no power is applied to the windings, a small magnetic
force is developed between the permanent magnet and the stator. This
magnetic force is called a residual, or detent torque. The detent
torque can be noticed by turning a stepper motor by hand and is
generally about one-tenth of the holding torque.
2.1.2 Variable-reluctance (VR) Stepper Motors: The variable-reluctance
(VR) stepper motor differs from the PM stepper in that it has no
permanent-magnet rotor and no residual torque to hold the rotor at
one position when turned off. When the stator coils are energized, the
rotor teeth will align with the energized stator poles. This type of
motor operates on the principle of minimizing the reluctance along
the path of the applied magnetic field. By alternating the windings
that are energized in the stator, the stator field changes, and the rotor
is moved to a new position. The stator of a variable-reluctance
stepper motor has a magnetic core constructed with a stack of steel
laminations. The rotor is made of unmagnetized soft steel with teeth
and slots. The relationship among step angle, rotor teeth, and stator
10
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
teeth is expressed using the following equation:
Figure 1.6 shows a basic variable-reluctance stepper motor. In this
circuit, the rotor is shown with fewer teeth than the stator. This
ensures that only one set of stator and rotor teeth will align at any
given instant. The stator coils are energized in groups referred to as
phases. In Figure 1.6, the stator has six teeth and the rotor has four
teeth. According to the above mentioned Eq. , the rotor will turn 30°
each time a pulse is applied. Figure 1.6 (a) shows the position of the
rotor when phase A is energized. As long as phase A is energized, the
rotor will be held stationary. When phase A is switched off and phase
B is energized, the rotor will turn 30° until two poles of the rotor are
aligned under the north and south poles established by phase B. The
effect of turning off phase B and energizing phase C is shown in
Figure 1.6 (c). In this circuit, the rotor has again moved 30° and is
now aligned under the north and south poles created by phase C. After
the rot or has been displaced by 60° from its starting point, the step
sequence has completed one cycle. Figure l.6 (d) shows the switching
sequence to complete a full 360° of rotation for a variable-reluctance
11
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
motor with six stator poles and four rotor poles. By repeating this
pattern, the motor will rotate in a clockwise direction. The direction of
the motor is changed by reversing the pattern of turning ON and OFF
each phase.
Figure 1.6
The VR stepper motors mentioned up to this point are all single-stack
motors. That is, all the phases are arranged in a single stack, or plane.
The disadvantage of this design for a stepper motor is that the steps
are generally quite large (above 15°). Multistack stepper motors can
produce smaller step sizes because the motor is divided along its axial
12
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
length into magnetically isolated sections, or stacks. Each of these
sections is excited by a separate winding, or phase. In this type of
motor, each stack corresponds to a phase, and the stator and rotor have
the same tooth pitch.
2.1.3 Hybrid Stepper Motors: The hybrid step motor consists of two
pieces of soft iron, as well as an axially magnetized, round
permanent-magnet rotor. The term hybrid is derived from the fact
that the motor is operated under the combined principles of the
permanent magnet and variable-reluctance stepper motors. The stator
core structure of a hybrid motor is essentially the same as its VR
counterpart. The main difference is that in the VR motor, only one of
the two coils of one phase is wound on one pole, while a typical
hybrid motor will have coils of two different phases wound on one
the same pole. The two coils at a pole are wound in a configuration
known as a bifilar connection. Each pole of a hybrid motor is
covered with uniformly spaced teeth made of soft steel. The teeth on
the two sections of each pole are misaligned with each other by a
half-tooth pitch. Torque is created in the hybrid motor by the
interaction of the magnetic field of the permanent magnet and the
magnetic field produced by the stator. Stepper motors are rated in
terms of the number of steps per second, the stepping angle, and load
capacity in ounce-inches and the pound-inches of torque that the
motor can overcome. The number of steps per second is also known
as the stepping rate. The actual speed of a stepper motor is
dependent on the step angle and step rate and is found using the
13
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
following equation:
2.3.4 Two-phase stepper motors:[11]
There are two basic winding arrangements for the electromagnetic coils in a
two phase stepper motor: bipolar and unipolar.
c. Unipolar motors
A unipolar stepper motor has logically two windings per phase, one for each
direction of current. Since in this arrangement a magnetic pole can be
reversed without switching the direction of current, the commutation circuit
can be made very simple (e.g. a single transistor) for each winding.
