科技英语论文
uncommitted-
科技英语作业
郑州大学电气工程学院
自动化四班
丁相鹏
2
Recorded.
Abstract to.
The first
chapter design task requirements and solutions
1.1 task requirements
The overall scheme of
2.1 determination and component
selection.
The overall
design diagram.2.1.1
To determine the
2.1.2 control scheme
2.1.3 system
2.1.4 SCM
system
2.1.15 D/A conversion
2.1.5 thyristor control
Sensor 2.1.6
2.1.7 signal
amplifying circuit
2.1.8 A/D conversion
2.1.9 temperature setting and display
the second chapter system hardware
design
2.1 hardware system diagram
The analysis part of connection between
the 2.2 system
The third chapter system
software design
3.1. Program flow chart
The fourth chapter parameter
calculation
The design of each module
and parameter calculation system,
4.1.1 4.1 temperature acquisition and
conversion
4.1.2, the output signal of
the sensor amplifier circuit
4.1.3, ADC part: Design
4.1.4, ADC0804 chip peripheral circuit
4.1.5, numerical processing part and
the display part
4.1.6, PID. Algorithm
introduced
4.1.7, A/D
conversion module
4.1.8...... microcontroller basic
system debugging
4.1. 9 note
The fifth chapter test methods and test
results
Testing instruments and
equipment
5.1 system
5.2 test method
5.3 test results
The ending
References
Abstract
With the
development
of
national economy, people need to
monitor
and
control
the
temperature
of
medium
heating
furnace,
heat
treatment
furnace,
reaction
furnace
and
boiler.
MCU
to use them to control is not only easy to
control, simple
and
flexible
and
other
advantages,
and
can
greatly
increase
the
temperature
was
charged
with
the
technical
indicators,
which
can
greatly
improve
the
quality
and
quantity
of
products.
The
system
to
AT89C51,
AT89C2051
microcontroller
as
the
core,
including
sensor
temperature
acquisition,
A/D
mode
/
number
conversion,
single-chip
control,
digital
display
and
other
digital
part.
The
system
uses
PID
algorithm to
achieve
temperature
control
function,
through
the
serial
communication
to
complete
the
interaction
of two
pieces
of
SCM
information to achieve temperature settings,
control and
display. In order to
realize high precision temperature control,
the SCM system adopts PID control
algorithm and PWM pulse
width
modulation technology combined by controlling the
on
and power supply and a bidirectional
thyristor is disconnected,
thereby
changing the temperature of the heating time
method
to
achieve
control
of
water
temperature.
The
system
is
composed
of
keyboard
display
and
temperature
control
two
modules,
through
the
communication
module
to
complete
the
temperature
settings,
real
temperature
display,
water
temperature and other functions. It has
the characteristics of
simple circuit
structure, short program, high system reliability
and easy operation.
The first chapter task
requirements and the design scheme of
1.1 basic requirements
1.1.1
basic requirements:
A liter of water by
electric heating 1kW, the requirements of
water temperature within a certain
range can be set by hand,
and can
automatically adjust the temperature is lowered in
the
environment,
to
maintain
the
set
temperature
basically
unchanged. 1.1.2 index:.
This topic is to design a control one
litre water purification, the
heater
uses a kilowatt electric stove temperature setting
range
in
40-90
centigrade,
the
smallest
plot
divides
1
DEG
C,
the
temperature control static error is
less than equal to 1. (2) the
ambient
temperature to reduce the static error is less
than or
equal to 1 DEG C temperature
control. The actual temperature
decimal
digital display water. When the setting
temperature is
changed (from 40 DEG C
to a temperature of 60 DEG C), the
regulating
time
and
the
overshoot
of
the
system
are
reduced.
2.1 design
To
determine the overall scheme of the 2.1.1
The
block
diagram
of
the
overall
design
of
this
topic
are
as
follows:
Three
2..1.2 control methods
In
general, you can use the following several control
schemes:
(1) output switch control:
This
method
controls
the
output
state
by
comparing
the
deviation
between
the
given
value
and
the
controlled
parameter. But
because only two state control output, the rate
of
change
in
the
parameters
of
the
two
directions
are
the
biggest, so easily from
feedback loop oscillation,
On the automatic control system will
have a very negative
impact, and even
because of the frequent output switch can
not meet the system requirements for
control accuracy.
Therefore, this
control scheme is usually used in large inertial
system when the control precision and
dynamic characteristics
are not high.
(2) proportional integral plus derivative control
(PID control) characteristic of
proportional integral plus
derivative
control is due to the differential output and the
deviation change is proportional to the
speed controller, it has
obvious effect
on overcoming object capacity lag. On the basis
of the proportion plus the differential
action, the stability is
improved, and
the integral effect can eliminate the residual
error. Therefore, PID control is
suitable for large load change,
large
capacity lag, high control quality requirements
and
control system. Combined with the
requirements of this
example design
task, due to the transfer function of system is
difficult to obtain accurate
temperature in advance, it is
difficult
to determine what kind of control method can meet
the requirements of quality control
system. But from the
above analysis of
control methods, PID control method is the
most suitable for this case. On the
other hand, due to the MCU
control
process, regardless of which of the above control
method will not increase the cost of
hardware, but only need
to make the
appropriate changes to software implementation
of different control schemes.
