LIMITS OF THERMOELECTRIC TEMPERATURE DIFFERENCE MEASUREMENT TOOLS WITH AUTOMATIC ADJUSTMENT

2018;
: pp. 39-47
1
Lviv Polytechnic National University
2
Lviv Polytechnic National University
3
Lviv Politecnic National University

The accuracy of temperature difference meters depends on technological parameters of controlled processes. The meters of temperature difference can be constructed for operation in a wider temperature range. Their accuracy is determined by the non-identity of the sensors transformation functions.

Cyber-physical systems as scattered intelligent systems, based on interacting networks of physical and computing components, provide new functionalities for improving the quality of measurement processes. It is proposed to carry out automated operational setup of metrological parameters of digital meters of temperature difference during operation. The secondary device is offered to be implemented on the basis of chip-based programmable structures using coded multi-valued voltage measures. The outputs of both temperature sensors and outputs of the code controlled voltage measure can be connected to different inputs of the measuring device, with their switching and activation being carried out programmatically without additional hardware.

Operative debugging of a digital temperature difference meter is proposed that consists in the alternating installation of each of the thermoelectric transducers in media with known temperature values. At the same time, another source of differential input of the meter is connected to the output voltage of the code-controlled voltage measure fed into a code proportional to the code of the known temperature values. It is proved that in this way it becomes possible to adjust the errors caused by instrumental errors of the temperature sensors of both measuring channels. Changing the codes of control of the voltage measure, we can determine the conversion factor of the secondary device at the given temporal and operating conditions. A detailed analysis of the errors is performed during the execution of the procedures for adjusting the parameters of both measuring channels.

[1] N. Matthias. Elektrische Temperaturmessung, JUMO GmbH & Co. [On-line]. Available:  https://www.jumo.net/ attachments/JUMO/attachmentdownload?id=5116.

 [2] T. Oleskiv, V. Yatsuk, “Metrological support of temperature difference meters on the basis of platinum thermocouples with a two-line communication line”, Measuring equipment and metrology, Lviv Polytech. Nat..Univ., Ukraine, no.74, p.25-28, 2013.

[3] Yu. Strileckyj, G. Vynnychuk, O. Sereduik, “Metrological examination of the device for precision measurement of temperature difference”, Information processing systems, no.2, p.100-103, 2015.

[4] O. Kucherenko, M. Jermolenko, “Influence of the emissivity of the model of an absolutely black body on the measurement of the noise equivalent to the difference in the temperature of the thermal imager, Methods and systems of optical-electronic and digital signal processing, Series Appliance development, NTUU “KPI”, no.47(1), p.72-78, 2014.

[5] V. Latenko, “Method of application of a pair of resistive sensors to measure temperature difference”, Measuring and computing engineering in technological processes. Ukraine, no.4, p. 68-73, 2014.

[6] Ye. Polischuk, M/ Dorozhovets, B. Stadnyk, O. Ivakhiv, T. Bojko, A. Kovalchyk, Means and methods of measuring non-electric quantities, Lviv, Ukraine: Beskyd-Bit, 2008.

[7] Smart Sensor Systems, edited by G. Mejer, John Wiley & Sons, 2008.

[8] V. Osadchuk, O. Osadchuk, N. Kravchuk. Microelectronic temperature sensors with frequency output. Vinnytsa, Ukraine: Universum-Vinnytsa, 2007.

[9] Kh Vasylykha, Yu. Yatsuk, V. Zdeb, V. Yatsuk, “Experimental studies of temperature channel efficiency for solar energy systems”, Eastern-European Journal of Enterprise Technologies, vol.3/8 (87), p.10-16, 2017.

[10] L. Anatychuk. Thermoelements and thermoelectric devices. Kyiv, Ukraine: Naukova dumka, 1979.

[11] F. Lineveg. Temperature measurement in engineering [Russian translation], Moskow, USSR: Metallurgia, 1980.

[12] Yu. Skrypnyk, O. Dubrovyj, P. Chefranov, “Thermoelectric device for measuring temperature difference”, Pat. Ukraine, no.53288A, MPK G01K 7/14, Jan. 15, 2003.

[13] .V. Shevchuk, “Thermocouple signal simulator”, Pat. RF, no.RU2324908C2, June  22, 2006.

[14] R. Matviyiv, V. Yatsuk, “Analysis of frequency characteristics of correction of additive displacements in constant voltage calibrators”, Measuring equipment and metrology, no.8, p.15-18, 2017.