1、外文文献资料Distributed Temperature Sensor1.Sensor introduction1.1 Temperature sensor backgroundIn the human living environment, temperature playing an extremely important role。No matter where you live, engaged in any work, ever-present dealt with temperature under. Since the 18th century, industry since
2、the industrial revolution to whether can master send exhibition has the absolute temperature touch. In metallurgy, steel, petrochemical, cement, glass, medicine industry and so on, can say almost eighty percent of industrial departments have to consider the factors with temperature. Temperature for
3、industrial so important, thus promoting the development of the temperature sensor. 1.2 Temperature sensor developmentMajor general through three sensor development phase: analog integrated temperature sensor. The sensor is taken with silicon semiconductor integrated workmanship, therefore also calle
4、d silicon sensor or monolithic integrated temperature sensor. Such sensing instruments have single function (only measuring temperature), temperature measurement error is smaller, price low, fast response, the transmission distance, small volume, micro-consumption electronic etc, suitable for long d
5、istance measurement temperature, temperature control, do not need to undertake nonlinear calibration, peripheral circuit is simple. It is currently the most common application at home and abroad, an integrated sensor。Typical products have AD590 AD592, TMP17, LM135, etc.jAnalog integrated temperature
6、 controller. Analog integrated temperature controller mainly include temperature control switch, programmable temperature controller, a typical product have LM56, AD22105 and MAX6509. Some increase strength type integrated temperature controller (for example TC652/653) also contains the A/D converte
7、r and cure good sequence, this process with the intelligent temperature sensor some similarities. But it is not its system, work by micro processing device control, this is the main difference between. Intelligent temperature sensor. intelligent temperature sensor (also called digital temperature de
8、grees sensor) is in the mid 1990s launch. It is microelectronics technology, computer technology and the dynamic testing technology (ATE) crystallization. Intelligent temperature sensor internal contain temperature sensor, A/D converter, signal processor, memory (or registers) and interface circuit.
9、 Some products still take multiplexer, central control system device (CPU), random access memory (RAM) and read only memory (ROM). Intelligent temperature sensor is characteristic of temperature data and relevant can output the temperature control of the quantity, adaptation various micro controller
10、 (MCU);1.3 Single point and more temperature sensorThe development trend of the temperature sensor. In the 21st century, the temperature sensor is headed in high precision, multi-function, bus, standardization, high reliability and safety, development of virtual sensor and network sensor, research m
11、onolithic temperature measuring system and other high-tech direction develop rapidly. Sensors in the application temperature controlling system. Current market exists mainly single point and more two temperature measurement. For single point temperature foundment instrument, mainly adopts the tradit
12、ional analog integrated temperature sensor, which heat resistance, thermocouple sensors measuring accuracy, high measurement range, and got the general application. This product is temperature measuring range 200 mostly between 800 , resolution 12th, and least distinguishable temperature in 0.001 0.
13、01 between. Cabin LED display module, shows ranging from 4 to 16. Some instruments also has memory function, can store several hundred to a few thousand sets of data. This instrument can be very good meet a single user single-point measurement needs. More temperature measurement, relative and single
14、 point measurement precision has certain gap, although realized the multi-channel temperature measurement and control, but the price is expensive. In view of the present market situation, proposed this topic can satisfy requirements, scalable and cost-effective single-chip multi-channel temperature
15、measuring system. Through the first temperature sensor DS18B20 acquisition, and then through the C51 SCM processing and displayed on the digital tube, can be collected indoor or a greenhouse around in different locations of the temperature, with four digital tube to display. The first digital pipe d
16、isplay acquisition is which way, which channel. Three digital pipe display after the acquisition channel by temperature, accurate to 0.1 degrees.2. The system realized and related technologies2.1.The system is realizedBy the whole control system for core AT89C51, using four ways of temperature senso