Therefore, the system can use
PID
control mode to maximize the system to meet such
as
control accuracy, the most small
division, static error, and
other
control requirements. The composition of the
2..1.3
system because the project is a
typical detection and control
of
applications, it requires the system to complete
the water
temperature detection, signal
processing, input and output to
the
operation control of electric heating power in
order to
realize the whole process of
temperature control. Therefore, a
special computer application system
should be composed of
single-chip
microcomputer to meet the functional
requirements of detection and control
application types. In
addition, the use
of single-chip is also possible to realize the
intelligent control of temperature and
providing perfect
man-machine interface
and multi machine communication
interface, and these functions in
conventional digital logic
path is
often difficult to achieve or can not be achieved.
Therefore, this case uses the
microcontroller as the core of the
DDC
(direct digital control system). In this paper,
the control
part is mainly MCU control
and control circuit. Single chip
microcomputer control is achieved with
single-chip chip
control circuit is
part of the thyristor circuit to achieve the
implementation of part of the 1KW
electric furnace, the
feedback part is
the use of sensor technology. 2.1.4
microcontroller selection AT89C2051,
AT89C51
microcontroller is the most
commonly used microcontroller, is
a low
loss, high performance, CMOS eight bit
microprocessor.
AT89C2051 and MCS-51
Series MCU in the instruction system
and the pin is fully compatible, and
can make the system has
many MCS-51
series products no function, strong function,
high flexibility and low price. AT89S51
can constitute the real
MCU minimum
application system, reduce system volume,
increase system reliability, reduce
system costs. As long as the
program
length is less than 4K, four I/O ports are fully
available to support. Less intermediate
variables need to be
stored in the
system operation, but no need to expand the
external RAM. 2.1.6 power
amplifier2.1.7 sensor part
In this
project, the sensor will use the AD590 sensor.
Sensors
can be converted into
electricity temperature detection,
temperature measurement, control and
temperature signal
amplification,
transformation, etc. very convenient.
Temperature sensor types. Due to the
small thermoelectric
potential, the
thermocouple has low sensitivity; the thermistor
affects the precision due to
nonlinearity; the platinum
resistance
temperature sensor is seldom used in the small
system because of its high cost. AD590
is the two terminal
integrated
temperature sensor Analog America Devices
company, with the advantages of small
size, light weight,
good linearity and
stable performance etc.. The temperature
range of -50~+155 C 316LVM, full scale
error of 0.3 316LVM C,
when the supply
voltage is between 5~10V, the stability
degree is 1%, the error is only 0.01 C
316LVM, fully applicable
to the design
of the temperature measurement requirements.
In addition AD590 is temperature -
current sensor, to improve
the anti-
interference ability of the system is also very
helpful,
so this design uses AD590 as a
temperature sensor. Above and
the
subject of the measurement demand, so as to select
thermocouple temperature sensor. 2.1.8
signal amplification
amplifier circuit
Is the use of electronic component with
amplification
characteristics, such as
the transistor, the transistor plus the
working voltage, small changes in input
current change can
cause a larger
current output, the output changes to hundreds
of times larger than the input changes
several times, this is the
basic
principle of 2.1.9 amplifying circuit A/D
conversion
ADC0809 IN0 and amplifier
circuit output connected, so the
IN0
input 0V-+5V range analog voltage after A/D
conversion
by 8031 through the program
input from the P0 port to its
internal
RAM unit. First input address selection signal,
under
the action of ALE signal, address
signal is locked, produce
decoding
signal, select the analog input. Then enter the
start
conversion control signal START
to start the conversion. At the
end of
the conversion, the data is sent to the three
state buffer
latch and the EOC signal
is sent. Under the control of the input
signal OE, the conversion result is
input to the external data
bus. 2.1.10
set temperature and display part
The
third chapter hardware system design
2.1 system hardware diagram
This system is a typical closed-loop control
system, power
electric control
purposes, to control the characteristics of
thyristor by single chip technology, so
as to control the
voltage, and
ultimately achieve the power control of electric
furnace. In addition, the system also
has feedback device,
through the sensor
detection technology at any time the
temperature of water purification,
after processing feedback
to SCM
control part and display part display.
The 2.2 part system connection analysis
2.2.1 feedback feedback part is
composed of;
The sensor to the
amplifying circuit to A/D to MCU, the wiring
diagram is as follows:
AT89C51 microcontroller to control the
core, collected
temperature, amplified
and transformed by AD single-chip
processing, and then through the serial
port is sent to the
display module due
to the PID operation when you call the
floating-point arithmetic library,
application requires a lot of
storage
space, 8051 part can meet this requirement, so do
not
need external expansion ROM, the
only intermediate variable
for a given
temperature and measured to system operation,
PID operation of intermediate results
and output results of
more than a dozen
variables. Thus the 8051 chip RAM can
meet the requirements, it can not be
extended.
2.2.2 display part
Display
part is the interface between the microcontroller
and
keyboard and display circuit,
divided into digital display and
alarm
two parts, its wiring diagram is as follows: