The principle of sensor of a few kinds of commonly used temperature reachs development

1 foreword science and technology cannot leave to measure. Metrical purpose should obtain the information of the concerned physics of the object that be measured or chemistry namely, so that to be being measured according to these information the object undertakes evaluate or be controllinged, the parts of an apparatus that fulfils this one function is sensor with respect to what we say. The forward position that sensor is IT is most advanced product, be used extensively at production of industry and agriculture, science studies and be born to wait for a domain, especially temperature sensor, scope of application is wide, the amount is much, first what reside all sorts of sensor. The development of temperature sensor was experienced roughly the following the sensor of schism type temperature of tradition of 3 phase;(1) (contain sensing element) ; basically is to be able to make is not be changed between n and n. (2) imitate is compositive temperature sensor / sensor of temperature of controller;(3) intelligence. Current, on international new-style temperature sensor from imitate type to digital type, can change by compositive Hua Xiangzhi, the way of network develops. The method of classified sensor classification of 2 sensor is very much, have 2 kinds of: commonly usedly? Before extensive pledges before hesitating badger seeks extensive of a flat stone on iron rammer with ropes attached at the sides of  of Zheng asking  to pledge does Fa of Xi brightness  beat frame M ǔ does Mou Wen  beat 0 hesitating badger cast Bo  evil spirit does げ of the skirt that treat  ask? temperature, specific heat, pressure, discharge, fluid? Does uranous Yu of ⒓ of Α of grey Pi ⒘ take: of parameter of sex of content of? of ⒅ Qi Kang? Does ǘ of army Chu ⑴ take ⑺ to weary: of parameter of amount of magpie? status? Does Lu of ニ of ⒛ of Pi of salt of ⒘ of  of a unit of length take N to show however does げ of skirt of brighting a surname of  dispute have a nightmare ask  N dew however does  dispute Da achieve scull of Tun of hesitating of Yi of  dispute Yong solid admire oh does シ wring charming evil spirit to treat kinds of is? big: ? Shine Suo wall oh ナ litter is shown however  of  dispute sole shine Suo owes a wall oh ナ litter is shown however  of  dispute sole oh ナ litter dew however  dispute Jian seeks a crusty pancake Xin Jimei of  of large bamboo hat of charm of error of hesitating of radon of summary   is graceful Ran oh ィ  ü .

The sensor of schism type temperature of 1 tradition, sensor of thermocouple sensor thermocouple is industry the sensor of a kind of temperature with the widest application in measuring, it is contacted directly with the object that be measured, do not suffer the effect of intermediate medium, have taller accuracy; to measure range wide, but from - 50 ℃ - 1600 ℃ undertake be metricaled continuously, special thermocouple is like Jin Tie - nickel is chromic, lowest can be measured - 269 ℃ , tungsten - rhenium is highest can amount to 2800 ℃ . Thermocouple sensor basically works according to pyroelectricity effect. two kinds different conductor A and B join rise, composition closes loop, make feeling lukewarm component namely, if pursue,1 is shown. Two contact when conductor A and B 1 and 2 between when existence difference in temperature, both between produce electromotive force, form the electric current of certain size in loop consequently, this kind of phenomenon calls pyroelectricity effect namely, also call thermoelectricity effect. Thermocouple uses this one effect to have the job namely. The one aspect of the matter of thermocouple is A, B two kinds of conductor solder together, call working end, in the medium be measuringed that park temperature is T. Another end calls ginseng comparing end or free end, those who be put at temperature to be T0 is constant below temperature. When the temperature of the medium that be measured that the job carries produces change, pyroelectricity situation produces change subsequently, will hot electromotive force sends the computer to undertake handling, can get temperature is worth. The pyroelectricity power difference of two end can use thermocouple next type represent: EIn T=E(t)-E(t0) type: ET, the pyroelectricity situation E(t) of thermocouple, the pyroelectricity situation E(t0) when temperature is T, the pyroelectricity situation when temperature is T0 should join the temperature that compares end when T0 is constant, heat up the temperature that electromotive force carries at the job only to concern, namely Et=f(t) . When the material of the hot electrode that should comprise thermocouple is even, its heat up the size of electromotive force and the length that heat up electrode itself and diameter to have nothing to do, reach the temperature of two end to concern with the composition of hot electrode only. 3.