17、r DS18B20 in production site for distribution area of four different temperature measurement result with the chip checking, collation store and display, and through the button control, temperature will process after the LED digital display to come out, and the software assurance system anti-interfer
18、ence capacity。four DS1820 connected to MCU respectively, this scheme four IO mouth occupy MCU four IO though, but the microcontroller IO mouth under the condition of mouth not shortage by this scheme greatly simplify programming difficulty, shorten the design cycle, also can guarantee the stability
19、of the system. A multipoint connection as shown“1-1”DS1820DS1820DS1820DS1820AT89C51MCUP1.0P1.1P1.2P1.3P3.4Display elementButton control unit1-1 multipoint connection2.2 .AT89C51 Chip introductionAT89C51 is a 4K bytes FLASH Memory (Erasable Programmable and FPEROM - FLASH for the campaigns with) low
20、voltage, high-performance CMOS eight microprocessors, commonly known as the microcontroller. AT89C2051 is a 2K bytes with flash memory can be erased programmable read-only memory , SCM can erase read-only memory can be repeated erased 1000 times. This device adopts ATMEL high-density non-volatile me
21、mory manufacturing technology manufacturing, and industrial standard MCS - 51 instruction set and output tube compatible. Due to the multifunctional 8 bits CPU and will be flashing on single chip combination of memory, ATMEL AT89C51 is a kind of high efficient micro controller, AT89C2051 is a stream
22、lined version. AT89C 51microcontroller as many embedded control system .Arrange appearance and pin as shown in figure 1-2 shown1-2 AT89C51 pins figureMajor features: and MCS - 51 compatible 4K bytes programmable FLASH memory life: 1000 write/wipe cycle data retention time: 10 years the static job: 0
23、Hz - 24MHz level 3 program memory lock 128 x 8 bits internal RAM 32 programmable I/O lines two 16 timer 5 interrupt source programmable serial channels low power consumption of idle and power lost mode piece inside oscillator and clock circuitTube feet explains:VCC: power supply voltage.GND: grounde
24、d.P0 Mouth: P0 mouth a eight leak level two-way I/O mouth open, every foot can absorb 8TTL gate current. When the pipe mouth P0 feet first write 1, defined as high resistance input. P0 can be used for external program data storage, it can be defined as the eighth data/address. In FIASH programming,
25、P0 mouth as the source-code input port, when FIASH check, the source-code P0 output, when P0 external must be pulled.P1 mouth: mouth is an internal P1 provide pull-up resistors 8-bit two-way I/O mouth, P1 mouth buffer can receive 4TTL gate current output. P1 mouth tube feet, was then write 1 for hig
26、h, pull up inside can be used as input, P1 mouth be external pull down for low electricity at ordinary times, will output current, this is due to internal pull up sake. In FLASH programming and calibration, P1 mouth as eighth address to receive.P2 mouth: for an internal P2 mouth on the 8-bit pull-up
27、 resistors two-way I/O port, P2 mouth to receive, the output buffer 4 TTL gate current, when P2 mouth is written 1, its tube feet are internal pull-up resistors, and push as input. And so as the input, P2 mouth feet are external down tube, will output current. This is due to internal pull up sake. P
28、2 mouth when used external program memory or 16 address external data memory access, P2 mouth high output address eight. In a given address 1, it using internal and external 8 address advantage, when for reading and writing data memory, P2 when the special function registers mouth output of content.
29、 P2 mouth in FLASH programming and the calibration eight address when receiving high signal and control signals.P3 mouth: P3 mouth pipe is 8 feet with internal pull-up resistors two-way I/O port, may receive four TTL gate current out put. When P3 mouth writing 1, they are internal and high level, an
30、d used as input. As input, due to external drop-down for low level, P3 mouth will output current (ILL) this is due to pull ups sake.RST: reset input. When oscillator reset device to keep RST feet high level two machine cycle time.ALE/PROG: when access external storage, address latch allows the outpu
31、t level of the position for latch address byte. During the FLASH programming, this pin for input programming pulse. In peacetime, the ALE with a constant frequency cycle output is the pulse signal, the frequencies of the 1/6 oscillator frequency. So it can be used against external output pulse or us
32、ed for timing purpose. However it is: whenever used for external data storage, will skip a ALE pulse. If you want to ban the ALE output can be in SFR8EH address for 0. At this time, only by performing the ALE MOVX, MOVC instruction is ALE to take effect. In addition, the pins were slightly up. If mi
33、croprocessor in external execution ALE, buy a ban is invalid./ PSEN: external program memory choice of communication number. By external program memory in during the instruction fetch, each machine cycle twice /PSEN effective. But on a visit to external data storage, the two effective/PSEN signals w
