C6: Control System and Micro Microprocesor

8/9/2019 C6: Control System and Micro Microprocesor

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6.0 Control system and

microprocessor

1. Input and output process and devices

2. Open and closed loop system

3. Modeling in frequency and time domain


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1.0 Microprocessors

Microprocessor is technically defined as a single-chipcentral processing unit (CPU) for a programmablecomputer.

Microprocessor (P) is the brain of a computer that has

been implemented on one semiconductor chip. A CPU may be considered to be the brain of a computer

because it understands and executes the sequence ofbinary instructions in a compiled computer program.

Compared to the CPU, the other parts of a computer arerelatively dumb and

require detailed attention from the CPU in order tofunction properly in the computer system.


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Microprocessors Related Terms

A microcomputer is a computer system that has been built

around a microprocessor chip.

A microcontroller is an integrated circuit that contains a

microprocessor as well as other useful support circuits,

such at timers, memory, input/output interface circuits, etc. The EE380 lab microcomputer system contains the

Motorola MC68332 microcontroller chip.

A digital signal processor (DSP) is a specialized

microprocessor that has features (e.g. instructions,registers, internal signal paths, arithmetic circuits) that make

it particularly efficient at performing the kinds of numerically

intensive calculations that are required in digital signal

processing (e.g. in modems and cell phones)


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Applications of Microprocessors

Microprocessors can be found just about everywhere: In general-purpose computers, like mainframes, personal

computers (PCs), and single-board computers (SBCs).

In special-purpose computers, like calculators, personal

data assistants (PDAs), and game computers. In embedded computers that control automobiles,

appliances, instruments, communication systems, cell

phones, factories, assembly lines, refineries and etc.

Ex. In a car: Microprocessors are used in the ignitionsystem, emission control system, anti-lock brakes,

dashboard display, entertainment system, navigation

system, etc. Modern cars often contain 20 or more

microprocessors.


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Microprocessors History

The microprocessor is made from advanced integrated

circuit technology where several thousand transistor

switches are integrated onto a single semiconductor

chip.

The Intel 4004 (1971) was the first microprocessor: originally developed for a desktop calculator product

contained 2300 transistors

occupied a silicon area of 12 mm2

implemented in 10 m PMOS semiconductor technology data bus was 4 bits wide

640 bytes of data could be addressed

system clock run at a frequency of 108 KHz

could perform roughly 60000 operations per second


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Microprocessors History (cont.)

Intel 4004

Was Intel's first

microprocessor.

It contained 2,300

transistors and was built

using a 10 micron

process.It had a total of 16 pins.


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Typical Interface

+5V

FX1

J4

C220pF

J1

FX2

TEST

+5V

J2

J3

C120pF

SCL

0.1C3

1

2

3

4

XP1

20.0MHzZQ1

SDA

22GND

28SCL

21NC

20VCC

13 SMPL

10OSC2

7VCC

4FX1

1NC

11ST2

12CE2/BN

14CHRG

8GND

5 FX26

ST1

9OSC1

2RXD

3TXD/IS1

16SS/TEST

19SCK/N2

25M1/A1

15CE1/BW

17MOSI/N0

18MISO/N1

24M0/A023

MES/BS

27SDA/IS0

26M2/A2

USTI

IC1


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The Intel Itanium entered mass production in 2001:

intended for high-end servers and workstations

contains 25.4 million transistors

silicon chip area exceeds 300 mm2

180 nm CMOS semiconductor technology

6 layers of metal interconnections

1012 chip pad connections

64-bit data bus; 64-bit address bus; 64-bit registers

memory space of over 18 terabytes (264 = 18.45 x 1018). system clock frequency of at least 800 MHz

peak performance of 3.2 billion instructions per second

The pace of technological progress shows no signs of slowing

down in the immediate years ahead . . .


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Pentium 4

42 million transistors and

circuit lines of 0.18 microns.

Intel's first microprocessor,the 4004, ran at 108

kilohertz (108,000 hertz),

compared to the Pentium 4

processor's initial speed of1.5 gigahertz (1.5 billion

hertz).


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Microprocessors Revolution

The appearance of the microprocessor revolutionized digital

system design starting in the 1970s, and continuing on until

the present day.

In recent times, almost all analogue controllers have been replaced by

some form of computer control.This is a very natural move since control can be conceived as the

process of making computations based on past observations of asystems behaviour so as to decide how one should change themanipulated variables to cause the system to respond in a desirablefashion.

The most natural way to make these computations is via some form ofcomputer.