Typically, given a phase, one end of each winding is made common: giving
three leads per phase and six leads for a typical two phase motor. Often,
these two phase commons are internally joined, so the motor has only five
leads. A microcontroller or stepper motor controller can be used to activate
the drive transistors in the right order, and this ease of operation makes
unipolar motors popular with hobbyists; they are probably the cheapest way
to get precise angular movements. (For the experimenter, one way to
distinguish common wire from a coil-end wire is by measuring the
resistance. Resistance between common wire and coil-end wire is always
half of what it is between coil-end and coil-end wires. This is due to the fact
that there is actually twice the length of coil between the ends and only half
14
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
from center (common wire) to the end. Unipolar stepper motors with six or
eight wires may be driven using bipolar drivers by leaving the phase
commons disconnected, and driving the two windings of each phase
together. It is also possible to use a bipolar driver to drive only one winding
of each phase, leaving half of the windings unused.
Figure2.2.5
15
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
d. Bipolar motor
Bipolar motors have logically a single winding per phase. The current a
needs to be reversed in order to reverse a magnetic pole, so the driving
circuit must be more complicated, typically with an H-bridge arrangement.
There are two leads per phase, none are common. Because windings are
better utilized, they are more powerful than a unipolar motor of the same
weight.
Fig 2.2.6
16
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
2.2 Applications:As the sizes of Stepper Motor Varies, the uses and it's applications varies in
different ways. Specially in motion control position systems, Which follows the
open-loop theory (no feedback required). Briefly, Here is some areas where it is
used:
1- Office Equipments: Printers, Scanners and Optical disk drive.
2- Medical Equipments: digital dental photography, fluid pumps,
respirators, blood analysis machinery, chemically mixing machine.
Milling Machine[8]
Serial
Printer[9]
17
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
CHAPTER THREE
Practical Experiment
3.1 Introduction:
This chapter is mainly about our stepper motor driver using discrete component
simple and expensive which is available in any electronic shop. The experiment is
to connect theoretical part with practical part in order to make it more
understandable by my colleague.
In the next section you will find the circuitboard schematic with component's lists
and the driver operation, which implies the basic control function for the stepper
motor; such as: Forward, Reverse, Stop, Slower and Faster step rate are possible.
18
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
3.2 The Driver Circuit:
* [10]
19
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
3.3 Basic Stepper Motor Driver Operation:
1. The LM555 (IC 1) a stable oscillator produces CLOCK pulses that are fed to
PIN 11 of the 74194 (IC 2) shift register.
2. Each time the output of the LM555 timer goes HIGH (positive) the HIGH
state at the 74194's OUTPUT terminals, (PIN's 12, 13, 14, 15), is shifted
either UP or DOWN by one place.
The direction of the output shifting is controlled by switch S1. When S1 is in
the OFF position (centre) the HIGH output state will remain at its last
position and the motor will be stopped.
Switch S1 controls the direction indirectly through transistors Q2 and Q3.
When the base of Q2 is LOW the output shifting of IC 2 will be pins 15 - 14
- 13 - 12 - 15; .etc.
When the base of Q3 is LOW the output shifting of IC 2 will be pins 12 - 13
- 14 - 15 - 12; .etc.
The direction of the output's shifting determines the direction of the motor's
rotation.
3. The outputs of the 74194 are fed to four sets of paralleled segments of a
ULN2803 Darlington driver (IC 3).
20
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
When an input of a ULN2803 segment is HIGH, its darlington transistor will
turn ON and that OUTPUT will conduct current through one of the motors
coils.
4. As the coils of the motor are turned ON in sequence the motor's armature
rotates to follow these changes. Refer to following diagram.
21
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
3.4 Inputs Vs. Outputs Waveforms:
The following diagram shows the stepping order for the outputs of the ULN2803
(IC 3) as compared to the input and output of the 74194 (IC 2). The output is
shown stepping in one direction only.
22
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
3.5 Integrated Circuit Chips Used IC 1 - LM555 - Timer, normally configured as an stable oscillator but can be
used a monostable timer for 1 step at a time operation or can be used as a
buffer between external inputs and IC2. (See later Diagrams.)
IC 2 - 74194 - 4-Bit Bidirectional Universal Shift Register. The shift register
provides the logic that controls the direction of the drivers output steps.