34、ill not appear./ EA/VPP: when/EA keep low levels in this period, the external program memory (0000H - FFFFH), whether have internal program memory. Note encryption method 1, / EA will RESET for internal focus; When/EA end keep high electricity at ordinary times, internal program memory here. During
35、the FLASH programming, this pin is also used VPP 12V programming power (on).XTAL1: the inverting oscillator amplifier input and input to the internal clock operating circuit.XTAL2: from reverse oscillator output.2.3.DS18B20 Chip introductionDALLAS latest digital temperature sensor DS18B20 profile ne
36、w 1-wire devices smaller, wider and voltage applied to the DALLAS semiconductor company more economic DS1820 digital temperature sensor is the world the first piece of support 1-wire bus interface temperature sensor. 1-wire bus unique and economic characteristics, the user can easily form sensor net
37、work for measuring system, the construction of a new concept introduction. DS18B20 1-wire bus with DS1820 digital temperature sensor DS18B20 also support as 1-wire bus interface, measuring temperature range for - 55 C + 125 C, in - 10 + 85 C range, precision C for + 0.5. Scene in 1-wire bus temperat
38、ure directly the digital mode, can greatly improve the system of anti-jamming.Suitable for the scene in the bad environment temperature measurement, such as: environment control, equipment or process control, temperature measurement of consumer electronics, etc. And the previous generation product i
39、s different, the new product support 3V 5.5 V voltage range, make the system design more flexibly and conveniently. But a new generation of products cheaper, smaller. DS18B20 can program sets 9 12 resolution, precision C for + 0.5. Optional smaller encapsulation way, more wide voltage range. Resolut
40、ion setting, and users set alarm temperature EEPROM, stored in power lost and still save. DS18B20 performance is the best product of new generation! Performance to price also is very good!DS18B20 New performance:(1) data available supply, voltage range: 3.0 5.5 V;(2) temperature measuring range: - 5
41、5 + 125 in - 10 + 85 to + 0.5 when precision;(3) programmable resolution for the 9 12, the corresponding can distinguish respectively , the temperature of 0.5 and 0.125 , by 0.25 0.0625 ;(4) 12 resolution in most 750ms temperature into digital within;(5) negative pressure characteristics: power at t
42、he polarity, thermometers wont because when heating and burned, but cant work normally.DS18B20 Appearance and internal structure: DS18B20 internal structure consists mainly of four parts: 64-bit photolithography ROM, temperature sensors, nonvolatile temperature alarm triggers TH TL, configuration an
43、d registers. DS18B20 tube feet arrangement is “1-3”， internal structure is“1-4”1-3 DS18B20 tube feet arrangement (1) DQ for digital signal input/output terminal;(2) GND for power;(3) VDD for external power supplies input (in parasitic power connection mode grounding).1-4 internal structure3. Debug s
44、imulation 3.1.ProtuesProteus is Labeenter electronics company research UK EDA software. Proteus is not only the analog and digital circuit, d/a hybrid circuit design and simulation platform, but also is currently the worlds most advanced, the most complete various types of micro controller system de
45、sign and simulation platform. It really realized complete on computer schematic design, from circuit analysis and simulation and single-chip microcomputer and grade debugging and simulation, code system test and functional verification of the PCB formation to complete the design and development proc
46、ess of electronic. Proteus product series also contains a revolutionary VSM technology based on micro control, can the design with all peripheral electronic device simulation together. First start Proteus and Proteus components from the library selection need drawing diagram and set component, the c
47、orresponding element parameter values3.2. KeilcKeil Vision 2 is about the 8051 series MCU Keil company of development tools can be used to compile C source code, assemblers source program, connection and relocation target files and libraries, gen built: documents, debugging purposes procedure, etc,
48、it is a kind of integration of document management compile environment. It integrates document editing processing, compile connection, project management, window, tools cited and software copy true debugging and other functions, is pretty powerful development tool. In keil inside compile, the proced
49、ures required commissioning3.3. alignment(1) detection TCP/IP.(2) duplicate the Proteus installation directory vdm51. Who folder keilc/C51 / DLL to bin directory. (3) modify the installation directory Keil tools. TDRV4 = BIN, add the DLL. VDM51. (4) in the schematic drawing Proteus, in Debug menu, select Use Remote Debug
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