Wadanda Tsaki na Tashar Jiki ko RTD | Kudin Yadda Ake Gargajiya da Koyar Shiga
Me ke RTD (Resistance Temperature Detector)?
RTD (Gwadon Tsakiyar Jiki) ko karamin alama da ake amfani da ita don taka tsakiya ta jiki daga masu jirgin ruwa. Wannan jirgin ruwa shi ne ce ake fara a matsayin gwadon tsakiya. Idan muna so in taka tsakiya da kyau, RTD shi ne ce zan iya ba muka.
Wadannan babban nasararsa ga wadannan abubuwan da ake amfani da su don taka tsakiya sun hada da thermocouple da kuma thermistor.
Karin jirgin ruwa da ke faruwa a kan karfin jiki ya kasance,
Inda Rt da R0 sun hada da ma'aikatar jirgin ruwa a tafkin jiki toC da t0oC. α da β sun hada da ma'aikatar mutanen hanyoyin.
Wannan bayanin ya kasance saboda ingancin tafki. Don tafkin yawan da yawa, wannan bayanin ya kasance,
A cikin abubuwan da ake amfani da su a cikin RTD, Copper, Nickel da Platinum sun fi sani. Wadannan uku suna da inganci mai faruwa a kan karfin jiki. Wannan suna nufin ma'aikatar jirgin ruwa da karfin jiki.
Platinum tana da inganci a kan karfin jiki da 650oC, Copper da Nickel suna da 120oC da 300oC. Figurin-1 tana nuna kurba na ma'aikatar jirgin ruwa da karfin jiki wadannan uku. Platinum tana faruwa a kan jirgin ruwa da 0.4 ohms a baya har zuwa toC.
Zan iya duba kyakkyawar Platinum tare da R100 / R0. Saboda idan wannan alama ba da kyakkyawa, za a faruwa a kan bayanin ma'aikatar jirgin ruwa da karfin jiki. Saboda haka, ma'aikatar α da β suna faruwa saboda hanyoyin.
Babban Nasarar RTD
Babban nasarar RTD tana da wannan nasarar da ake faruwa a kan form (a cikin coil) a kan mica cross frame don samun girman tasiri, kuma a yi aiki da wanda yake da damar jiki da ake faruwa a kan tafki. A cikin RTD na mulkin, an gaba a coil da shekara da stainless steel sheath ko a protective tube.
Saboda haka, abin da ake faruwa a kan jirgin ruwa tana da damar jiki da ake faruwa a kan tafki. Idan ake faruwa a kan jirgin ruwa, za a faruwa a kan jirgin ruwa. Saboda haka, ba muna so in a faruwa a kan jirgin ruwa saboda abubuwan da ba su da kyau. Wannan tana taimaka a cikin ci gaba da RTD a lokacin da ake yi aiki. Mica tana da damar jiki da ake faruwa a kan shekara da resistance wire.
Signal Conditioning of RTD
A maida aiki da RTD, muna son in ka duba tarihin tattaunawa da kuma a yi aiki da signal conditioning circuitry. Saboda haka, ake faruwar jirgin ruwa da abubuwan da ba su da kyau. A cikin RTD, karin jirgin ruwa da ke faruwa a kan tafki tana da yawa.
Saboda haka, RTD tana daidaita da bridge circuit. Tana da electric current da ake faruwa a kan bridge circuit, kuma ake faruwa a kan voltage drop across the resistor, RTD resistance tana daidaita. Saboda haka, tana daidaita a cikin tafki. Tafki tana daidaita tare da a yi aiki da calibration expression. Wadannan modules na RTD suna nuna a cikin figur.
A cikin two wires RTD Bridge, dummy wire ba a nan. Ake faruwa a kan labaran da ake faruwa a kan fig.3. Amma ake faruwar jirgin ruwa da ke faruwa a kan extension wires tana da muhimmanci, saboda impedance na extension wires zai iya faruwa a kan tafki. Wannan tana daidaita a cikin three wires RTD bridge circuit tare da a faruwa a kan dummy wire C.
Idan wires A da B suna da damar length da cross section area, za a faruwa a kan impedancen da suka faruwa saboda ake faruwa a kan opposite position. Saboda haka, dummy wire C tana da damar jiki da ake faruwa a kan voltage drop across the RTD resistance da kuma ba ake faruwa a kan current. A cikin waɗannan circuits, output voltage tana daidaita tare da tafki. Saboda haka, muna son in a faruwa a kan calibration equation don taka tafki.
Expressions for a Three Wires RTD Circuit
Idan muna son in ka duba VS da VO, muna son in ka duba Rg da kuma tafki tare da a yi aiki da calibration equation. Za a faruwa a kan R1 = R2:
Idan R3 = Rg; then VO = 0 and the bridge is balanced. This can be done manually, but if we don’t want to do a manual calculation, we can just solve the equation 3 to get the expression for Rg.
This expression assumes, when the lead resistance RL = 0. Suppose, if RL is present in a situation, then the expression of Rg becomes,
So, there is an error in the RTD resistance value because of the RL resistance. That is why we need to compensated the RL resistance as we discussed already by connecting one dummy line ‘C’ as shown in fig.4.
Video Presentation on Resistance Temperature Detector or RTD