2 compositive (IC) temperature sensor (1) imitate is compositive temperature sensor is compositive sensor is to use silicon semiconductor compositive craft and those who make, because this also calls silicon sensor or sheet piece compositive temperature sensor. Imitate is compositive in 20 centuries 80 time come out temperature sensor, it is temperature sensor compositive go up in a chip, achievable temperature measures the special IC that reachs imitate signal to output a function. Imitate is compositive the main characteristic of temperature sensor is a function onefold (measure temperature only) , measure lukewarm error small, price is low, answer speed fast, transmission distance far, bulk is small, small power comsumption, suit remote measure lukewarm, accuse to measure, do not need to undertake nonlinear calibration, periphery circuit is simple. A kind of when still applying generally domestic and internationally at present compositive sensor, the IC temperature sensor that one kind introduces to have tall sensitivity and high accuracy below, AN6701. If the graph is shown 2 times,the principle of AN6701 pursues, it is detected by temperature 3 parts comprise circuit, temperature compensation circuit and buffer amplifier. Of IC temperature sensor detect circuit is to use transistor to blast off to two extremely current density difference produces base - blast off extremely the voltage between is poor (the principle of VbC) and of the job. The graph is shown 3 times detect for temperature reach temperature to amend circuit plan. Graph 2 in, t1-T5 is detect circuit, t8-T11 and the circuit generation direct ratio that RC comprises its are absolutely the electric current of temperature, this electric current passes T12 and T13 infuse T7, can obtain correspondence the compensation temperature at infuse electric current. RC is outside receive resistor, make the calibration of sensor more convenient. (Sensor of sensor of 2) intelligence temperature (also call digital temperature sensor) be in 20 centuries 90 time metaphase comes out. It is microelectronics technology, computer technology and automatic test technology (the crystallization of ATE) . Current, products of a variety of series of intelligent temperature sensor already were developed on international. Interior of intelligent temperature sensor includes processor of converter of temperature sensor, A/D, signal, memory (or register) with interface circuit. Some products still take multichannel selector, central controller (memory of CPU) , random access (RAM) and read-only memory (ROM) . The characteristic of intelligent temperature sensor is to be able to export temperature data and relevant temperature control quantity, comfortable match all sorts of small controller (MCU); and it realizes test function on the foundation of hardware through software, its intelligence changes harmony to also depend on the development level of software. The new trend that sensor of 4 intelligence temperature develops after 21 centuries, intelligent temperature sensor forward standardization of high accuracy, muti_function, bus line, high reliability and security, development is fictitious sensor and network sensor, development is single a way that measures the high-tech such as lukewarm system is quick develop. 4.

1 rise measure lukewarm precision and resolution the intelligent temperature sensor that 90 time metaphase rolls out 21 centuries the earliest, those who use is 8 A/D converter, its measure lukewarm precision inferior, resolution can achieve 1 ℃ only. Current, abroad already rolled out the intelligent temperature sensor of a variety of high rate, high resolution in succession, what what use is 9 ～ 12 A/D converter, resolution can be amounted to commonly 0.

5 ～ 0.

0625 ℃ . By sensor of temperature of intelligence of the DS1624 of new development of company of American DALLAS semiconductor high resolution, can output data of 13 binary systems, its resolution is as high as 0.

03125 ℃ , measure lukewarm precision to be ± 0.

2 ℃ . To raise the changeover rate of sensor of temperature of much passageway intelligence, also some chip use high speed successive to approach type A/D converter. It is with sensor of temperature of intelligence of AD7817 5 passageways exemple, its changeover time to sensor of Cheng of this locality sensor, each great distance is 27 μ S, 9 μ S only respectively. 4.

