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1、毕业设计(论文)中英文翻译原文系 别： 机电工程系 专 业： 机械设计制造及其自动化 学生姓名： 学 号： Based on SCM multi-functional temperature testing system design1 prefaceWith the development of society and the technological progress, people pay more and more attention to the importance of temperature detection and display. Temperature detecti
2、on and status display technology and equipment has been widely applied in industries, products on the market emerge in endlessly. Temperature testing and also gradually adopt the automatic control technology to realize the monitor. This topic is a temperature testing and status of the monitoring sys
3、tem.2 System solutionsThis system USES the monolithic integrated circuit AT89S52 as this system. The whole system, the hardware circuit including power supply circuit, sensor, the temperature display circuit circuit, upper alarm circuit such as shown in figure 1. Figure in the alarming circuit can b
4、e measured in upper temperature range, screaming voice alarm. The basic principle for the temperature control DSl8B20: when the temperature signal acquisition to after temperature signal sent to handle, AT89S52 temperature to LCD screen, SCM according to initialize the upper temperature setting, nam
5、ely, if the judgement of temperature than the highest temperature cooling fan is started, If the temperature is less than the lowest temperature setting on alarm device. Temperature controller diagram3 The system hardware design（1）AT89S52 SCM are introducedAT89S52 devices is a low power consumption,
6、 high CMOS8 bit micro-controller, 8K programmable Flash memory. Use Atmel company high-density nonvolatile storage technology, and industrial 80C51 product instruction and pin fully compatible. The Flash memory chips allows programs in system programming, also suitable for conventional programming.
7、In a single chip, have clever 8 bits CPU and programmable Flash in the system, for many embedded control AT89S52 application system provides a highly flexible, efficient solutions 5. AT89S52 has the following functions: the standard 256 bytes, 8k byte Flash RAM, 32 I/O port, the watchdog timer, 2 da
8、ta, three pointer 16 timer/counter, a 6 vector level 2 interrupt structure, full-duplex serial, timely clock circuit within crystals. In addition, 0Hz AT89S52 can drop to the static logic operation, support two software can choose power saving mode. Idle mode, the CPU to stop working, and allows the
9、 RAM, timer/counters, serial, continue to work. Protection mode, RAM by MCU, oscillator is frozen, all the work to stop until the next interruption or hardware reset.（2）The sensor DS18B20In the traditional analog signal distance temperature measuring system, need good solve lead error compensation,
10、multi-point measurement error and amplifying circuit switching technologies such as zero drift error problem, can achieve high measuring accuracy. Another general monitoring site of the electromagnetic environment is very bad, all kinds of jamming signal is stronger, the simulated temperature signal
11、 interference and vulnerable to produce measurement error and measuring precision 5. Therefore, in temperature measuring system, the strong anti-jamming capability of the new digital temperature sensor is the most effective to solve these problems, compared with other temperature sensor DSl820 has t
12、he following features:(1) the unique singleline interface way. DSl820 in connection with the microprocessor only need one interface to implement line DSl820 microprocessors and two-way communication. (2) more function simplifies distributed temperature detection application. (3) DSl820 in use withou
13、t any peripheral devices. (4) power, voltage range data available from 3.0 V to 5.5 V. (5) can measure temperature range from - 55 degrees c + + to 125, incremental value 0. 5 c, Fahrenheit temperature range from - 67 to + 257, incremental value 0.9. (6) support multi-point network function. Multipl
14、e DS1820 can pick on the same bus and, more temperature measurement. (7) 9 temperature resolution. Measuring results in nine serial transmission way the digital quantity. (8) user can set temperature alarm threshold. (9) have super temperature search function. DSl8B20 principle of workThe internal s
15、tructure of DS18B20 DSl8B20 temperature measurement principle diagram shown in figure 3.2. Low temperature coefficient graph oscillation frequency vibration product temperature is used to produce with fixed frequency, pulse signal to counter l. High temperature coefficient crystals temperature-depen
16、dent its oscillation frequency change significantly. The signal generated as the counter 2 input pulses. Counter 1, 2 and temperature registers are counter in - 55 degrees preset corresponding a base value. Counter l to low temperature coefficient of the pulse signal generated crystals, when the cou
