Ntawm cov qauv tsim thiab kev thov ntawm thermocouple sensor kub ntsuas ntsuas

Raws li ib qho ntsuas kub ntsuas, lub thermocouple sensor tau tau siv dav .
Cov hauv qab no yog qhov ntsuas kub uas ntsuas tau los ntawm ib nti microcomputer, uas muaj peb ntu: (1) Circuitar Circuities; (2) A / D hloov dua txoj kev tsheb kauj ruam; (3) teeb tsa Circuit Court. nws yog dav siv hauv cov ntsuas kub thiab cov nroj tsuag kub thiab cov nroj tsuag {4}
1.} kho vajtse tsim
(1) thermocouple kub sensor
Cov kab ke no siv Nickel-chromium-lickel-silicon thermocouped los ntawm cov kev hloov pauv ntawm thermoelectric muaj peev xwm los ntawm kev hloov pauv ntawm qhov txias txias ntawm lub Thermocouple {{}} Txoj cai tswj hwm ciam av muaj plaub ntawm Thermocouple wring thiab lub cav txias R 1= r} r}} r} REt}} REt}}}}} Tus choj yog feem ntau sib npaug ntawm 20℃. Nyob rau lub sijhawm no, plaub tus choj tawm tsam ntawm 20} rcu} rcu, rcu} rcu, thaum nws nce ntxiv, thaum lub peev xwm kub hnyiab tau ntawm thermocouple txo qis dua li qhov kub txias txias ntxiv {29} Uab Up yog sib npaug ntawm kev ua tiav kev ua tiav ntawm kev ua tiav txias kawg ntawm kev mob khaub thuas kawg
(2) ntsuas ntsuas hluav taws xob
Hauv kev voj voog tiag tiag, cov teeb liab tawm los ntawm thermocouple tsis muaj ntau tshaj li ob peb kaum ntawm cov zeb (<30mV), and contains common-mode interference such as power frequency, static electricity and magnetic coupling. To amplify this kind of circuit, the amplifier circuit needs to have a high common-mode rejection ratio, high gain, low noise and high input impedance. Therefore, a measurement amplifier circuit is suitable. The measurement amplifier is also called a data amplifier, instrument amplifier and bridge amplifier. It has a high input impedance and is easy to match with various signal sources. Its input offset voltage, input offset current and input bias current are small, and the temperature drift is small. Due to the small time temperature drift, the measurement amplifier has good stability. The measurement amplifier is composed of three op amps, and the differential input terminals R1 and R2 are connected to the in-phase terminals of A1 and A2 respectively. The input impedance is very high, a symmetrical circuit structure is used, and the measured signal is directly added to the input terminal, thereby ensuring a strong ability to suppress common-mode signals. A3 is actually a differential follower, and its gain is approximately 1. The gain of the measuring amplifier is: AV=V0/(V2-V1), AV=Rf/R(1+(Rf1+Rf2)/RW). In this circuit, as long as the performance of op amps A1 and A2 is symmetrical (mainly referring to input impedance and voltage gain), their drift will be greatly reduced. They have high input impedance and common mode rejection ratio, are very sensitive to tiny differential mode voltage, and are suitable for measuring signals transmitted over long distances. Therefore, they are very easy to use with sensors with tiny outputs. RW is an external resistor used to adjust the gain, and a multi-turn potentiometer is used here.
Nyob rau hauv qhov tseeb Circuit Court, A2 siv qis-drift, high-precision op {}}}}}}}}}}}}}}}}}}}}}} dav siv nyob rau hauv kev sib koom ua ke ruaj khov, kev sib ntxiv tau thiab kev hloov kho kub}}} A3 siv 741 chip, uas yuav tsum tau siv dua qub yog} 15}}
(3) A / d (analog-rau-digital) hloov dua tshiab
Lub ntsuas hluav taws xob hluav taws xob tawm los ntawm kev ntsuas ntsuas tau muaj qhov ntsuas hluav taws xob, yog li A ICL7109 yog lub siab-precision, qis-suab nrov, Tsawg-drift, tus nqi qis dual-{11}} me ntsis12-}}}}}}}}}}}}} Koj tuaj yeem siv sijhawm nrawm ntsuas kev ntsuas rau ntau lub cim sensor xws li hnyav, ntsuas kev ntsuas siab, thiab ntsuas kub {18 {}
Los ntawm kev txheeb xyuas saum toj no ntawm Thermocouple sensor kub ntsuas ntsuas kev ntsuas, Kuv vam tias nws yuav pab tau txhua tus neeg ua haujlwm thiab kawm .