The 2 test functions that increase sensor of test function temperature also are increasing ceaselessly. For example, sensor of temperature of DS1629 single-track intelligence increased clock of real time calendar (RTC) , make its function more perfect. DS1624 still increased memory function, use chip interior the E2PROM memory of 256 byte, can store the short message of the user ceases. Additional, intelligent temperature sensor is developing to the direction of much passageway from only channel, this is measured to develop and develop multichannel temperature accused a system to create good condition. Sensor has a variety of job mode to be able to offer an alternative, basically include odd second changeover mode, successive changeover mode, bide one's time mode, some still raised microtherm limit patulous mode, the operation is very handy. To sensor of certain intelligence temperature character, lead plane (exterior microprocessor or odd a machine) still can come through corresponding register its A/D changes set rate (typical product is MAX6654) , resolution and time of the greatest transition (typical product is DS1624) . 4.

The bus line technology of the standardization of technology of 3 bus line and sensor of standardization intelligence temperature also realized standardization, standardization, what use bus line to basically have single track (1-Wire) bus line, I2C bus line, SMBus bus line and SPI bus line. Temperature sensor serves as from machine can have communication through interface of special bus line and lead plane. 4.

4 dependability and converter of security design D use integral formula mostly or successive compares type to change a technology, its noise tolerance is low, restrain mix fold noise and the ability that quantify noise to compare difference. Sensor of new-style intelligence temperature (for example TMP03/204, LM74, LM83) used high-powered ∑ generally - converter of Δ type A/D not only can filter is divided quantify noise, and because low to the precision requirement of periphery component; uses digital feedback means, because the maladjusted voltage of this comparator is reached,zero shift won't affect the changeover precision of temperature. Temperature sensor holds this kind of intelligence concurrently to control capacity of the interference that string together a model strong, resolution tall, degree of linearity good, cost is low advantage. Be in to avoid lukewarm misoperation of the generation when accusing a system to be disturbed by noise, the interior of intelligent temperature sensor waits in AD7416/7417/7817, LM75/76, MAX6625/6626, installed a programmable " queue with balking (Fault Queue) " tally, special allow value of the temperature that be measured to go up more than at set, the frequency of floor level. When the 4) of frequency N(n=1 ～ that exceed upper limit continuously when the temperature that be measured only or exceeds a set under the frequency of floor level, ability sparks interrupt end. If breakdown frequency does not satisfy afore-mentioned conditions or breakdown,do not happen continuously, breakdown tally with respect to restoration won't spark interrupt end. This is meant assume when N=3, so accidental get or twice noise is disturbed, won't affect lukewarm the regular job that controls a system. 76 model intelligent temperature sensor increased temperature window comparator, suit to design to accord with ACPI(Advanced Configuration And Power Interface very much, namely " advanced configuration and power source interface " ) normative lukewarm control a system. This kind of system has perfect overheat to protect a function, can use monitoring notebook computer and the temperature of the CPU in the server and main circuit. Microprocessor is highest but regulation of susceptive job temperature is TH, table computer is 75 ℃ commonly, the special CPU of high-grade notebook computer can amount to 100 ℃ . Once the temperature of CPU or main circuit exceeds a set go up, when floor level, INT end makes lead plane generation is interrupted instantly, controller of repass power source issues signal, rapid will advocate power source closes to rise to protect action. In addition, when temperature exceeds the limiting temperature of CPU, serious overheating calls the police output is carried (T_CRIT_A) also can close directly advocate power source, and this end still can pass independent hardware judge circuit to cut off advocate power source, in case advocate electric source control is out of order. Afore-mentioned ternary security safeguard already made the new sense that thermometry establishs to control a system on international. Discharge to because human body is electrostatic,prevent (ESD) and attaint chip. Sensor of temperature of a few intelligence still increased ESD to protect circuit, can bear commonly the electrostatic spark voltage of 1000 ～ 4000V. It is normally body equivalent at by 100pF capacitance 1.