17、nter for subtraction counting the preset value reduced to 1, when the temperature counter O value will add l, counter the preset value will be l man again, to counter the l start low temperature coefficient of crystal oscillator pulse signal, so cycle count until the counter 2, stop counting to O ac
18、cumulative temperature, temperature of the register for the register is measured values. Figure 3.2 accumulative used for the slope compensation and fixed temperature measurement, the output of the process of nonlinear correction is less than the preset value counter l. AT89S52 interface mode and DS
19、18B20Chip DS18B20 and the connection has two kinds: namely parasitic power and external power supply mode.Parasitic power way: in the parasitic power supply mode, the signal from the single chip DS18B20 in line drawing energy during the high level in the DQ energy stored in the internal capacitance,
20、 low level in signal in the energy consumed during the capacitance on working until high-level coming again to parasitic power (battery). Parasitic power mode has three advantages: 1) distance measuring temperature, without the local power supply. 2) no conventional power in the condition reads the
21、ROM. 3) circuit, with only one more concise root I/O realize temperature measurement. Want to make precise temperature conversion chip DS18B20, I/O line must ensure that the temperature conversion period, due to provide enough energy conversion in temperature during each DS18B20, when the current 1m
22、A to work a few temperature sensor in the same root hanging on the I/O multi-point temperature measurement, only by 4.7 K and resistance will not be able to provide enough energy, which cannot be switchover temperature or errors.The external power source supply way: in the external power supply mode
23、s, DS18B20 work power by VDD pin, I/O access line does not need strong pull up, there is no shortage of electricity power, can ensure accuracy and conversion in the bus theory can be articulated multiple sensor DS18B20, multipoint temperature measuring system.This system USES the external power sour
24、ce. Connection method is one foot grounding and DS18B20 2 feet (DQ) and AT89S52 foot an I/O port, 3 feet line up + 5V. A89S52 in the I/O port and + 5V connection between a 4.7 K pull-up resistors, to ensure the normal operation of the data collection. If you want to test system, composed multi-point
25、 temperature in the same root chip I/O port in the same line, and the method of connecting the parallel more pieces of DS18B20 chip.（3）LCD1602 LCD1602 LCD module can and monolithic integrated circuit AT89S52 directly interface.（4）Buzzer driver circuitDue to the working current buzzer is compared com
26、monly big, so I/O microcontroller is not directly driven by amplifying circuit, so it is generally used to drive, to enlarge current transistor. When the temperature is below six degrees Celsius, alarm.（5）Fan circuitWhen the temperature is higher than 80 c, start fan circuit. Because the job is grea
27、t, so use current amplifier circuit to drive, to enlarge current transistor. When the temperature is above 80 c, give a command, P2.6 single-chip microcontroller foot output level, triode conduction, fans, electric circuit, which began to turn it down.4 The design of the software systemThis system U
28、SES AT89S52 devices as the core, with DSl8B20 after the collected data, and the temperature inside the data storage AT89S52 deposit, LCD display, and compared with the prior value, and then the output signal by MCU control circuit and alarm circuit fan. Multi-functional temperature testing system so
29、ftware mainly include: function declarations, time delay function and DS18B20 initialization function, read the temperature, temperature DS18B20 data into a liquid crystal display characters such programs.5 SummaryWith the continuous development of industry of temperature measurement, the higher req
30、uirement, and more and more wide measuring range, so are the requirements for temperature detection technology more and more is also high.DSl8B20 introduced new digital temperature sensor and AT89S52 SCM, LCD1602 LCD module for constructing the temperature testing system. The hardware circuit and ma
31、in program and system design of each module subroutines. This system USES the DALLAS is the digital temperature sensor DS18B20, plus A/D can output the digital quantity, the temperature signal directly convert serial digital signal processing for microcomputer. Accordingly. This system has the hardw
32、are circuit structure is simple, high precision, and shows the result conversion clear stability, low cost and significant advantages. In temperature measurement, such as grain of intelligent building, central air conditioning of the occasion to temperature testing has good application prospects.The
33、 SCM and Vision21 Principle of MCUSingle-chip is an integrated on a single chip a complete computer system. Even though most of his features in a small chip, but it has a need to complete the majority of computer components: CPU, memory, internal and external bus system, most will have the Core. At