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Input

Devices

ProcessingData into

Information

Output

Devices

ControlControl

UnitUnit

Secondary Storage Devices

Arithmetic-Arithmetic-

LogicLogic

UnitUnit

Primary StoragePrimary Storage

UnitUnit

Central Processing Unit

Keyboard

MouseTouch Screen

Voice...

Monitor

Printer

Disks, Tapes, Optical Disks

Basic Microprocessors System


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Basic Microprocessors System (cont.)

Basic microprocessor system consists of the

microprocessor core, memory, input/output modules,

and a system bus connecting these modules.

The memory system usually consists of Read Only

Memory (ROM) for boot information, and RandomAccess Memory (RAM) organized in a hierarchy of main

memory and multilevel cache memory.

Typically, the cache memory is implemented as level 1

cache closely coupled to the microprocessor core, andlevel 2 cache accessible over the system bus.

The main memory, typically DDR SDRAM, is accessible

over the system bus as well, but level 2 cache

(embedded SRAM) offers higher access speed.


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Basic Microprocessors System (cont.)

The microprocessor core contains a datapath section

(ALU and registers), a control section, and cache

memory.

Memory access rate varies according to the memory

hierarchy from 1 cycle access rate to registers and level

1 cache, to 10 cycles access rate to level 2 cache, up to

50 cycles access rate to main memory.

These are typical values and may vary from system to

system.


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Type Of Microprocessors

Computers based on a CPU with a complex

instruction set known as CISC (Complex Instruction

Set Computer) microprocessor

Intel

A RISC (Reduced Instruction Set Computer) has

limited set of instructions that it can perform quickly

AMD


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The Embedded Processor

A programmable processor whose programming interface

is not accessible to the end-user of the product.

The only user-interaction is through the actual application.

Examples:

Sharp PDAs are encapsulated products with fixed

functionality.

3COM Palm pilots were originally intended as

embedded systems. Opening up the programmers

interface turned them into more generic computer

systems.


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Disadvantages of Microprocessors

Microprocessors have many complex features.

Numerous features are provided to satisfy a wide

variety of users.

Microprocessors are completely unforgiving when

program errors are made. They will execute exactly

what is in the program, and have no common sense

or intuition about what the designer intended the

program to do.

Debugging tools for microprocessor assembly

language programs are usually primitive compared to

the tools available for programs in high-level

languages.


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Microprocessors Families

Microprocessor manufacturers tend to release microprocessors in

families of increasing complexity and performance

Intel Corp.:

4004 (1971), 8008 (72), 8080 (74)

x86 family: 8086 (78), 8088 (79), 80186 (82), 80286 (82), 80386(85), 80486 (89), Pentium (93), Pentium II (97), Pentium III (99),

Pentium 4 (2000), Xeon (2001)

IA-64 family: Itanium (2000),

Motorola, Inc.:

6800 family: 6800 (1974), 6809 (79), 68HC11 (84) M68000 family: 68000 (1979), 68010 (82), 68020 (84), 68030 (87),

68040 (89), 68332 (89), Power PC

Microprocessor families make it easier to carry software over from

an older P to the latest P. Upward compatibility is an important

strategy for building customer loyalty.


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6b.Open and closed loop system


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Feedback and Control

Sense

Compute

Actuate

Control =

Sensing + Computation +Actuation

Feedback Principles

Robustness to Uncertainty

Design of Dynamics

h i db k


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What is Feedback? Miriam Webster:

the return to the input of a part of the

output of a machine, system, or

process (as for producing changesin an electronic circuit that improve

performance or in an automatic

control device that provide self-

corrective action) [1920]

Feedback = mutual interconnection of two

(or more) systems

System 1 affects system 2 System 2 affects system 1

Cause and effect is tricky; systems

are mutually dependent

Feedback is ubiquitous in natural and

engineered systems

System 2

System 1

System 2System 1

System 2System 1

Closed

Loop

Open

Loop


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Magic of Feedback

Feedback is used to regulate the value of a quantity in a system to a desired level, by measuring the error, i.e.,difference between the desired value and the sensed value.

Sometimes the decision is based on the instantaneous value of error, and sometimes is based on the history ofthe error, and/or predictions on the future value of the error. Some times we use all three.

The performance of a feedback system is measured based on the response to a step change in the reference, or

in tracking a sinusoid.

Feedback regulation will work even when the components are uncertain.

The down side of using feedback is that

It can cause instability

It makes the design more complicated

The main components of a feedback loop are sensing, decision/computation, and actuation.

We will use theory of differential equations, linear algebra and complex variables to analyze feedback systems.