IC 3 - ULN2803 - 8 Segment, Darlington, High Current, High Voltage
Peripheral Driver. Each segment can handle currents of up to 500 milliamps
and voltages up to 50 volts. In this circuit 2 output segments are connected
in parallel, this allows a maximum output current of 1 amp per phase.
IC 4 - LM7805 - Positive 5 Volt Regulator. Provides low voltage power to
the driving circuitry and can also power external control circuits.
23
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
3.6 74194 Stepper Motor Driver Notes: Due to the lack of error detection and limited step power, this circuit should
not be used for applications that require accurate positioning. (The driver is
designed for hobby and learning uses.)
There are links to other stepper motor related web pages further down the
page. These may be helpful in understanding stepper motor operation and
control.
For the parts values shown on the schematic, if the external potentiometer
(RT) is set to "ZERO" ohms, the calculated CLOCK frequency will be
approximately 145 Hz and a motor will make 145 steps per second. This
step rate should be slow enough for most motors to operate properly.
The maximum RPM at which stepper motors will operate properly is low
when compared to other motor types and the torque the motor produces
drops rapidly as its speed increases. Testing may be needed to determine the
minimum values for RT and C1 to produce the maximum CLOCK
frequency for any given motor. Data sheets, if available, will also help
determine this frequency.
If RT is set to 1 Mega Ω, the calculated step rate will be 0.73 Hz and the
motor would make 1 step every 1.39 seconds.
There is no minimum step speed at which stepper motors cannot operate.
Therefore, in theory, the values for RT and C1 can be as large as desired but
24
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
there are practical limitations to these values. The main limitation is the
'leakage' current of electrolytic capacitors.
External CLOCK pulses can also be used to control the driver by passing
them through IC 1 via the "T2" terminal of the circuitboard. Using IC 1 as
an input buffer should eliminate "noise" that could cause the 74194's output
to go into a state where more than one output is HIGH.
If stepping rates greater than 145 per second are needed, capacitor C1 can be
replaced with one of lower value.
A 0.47uF capacitor would give a calculated range of 1.5 to 310 steps per
second.
A 0.33uF capacitor would give a calculated range of 2.2 to 441 steps per
second.
Alternately, capacitor C1 can be removed from the circuitboard and an
external clock source connected at terminal 'T2'. With C1 removed, the
practical limit on the step rate is the motor itself.
In the above items the "calculated" minimum and maximum CLOCK
frequencies are valid for the nominal part values shown. Given the
tolerances of actual components and the leakage currents of electrolytic
capacitors the actual CLOCK rates may be lower or higher.
The direction of the motor can be controlled by another circuit or the parallel
output port of a PC. This will work as long as the voltage at the bases of Q2
25
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
and Q3 can be made lower than 0.7 volts. Additional NPN transistors may
be required to achieve this result, depending on the method used.
If the bases of both Q2 and Q3 are made LOW at the same time the
SN74194 will go into a RESET mode. This will cause the step sequence to
stop and on the next clock pulse pins 15 and 14 will go to a HIGH state.
Making the bases of both Q2 and Q3 LOW at the same time can be used to
reset the SN74194 to its starting position without having to remove the
circuit power.
Each stepper motor will have its own power requirements and as there is a
great variety of motors available. This page cannot give information in this
area. Users of this circuit will have to determine motor phasing and power
requirements for themselves.
Power for the motors can be regulated or filtered and may range from 12 to
24 volts with currents up to 1,000 milliamps depending on the particular
motor.
Motors that operate at voltages lower than 12 volts can also be used with this
driver but a separate supply of 9 to 12 volts will be needed for the control
portion of the circuit in addition to the low voltage supply for the motor.
A LED connected to the output of the LM555 timer (IC 1) flashes at the
CLOCK frequency. If a direction has been selected, The motor will move
one step every time the led turns ON.
26
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
There is no CLOCK output terminal on the circuitboard but there is a pad to
the right of the LED that can be used if a clock output signal is required.
This pad is connected to pin 3 of the LM555 IC.
The LM7805, positive 5 volt regulator used on the circuitboard can also be
used to provide power for external control circuits. With its tab trimmed off,
the regulator can easily dissipate up to 1 watt.
For a 12 volt supply, external circuits can draw up to 100 milliamps.