34、the same time, such as integrated communication interfaces, timers, real-time clock and other peripheral equipment. And now the most powerful single-chip microcomputer system can even voice, image, networking, input and output complex system integration on a single chip. Also known as single-chip MC
35、U (Microcontroller), because it was first used in the field of industrial control. Only by the single-chip CPU chip developed from the dedicated processor. The design concept is the first by a large number of peripherals and CPU in a single chip, the computer system so that smaller, more easily inte
36、grated into the complex and demanding on the volume control devices. INTEL the Z80 is one of the first design in accordance with the idea of the processor, From then on, the MCU and the development of a dedicated processor parted ways. Early single-chip 8-bit or all of the four. One of the most succ
37、essful is INTELs 8031, because the performance of a simple and reliable access to a lot of good praise. Since then in 8031 to develop a single-chip microcomputer system MCS51 series. Based on single-chip microcomputer system of the system is still widely used until now. As the field of industrial co
38、ntrol requirements increase in the beginning of a 16-bit single-chip, but not ideal because the price has not been very widely used. After the 90s with the big consumer electronics product development, single-chip technology is a huge improvement. INTEL i960 Series with subsequent ARM in particular,
39、 a broad range of applications, quickly replaced by 32-bit single-chip 16-bit single-chip high-end status, and enter the mainstream market. Traditional 8-bit single-chip performance has been the rapid increase in processing power compared to the 80s to raise a few hundred times. At present, the high
40、-end 32-bit single-chip frequency over 300MHz, the performance of the mid-90s close on the heels of a special processor, while the ordinary price of the model dropped to one U.S. dollars, the most high-end models, only 10 U.S. dollars. Contemporary single-chip microcomputer system is no longer only
41、the bare-metal environment in the development and use of a large number of dedicated embedded operating system is widely used in the full range of single-chip microcomputer. In PDAs and cell phones as the core processing of high-end single-chip or even a dedicated direct access to Windows and Linux
42、operating systems. More than a dedicated single-chip processor suitable for embedded systems, so it was up to the application. In fact the number of single-chip is the worlds largest computer. Modern human life used in almost every piece of electronic and mechanical products will have a single-chip
43、integration. Phone, telephone, calculator, home appliances, electronic toys, handheld computers and computer accessories such as a mouse in the Department are equipped with 1-2 single chip. And personal computers also have a large number of single-chip microcomputer in the workplace. Vehicles equipp
44、ed with more than 40 Department of the general single-chip, complex industrial control systems and even single-chip may have hundreds of work at the same time! SCM is not only far exceeds the number of PC and other integrated computing, even more than the number of human beings.Hardwave introduction
45、The 8051 family of micro controllers is based on an architecture which is highly optimized for embedded control systems. It is used in a wide variety of applications from military equipment to automobiles to the keyboard on your PC. Second only to the Motorola 68HC11 in eight bit processors sales, t
46、he 8051 family of microcontrollers is available in a wide array of variations from manufacturers such as Intel, Philips, and Siemens. These manufacturers have added numerous features and peripherals to the 8051 such as I2C interfaces, analog to digital converters, watchdog timers, and pulse width mo
47、dulated outputs. Variations of the 8051 with clock speeds up to 40MHz and voltage requirements down to 1.5 volts are available. This wide range of parts based on one core makes the 8051 family an excellent choice as the base architecture for a companys entire line of products since it can perform ma
48、ny functions and developers will only have to learn this one platform. The basic architecture consists of the following features: an eight bit ALU 32 descrete I/O pins (4 groups of 8) which can be individually accessed two 16 bit timer/counters full duplex UART 6 interrupt sources with 2 priority le
49、vels 128 bytes of on board RAM separate 64K byte address spaces for DATA and CODE memoryOne 8051 processor cycle consists of twelve oscillator periods. Each of the twelve oscillator periods is used for a special function by the 8051 core such as op code fetches and samples of the interrupt daisy chain for pending interrupts. The time requi