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Feedback (close-loop) Control

Actuator

Monitor

reference

control

input

controlled

variable

manipulatedvariable

Controlled System

+

-

error

controlfunction

Controller

sample


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Control design methodology

Controller

Design

Root-Locus PI

Control

RequirementAnalysis

Modeling

analyticalsystem IDs

Dynamic model Control algorithm

Performance Specifications

Satisfy


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6c. Input and Output


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Input/ Output Devices

The input/output (I/O)

devices of a computer are

not part of the CPU, but

are channels for

communicating between

the external environment

and the CPU.

Input devices deliver

data and instructions

into the computer.

Output devicesprovide

processing results.

I/O devices are subclassified

into the following categories;

Secondary storage

devices: primarily disk

and tape drives

Peripheral devices: any

input/output device that is

attached to the computer


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Secondary Storage

Secondary Storage is separate from primary storage and

the CPU, but directly connected to it. It provides the

computer with vastly increased space for storing and

processing large quantities of software and data.

Secondary storage media include; Magnetic tape

Magnetic disk

Magnetic diskette

Optical storage

Digital videodisk (DVD)


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Input Devices

Users can command the computer and communicate with it by

using one or more of the following input devices.

Keyboard. The most common input device is the keyboard.

The keyboard is designed like a typewriter but with many

additional special keys.

Mouse. The computermouse is a hand-held device used to

point a cursor at a desired place on the screen.

Touch Screen. The user activates an object on the screenby touching it with his or her finger.


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Input Devices (cont.)

Touchpad.A touchpadortrackpadis a small, flat,

rectangular pointing device that is sensitive to pressure and

motion.

Light Pen. A light pen is a special device with a light-sensing mechanism, which is used to touch the screen.

Joystick.Joysticks are used primarily at workstations that

can display dynamic graphics. They are also used in playing

video games. The joystick moves and positions the cursor atthe desired object on the screen.


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Input Devices (cont.)

Automated Teller Machines (ATMs).ATMs are interactive

input/output devices that enable people to obtain cash,

make deposits, transfer funds, and update their bank

accounts instantly from many locations.

Electronic Form. In form interaction, the user enters data or

commands into predesignated spaces (fields) in a form. The

headings of the electronic form serve as a prompt for the

input.

Whiteboard. A whiteboard is an area on a display screenthat multiple users can write or draw on.


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Source Data Automation

Source data automation captures data in computer-readableform at the moment the data are created.

Examples of Source Data Automation: Point-of-sale systems Optical bar-codes Code scanners Handwriting recognizers Voice recognizers

Magnetic ink character readers (MICR) Digitizers Digital Cameras


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Output Devices


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Output Devices (cont.)

Monitors

ImpactPrinters

Nonimpact

Printers Plotters

Voice Output

The output generated by a computer can betransmitted

to the user via several devices and media.


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System Models

Linearvs. non-linear (differential eqns)

Deterministic vs. Stochastic

Time-invariant vs. Time-varying

Are coefficients functions of time?

Continuous-time vs. Discrete-time

System ID vs. First Principle


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Dynamic Model

Computer systems are dynamic Current output depends on history

Characterize relationships among system variables Differential equations (time domain)

)()()()()( 01012 tubtubtyatyatya +=++

Transfer functions (frequency domain)Y(s) = G(s)U(s)

2

2

1

1

01

2

2

01)(

ps

c

ps

c

asasa

bsbsG

+

=

++

+

=

Block diagram (pictorial)

C(s)R(s) Y(s)-

G(s)


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Model differential equation

U(t)

Ra(t)

C?

Us-

CPU

Rc(t)

Model (differential equation): =

=t

ca dRRtU0

))()(()(

Error: E(t)=Us-U(t)

Controller C? E(t) Ra(t)


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Three ways of system modeling

A Diverge to MathSystem representations

u(t) g(t) y(t) ==

t

dutgtutgty0

)()()(*)()(

Time domain: convolution; differential equations.

U(s) G(s) Y(s) )()()( sUsGsY =

s (frequency) domain: multiplication

s-domain is a simple & powerful language for control analysis

Block diagram: pictorial


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Laplace transform of a signal f(t)

A Diverge to MathLaplace transform

==0

)()]([)( dtetftfLsF st

where s=+i is a complex variable. Laplace transform is a translation from time-domain to

s-domain Differential equation Polynomial function

)()()()()( 01012 tubtubtyatyatya +=++

)()(01

2

2

01sU

asasa

bsbsY

++

+

=


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Basic translations

Impulse function f(t)=(t) F(s)=1 Step signal f(t)=a1(t) F(s)=1/s

Ramp signal f(t)=at F(s)=a/s2

Exp signal f(t)=eatF(s)=1/(s-a) Sinusoid signal f(t)=sin(at) F(s)=a/(s2+a2)

Composition rules

Linearity L[af(t)+bg(t)] = aL[f(t)]+bL[g(t)]

Differentiation L[df(t)/dt] = sF(s) f(0-) Integration L[

tf( )d ] = F(s)/s

Laplace transform


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Transfer function

Modeling a linear time-invariant (LTI) system G(s) = Y(s)/U(s) Y(s) = G(s)U(s)

U(s) G(s) Y(s)

2

2

1

1

01

2

2

01)(

ps

c

ps

c

asasa

bsbsG

+

=

++

+=

E.g., a second order system withpoles p1 and

p2


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Poles and Zeros

The response of a linear time-invariant (LTI) system

=

=

=

=

++

+

=

=

+++

+++=

n

i

tp

i

n

n

i

n

i

i

m

i

n

n

n

n

m

m

m

m

i

eCtf

ps

C

ps

C

ps

C

ps

zsK

asasa

bsbsbsF

1

2

2

1

1

1

1

0

1

1

0

1

1

)(

...)(

)(

...

...)(

{pi} arepoles of the function and decide the system

behavior


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Time response vs. pole location

f(t) = ept, p = a+bj

UnstableStable


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Block diagram

A pictorial tool to represent a system based on transfer functions

and signal flows

Represent a feedback control system

C(s)R(s) Y(s)-

Go(s)

R(s) Y(s)Gc(s)

)()()(

)()(1

)()(

sRsGsY

sGsC

sGsC

G

c

o

o

c

=

+=


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Back toOur utilization control example

U(t)

Ra(t)

C?

Us-

CPU

Rc(t)

Model (differential equation): =

=t

ca dRRtU0

))()(()(

Error: E(t)=Us-U(t)

Controller C? E(t) Ra(t)


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ModelTransfer func. & block diag.

Inputs: reference Us(s) = U

s/s; completion rate R

c(s)

Close-loop system transfer functions U

s(s) as input: G

1(s) = C(s)G

o(s)/(1+C(s)G

o(s))

Rc(s) as input: G

2(s) = G

o(s)/(1+C(s)G

o(s))

Output: U(s)=G1(s)U

s/s+G

2(s)R

c(s)

ssG

s

sRsRsUdRRtU o

aa

t

ca

1)(

)()()())()(()(

0

=

== =

CPU is modeled as an integrator

Rc(s)

GoUs/sRa(s)

U(s)C(s)


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A huge array of control orientated computers are available in the marketplace.

A typical configuration includes:

some form of central processing unit (to make the necessary computations)

analogue to digital converters (to read the analogue process signalsinto the computer).

(We call this the process ofSAMPLING)

digital to analogue converters (to take the desired control signals outof the computer and present them in a form whereby they can beapplied back onto the physical process).

(We call this the process ofSIGNAL RECONSTRUCTION)


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What is frequency domain analysis ?

Analyzes the signals in the frequency space.

Primarily involves interpreting the spectrum.


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Typical analysis device


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Block diagram

i d f d i


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Time and frequency domain

measurement

M t it i


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Measurement criteria

It is important to know your approximate device length and use this value

to set your timebase appropriately. In general more time points around your

device will help bring out small or closely spaced discontinuities and will

improve reciprocity and other factors relating to over all measurement quality.


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the most accurate measurementis one with no variation and nodeviation (uncorrectable error)from the PNA value. These twocomponents provide a frameworkfor discussing how normalizing atvarious rise-times affect accuracy.

The dramatic increase in peak-to-peak variation in the figure ismostly due to the fact that

averages have been set relativelylow at 16, at 1024 averages(which would take significantlylonger for calibration &measurement)

Types of Control Orientated Computer


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Types of Control Orientated Computer

Depending upon the application, one could use many different forms

of control computer. Typical control orientated computers are:

DCS (Distributed Control System) These are distributed computer

components aimed at controlling a large plant.

PLC (Programmable Logic Controller) These are special purpose

control computers aimed at simple control tasks - especially thosehaving many on-off type functions.

PC (Personal Computer) There is an increasing trend to simply use

standard PCs for control. They offer many advantages including

minimal cost, flexibility and familiarity to users.

Embedded Controller. In special purpose applications, it is quite

common to use special computer hardware to execute the control

algorithm. Indeed, the reader will be aware that many commonly

used appliances (CD players, automobiles, motorbikes, etc.)

contain special microprocessors which enable various control

functions.


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Questions ?Questions ?

Wh i h ?


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What is the next wave?

C6: Control System and Micro Microprocesor

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Transcript of C6: Control System and Micro Microprocesor