For a 24 volt supply, external circuits can draw up to 25 milliamps.
The photo of the circuitboard shows the tab of the 7805 regulator cut off,
this is an option that is available on request.
3.7 74194 Stepper Driver Initialization Notes:
When power is applied to the 74194 Stepper Driver circuit there is a very
short delay before stepping of the outputs can begin. The delay is controlled
by Capacitor C2, resistor R4 and transistor Q1.
The function of the delay is to allow the outputs of IC 2 to be set with pin 12
in a HIGH state and pins 13, 14 and 15 in a LOW state before direction
control becomes active. The delay also prevents IC 1 from oscillating until
IC 2 has been set.
27
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
If the power to the circuit is turned off, there should be a pause of at least 10
seconds before it is reapplied. The pause is to allow capacitor C2 to
discharge through R4 and D2.
If the initialization delay were not used, IC 3 could have: none, any or all of
its outputs in a high state when stepping is started. This would cause the
motor to move incorrectly or not at all during normal operation.
The stepper motor driver is ready to start operation as soon as the initialization
delay is complete.
3.8 Stepper Circuit Board Parts List:
Qty. Part # DigiKey Part # DigiKey Description
1 - IC 1 - LM555CNFS-ND - IC TIMER SINGLE 0-70DEG C 8-DIP
1 - IC 2* - 296-9183-5-ND - IC BI-DIR SHIFT REGISTER 16-DIP
1 - IC 3 - 497-2356-5-ND - IC ARRAY EIGHT DARLINGTON 18 DIP
1 - IC 4 - LM7805ACT-ND - IC REG POS 1A 5V +/-2% TOL TO-220
- - -
3 - Q1, 2, 3 - 2N3904FS-ND - IC TRANS NPN SS GP 200MA TO-92
1 - D1 - 160-1712-ND - LED 3MM GREEN DIFFUSED
1 - D2 - 1N4148FS-ND - DIODE SGL JUNC 100V 4.0NS DO-35
1 - D3 - 1N4001FSCT-ND - DIODE GEN PURPOSE 50V 1A DO41
- - -
4 - R1, 2, 8, 9 - 3.3KQBK-ND - RES 3.3K OHM 1/4W 5% CARBON FILM
3 - R4, 6, 7 - 10KQBK-ND - RES 10K OHM 1/4W 5% CARBON FILM
1 - R3, 5 - 470QBK-ND - RES 470 OHM 1/4W 5% CARBON FILM
- - -
1 - C1 - P5174-ND - CAP 1.0UF 50V ALUM LYTIC RADIAL
2 - C2, 3 - P5177-ND - CAP 4.7UF 50V ALUM LYTIC RADIAL
28
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
1 - C4 - P5168-ND - CAP 470UF 35V ALUM LYTIC RADIAL
- - -
4 - - ED1602-ND - TERMINAL BLOCK 5MM VERT 3POS
CHAPTER FOURConclusions
Stepper motors has played major part in the world of technology, it was and still a
huge invention for science of machine control system, as it was mention it was
used since 1919 at British Army and how it was improved until now days. This
report indicates the very basic of stepper motor and its theory, types and
application. It was a success in terms of getting control of the stepper motor. There
is a lot of room for improvement but the main goal was reached. The stepper motor
moved as seen in the experiment in both direction at different speeds and step pace
like the notes said it should.
29
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
References:[1] [2] [3] [4] [5] [6] [8] [9] Stepping Motors and their Microprocessor
controls, Takashi Kenjo Ed:1, Published 1984.
[7] Industrial Electronics, Colin D. Simpson, Published 2006.
[10] http://home.cogeco.ca/~rpaisley4/Stepper1200Proto.html
[11] WEB: Wikipedia
[12] Stepping Motors Fundamentals, Reston C. etal.
[13] Practical Electric Motor Handbook, Irving G., Ed: 1st 1997.
[14] Rotating Machinery: Practical Solutions to Unbalance and Misalignment,
Robert B. McMillan, 2004.
30
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
Appendices: Data Sheet
31
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
32
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
33
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
34
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
35
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
36
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
[1]
37
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
38
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
39
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
40
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
41
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
42
Fadel Hasan Ramadan Project II, EEE 450
07075933 Dr.Osama Al Rawi
BSC in Electrical Engineering
[2]
43