20.500.12556/RUL-141458 Preverjanje možnosti uporabe senzorskega elementa P14 2FW Thermo v merilniku točke rosišča s samokalibracijo Possibility of using the P14 2FW Thermo sensor element in a dew point meter with auto-calibration V magistrskem delu se soočimo s problemom izdelave točnega in dolgoročno stabilnega merilnika točke rosišča v sistemu komprimiranega zraka. Predstavimo načrtovanje in izdelavo dveh pilotnih prototipov merilnika točke rosišča z analognim senzorskim elementom P14 2FW Thermo, ki je edini na trgu dostopen element, s katerim bi bilo morebiti možno izdelati merilnik točke rosišča. Sestavljata ga kapacitivni senzor relativne vlage in uporovni (Pt-100) senzor temperature. Primarni prototip je bil namenjen testiranju senzorskega elementa in opazovanju njegovega odziva na spreminjanje relativne vlažnosti zraka. Rezultati testiranj so pokazali, da ima senzorski element dober odzivni čas na spremembo vlage, a slabo ponovljivost. Rezultati so nakazovali tudi potrebo po pogosti kalibraciji merilnika zaradi lezenja meritev. Zaradi občutljivosti merilnega sistema, ki smo ga uporabljali za opazovanje delovanja primarnega prototipa merilnika, smo zgradili novo, robustnejše testno okolje za izvajanje meritev. Izdelali smo sekundarni prototip, pri katerem smo s primernejšo zgradbo merilnika odpravili šum, ki je bil prisoten na meritvah s primarnim prototipom. S pomočjo izvajanja protokola samokalibracije, ki ga je leta 1991 patentiral večji proizvajalec podobnih merilnikov, smo poskušali doseči stabilnejše meritve. Med izvedbo izbranega protokola je senzorski element za kratek čas segret do visoke temperature (okrog 150 °C), pri čemer se popolnoma osuši. Na tak način definiramo kapacitivnost senzorja relativne vlage v popolnoma suhem zraku. Izkazalo se je, da ta rešitev za izvedbo merilnika s senzorskim elementom P14 2FW Thermo ni izvedljiva, saj je izbrani senzorski element termično preobčutljiv. In this master’s thesis, we are faced with the problem of making an accurate and long-term stable dew point meter in a compressed air system. We present the design and production of two pilot dew point meter prototypes using an analog sensor element P14 2FW Thermo. It is currently the only element available on the market suitable for making such a meter. The element consists of a capacitive relative humidity sensor and a resistive (Pt-100) temperature sensor. The first prototype was intended to test the sensor element and observe its response to changing humidity. The results showed that the sensor element has a good response time to humidity changes, but poor repeatability. Consequently, the need for frequent calibration of the meter due to measurement creep emerged. Since the initial measurement system used to observe the performance of the first prototype was too sensitive, we built a new, more robust test environment to perform measurements. In the second prototype, the noise that was observed in the measurements of the first prototype was eliminated by more suitable structure of the meter. Further, by implementing an auto-calibration protocol that was patented in 1991 by a major manufacturer of similar devices, we tried to eliminate the creep. The selected protocol requires the sensor element to be heated to a high temperature (around 150 °C) for a short period of time during which it dries completely. Thus, the capacitance of the relative humidity sensor in a completely dry air can be defined. It turned out that such an implementation of the meter is not feasible with the selected sensor element since the sensor is not robust enough. točka rosišča relativna vlažnost merjenje kapacitivnosti referenčna vlažnost solne raztopine samokalibracija dew point relative humidity capacitance measurement salt solution humidity reference auto-calibration true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2022-09-29 13:55:00 2022-09-29 13:55:04 2022-10-06 14:30:38 0000-00-00 00:00:00 2022 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 61044 124556291 Simoncic_Izidor_-_Preverjanje_moznosti_uporabe_senzorskega_elementa_P14_2FW_Thermo_v_merilniku_t.pdf Simoncic_Izidor_-_Preverjanje_moznosti_uporabe_senzorskega_elementa_P14_2FW_Thermo_v_merilniku_t.pdf 1 3392D711DE63188D5E449EB2E63B241F 52e4ae0ee62a7be802d389be8a0d54eac15f903b6f19616a17131652c93bd1fb 8fbdba0e-3fed-11ed-9c94-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=162528 Fakulteta za elektrotehniko 0 0 0