The circuit model that 2k Ω resistor establishs ties and becomes, when human body discharges, the serial interface end of sensor of TCN75 intelligence temperature, interrupt / end of comparator signal output and address input end all can bear the electrostatic spark voltage of 1000V. Sensor of LM83 intelligence temperature can follow the electrostatic spark voltage of 4000V. The intelligent temperature sensor of newest development (for example MAX6654, LM83) still increased sensor breakdown to detect function, can detect automatically sensor of exterior transistor temperature (sensor of Yi Chenyuan Cheng) open circuit or short circuit breakdown. MAX6654 still has a choice " check impedance is quits " (Parasitic Resistance Cancellation, english abbreviate is PRC) mode, place of impedance of down-lead of can quits long-range sensor causes measure lukewarm error, although down-lead impedance achieves 100 Ω , also won't affect measure precision. Long-range sensor down-lead can use common double skeining thread to perhaps take the double skeining thread of screen layer. 4.

Sensor of 5 fictitious temperature and network temperature sensor are fictitious sensor is to be based on sensor hardware and computer platform, be developed through software and become. Use software the demarcate of achievable sensor and calibration, in order to achieve optimum behavior target. Recently, pathogeny B&K company already developed a kind of TEDS that is based on software setting fictitious sensor, its are main the characteristic is every sensor has exclusive product serial number and accessary a piece of floppy disk, the memory on floppy disk wears what undertake demarcate to this sensor to concern data. When using, sensor is collected through data implement receive to the computer, input the product serial number of this sensor from the computer above all, numerate from floppy disk again concerned data, of parameter of the inspection that completes pair of sensor automatically next, sensor read take, sensor setting and record job. 5 last words rise ceaselessly as what industry manufactures efficiency, expand of automation level and limits ceaselessly, taller and taller also to the requirement of temperature sensor, baconian rise have the following sides: LPatulous measure lukewarm limits: ? Mei of S of party of housing Ang ひ seeks ℃ of?200 of  of crusty pancake a section of a highway - 3000 ℃ , as industrial development, ask to the measurement of superhigh temperature, ultralow temperature more and more pressing, if be in space rocket technology,often often need to measure thousands of degrees high temperature. Does L rise measure precision: ? Does  of wood of Qian Miao of a flat stone on iron rammer with ropes attached at the sides of  of glutinous of lotus root of  of stalk of ⒄ of Mu of Xi of aurelian border of widow Nuo Qian throw laborious to rip Jiao Shan to suckle graph of spruce ⑿ of fish hawk of Tuo of Gou Lu  to attack channel of Meng of A Chinese-style unlined garment of Qian  neon  of sparrow of  of a stone needle used in acupuncture in ancient China of  of Mu of Nuo of pregnant lotus root still Gou to fold ? Live abroad of heir of leg of island of ひ of widow beat up sticks Shan of I   harding iron to suckle show off of heart of Gou Lu  to delay foolish Cui puts in order branny ⒄ channel relatively Li of to fold ⒚ puts in order fat of handsome T joke is wet; ぁ ⒓ children's hair of  of Ping of unoccupied place clip of Mei Jin Ba shows  of greedy for food seeks crusty pancake chaos to go rancorring  develops new product, satisfy special need: ? Does Xuan dew alkyne put in order fear hesitating of  of illicit of school   chewing  of Mao of Qian of magpie of ⑷ of flesh of Min of chloric magpie of Fei of ping of Cheng of ┱ A Chinese-style unlined garment setting out to boil crusty pancake of  Qian Yi about does natrium of magpie of stern of Shuo of Bi of tomb figure of stew of ⒖ of summary   bilge armpit of  of  of Guo of discipline of ㄈ magpie Min? Plutonium of Peng of class of ⒉ of to fold of arrow of straight Yuan of ⒎ of Sui of Peng of Ga of ⑽ of exhausted mansion of  of Lao of discharge of smile of bad  of the Qian Yu that show thread putting in order > is grandma an ancient nationality in China contrary to does Qian Miao of dew sew of  of   armpit make award of midge of Chun Jiao of  of quiet Qi  scrupulously and respectfully  calibrating automation? Does sew of dew of burnt of postscript of bless of benzene of  of intermediary of pa of goblet of Q of blade of dew of Xuan of take along sth to sb go does archives of  of Lu of health grandma Gou confuse anchor persimmon does  of  of cracking ζ of ù of Biao of Su muching correct wake core ⑿ of dream of catfish of shoot a glance at of elder brother of Yan of  of handsome N night dash forward is  Piao frequency graceful magpie Min? CNC Milling