SU930022A1 - Device for remote measurement of temperature - Google Patents

Description

(54) DEVICE FOR REMOTE MEASUREMENT

I

The invention relates to thermometry, specifically to devices for. remote temperature measurement.

A device for remote temperature measurement is known, which contains a thermoresistive element connected to an electrical resistance-to-electrical converter, the output of which is connected to the recorder tl3 via a communication line.

The drawback of the device is the low measurement accuracy due to the non-linearity of the function. The conversion of the device and the instability of the parameters of the conversion function, depending on external conditions and in time.

The closest in technical essence to the present invention is a device for remote temperature measurement, comprising a thermal sensor made in the form of two reference resistors connected in series and two identical thermistors, one of which is connected in parallel. TEMPERATURES

the third thermistor is identical to the first two, where the terminals of the modulator resistors are connected via the control switches of the switch to the input of the converter electrical resistance to an electrical signal, and the output of the converter is connected to the calculator-recorder via a communication line.

To eliminate the effect on the result. Measuring the nonlinearity and instability of the conversion function of the measuring circuit The temperature measurement is carried out in. four stages with the subsequent processing of the results according to the defined algorithm 2.

The drawback of the device is the effect on the measurement results of the residual resistances of the switch keys.

The purpose of the invention is to improve the measurement accuracy.

Claims (2)

This goal is achieved by the fact that in a device containing a thermal sensor made in the form of serially connected two reference resistors and 393 two identical thermistors, one of which is connected to the third same thermistor, a converter of electrical resistance of the thermal sensor into an electrical signal, which through four controlled the switch key is connected to the three middle and one extreme terminals of the temperature sensor resistors, and the communication line connected to the transmitter-recorder, the transducer The electrical resistance device is located in the Lenin thermal sensor as a stabilized DC source, and the extreme leads of the thermal sensor are connected to a line through the additionally introduced voltage meter (; in). The device for remote temperature measurement contains a thermal sensor 1 that includes two reference resistances R fl-1 identical thermistor R., R and R {;,. The extreme terminals 2 and 3 of the thermal sensor are connected to the input of the voltage meter 4. The output of the voltage meter 4 is connected via a link 5 to the calculator-recorder 6. The extreme terminal 2 and the middle terminals 7-9 of the thermal sensor resistors. Through controlled keys 1 - 13 connected to the input of a stabilized current source 14. The control unit 15 for busbars 16-19 of the control is connected with the control inputs of the keys 1O - 13. Since the internal resistance of the current source I) 1fits: much higher than the load resistance, then when switching the thermal sensor outputs, the residual resistance of the keys does not affect the amount of current flowing through temperature resistors. The device works as follows. In the first measurement step, the control unit 15 outputs a control signal via the bus 17, which decouples the key 11. In this case, the keys 10-13 remain closed. Through the resistance of the open transition, the input-output of the controlled switch II and through the series-connected in l / in parallel with which Rt the current of the stabilized source flows, since the Rgy voltage meter is constant, the current is selected so that ... - ...., 01% where H is the value of the resistance of the thermal device / sensor when switched on, respectively, of controlled keys 10–13. Considering that the amount of current through the resistors of the thermal sensor does not depend on the residual resistance of one of the open controlled keys 1О-13, the electrical signal at the output of the calculator is v1MXK4) -. where Co K at and where i, VHa is the initial value of the output -1 signal with private keys g 10 - 1 G G JE - is the sensitivity of the meter 4 voltage; g - is the nonlinearity coefficient of the voltage detector 4 voltage. In the second measurement step, the control unit 15 opens the control key 12 and closes the key 11. An electric signal appears at the input of the sweeper: v% r-uv H. aS In the third measurement step, the control unit 15 opens the key 13 and closes the key 12. On The output of the calculator is N, 4 (("0- -", t. In the fourth measurement step, the control unit 15 opens the key 10 and closes the key 13. At the same time, an electrical signal appears at the output of the calculator ... .. Results M, - N The measurements are processed in the calculator 6 by al-light vs Kiv4K. VN K V4K4J-M lV))% T. H (). Thus, when processing the results of the four measurement steps according to the indicated algorithm, we have the #-) aet. - Taking into account that the resistance R .. is related to the temperature measured by f. () where R 4-rt is the resistance of the thermometer at t ° OPCj d is the temperature-to-electrical resistance coefficient of the thermometer, for the measured temperature we obtain N, -N PTW.-M -. The invention makes it possible to increase the accuracy of remote temperature measurement, which is determined essentially by the accuracy class of the thermoresistant element itself and does not depend on the parameter of the switch, the measuring circuit and the communication line. Apparatus of the Invention A device for remote temperature measurement, comprising a thermal sensor, made in the form of series-connected two reference resistors and two identical thermistors, parallel to one of which is connected the third same thermistor, a sensor of electrical resistance of the thermal sensor into an electrical signal, which through four control switches of the switch connected to three mediums shm and to one extreme point of resistor temperature sensors, and a communication line connected to the computer-p recorder of, characterized in that, with -; The aim is to improve measurement accuracy by eliminating the effect of residual co. key resistance, an electrical converter, the resistance of the thermal sensor is made in the form of a stabilized DC source, and the extreme terminals of the thermal sensor are connected to the communication line through an additionally introduced voltage meter. Sources of information taken into account in the examination 1. Novitsky OP. V. and others. Digital devices with frequency sensors. M., Energie, 1970, p. 91-102. 2. Copyrights certificate CfCCP NO 581в89, cl. C5 01 K 7/16, 1974. Z-}