Termojuft sensori haroratini o'lchash tizimini loyihalash va qo'llash bo'yicha

Oddiy haroratni o'lchash elementi sifatida termojuft sensori keng qo'llanilgan . .
Quyida uchta chip mikrokompyuteridan boshqariladigan oddiy harorat o'lchash tizimi uchta qismdan iborat: (1) o'lchash kuchaytirgichini o'lchash; (2) A / D konversiyalash tovyurti; (3) {{3} tozalash vositalarini ko'rsatish . elektr stantsiyalar va kimyoviy o'simliklardagi haroratni o'lchash va haroratni boshqarish tizimlarida keng qo'llaniladi .
1. Uskuna dizayni
(1) Termojle harorati sensori
Ushbu tizim Nikel-xrom-n nikel-kremniy termoxolatidan foydalanadi . . darajasi . - bu sovuq oxirigacha o'zgarishi mumkin bo'lgan kompensatsiya ko'prikning kompensatsiyalash usuli. Termosple . Blignomasmasrik Condits .} R3, R3, R3, R3, R3 (Morganose mis sim simlari) va termojuftning sovuq uchidan iborat. {0 Assistent va R 2= R 2= 2= 3=1 3=1 . .} RSOM - bu hozirgi cheklangan rezistor va uning chidamliligi qiymati boshqacha. thermocouples. The bridge is usually balanced at 20℃. At this time, the four bridge arm resistances of the bridge are R1=R2=R3=Rcu, and there is no output at ends a and b. When the cold end temperature deviates from 20℃, for Misol, ko'tarilganda, RCU oshadi, therozouelning issiqlik potentsiali issiqlik potentsialining pasayishi va uab issiqlik displektsiyasining oshishi bilan o'zgarib turadi, shu bilan sovuq tugaydi .
(2) o'lchash kuchaytirgich
Haqiqiy slanquvlarda termojuftdan signal chiqishi bir necha o'nlab mlrdolts (<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.
A1 va A2 haqiqiy pog'onada past darajadagi OP -07 haroratni kamaytiradigan va "Zener, Vios" va Iiosni juda oz "deb baholaydilar. Agar kuchsizlantiruvchi signallarni talab qiladi, odatda kuchli signallarni talab qiladi va haroratning o'zgarishi kerak . darajasi . . . . . . . Agar nolni sozlash talab qilinmasa, RW dan foydalanish mumkin Ichki quvvat manbai {- ± 5v . ± 5v . ± 5v . ± 5v . ± 5.} ± ± 5.}} dan yuqori yoki unga teng bo'lishi kerak bo'lgan 741 chipni sozlash ¼ 15v. talab qilinadi .
(3) A / D (analog-raqamli) konversiyalash davri
Ushbu signalni haqiqiy pallasida o'lchash signalida . voltajli kuchlanish ko'rsatkichiga ega va kompyuter tomonidan qabul qilinishi mumkin emas. past darajadagi, arzon narxlardagi ikki tomonlama 12- Converter . Converter BUDID BO'YI O / D CENTERNER BUDID BU QURILIShI MUSTAHKAMLANDI. O'lchash, o'lchash bosimi va o'lchash harorati va o'lchash harorati kabi turli xil sensor signallari uchun yuqori aniqlikdagi o'lchash tizimlari .
Termojuft haroratini o'lchash tizimini yuqorida tahlil qilish tizimi, har kimning ishi va o'qish uchun foydali bo'ladi deb umid qilaman .