SU1247680A1 - Time-to-pulse converter or device for measuring temperature - Google Patents

Abstract

The invention relates to the field of temperature changes and allows to increase the accuracy of transformation. The device contains a constant voltage source 1, thermal converter 2, capacitor 3, divisors of resistance 4- and 5, comparison circuit 6, pulse generator 7, j keys 8 and 9, transistors 11 and 12, trigger 13 with a counting input and calibration resistance 10. The introduction of new elements and the formation of new connections between the elements of the device allows to take into account the effect on the conversion result of a change in the parameters of the converter elements during I further processing of signals from the output of the comparison circuit 6. 2 Il. to 4 ;; hours 00

Description

I

The invention relates to the field of temperature measurements, namely to temperature transducers in a time interval, working in a set with resistance thermal converters, and can be used in digital temperature gauges.

The aim of the invention is to improve the accuracy of the transformation by taking into account the effect on the result of the transformation of the change in the parameters of the elements of the converter.

Fig. 1 shows a time-pulse converter circuit; in fig. 2 - diagrams explaining his work.

The time pulse converter contains a constant voltage source 1, a thermal converter 2 resistance, a capacitor 3, a resistive divider on resistances 4 and 5, a comparison circuit 6, a pulse generator 7, keys 8 and 9, made, for example, on field-effect transistors, calibration resistance 10, first and second bipolar transistors 11 and 12 and trigger 13 with a counting input.

FIG. Figure 2 shows how the voltage changes at the first and second outputs of the pulse generator (a, b), at the trigger outputs (c, d), at the capacitance when the calibration resistance and the thermal converter are connected (e), at the output of the comparison circuit (e) .

The time pulse converter works as follows.

From the second output of the generator 7, a pulse signal is fed to the input of the trigger 13. When the first pulse arrives at the output of the trigger trigger 13, a positive voltage appears, opening the transistor 12, current flowing through calibration resistance 10, charging capacity 3 starts, speed which depends on the magnitude of the calibration resistance 10 and capacitance 3. At the same time, the negative voltage drop taken from the first output of the pulse generator 7 closes the transistor switches 8 and 9 and at the output of the comparison circuit appears Tel'nykh differential stresses. With an increase in the voltage on the capacitor 3., to a value determined by the ratio of resistances 4 and 5,

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the operation of the comparison circuit 6 and a negative voltage drop appears at its output. Thus, at the output of the comparison circuit 6 a pulse is formed, the duration of which must be constant with the stability of the parameters of all the elements of the converter. This pulse is the standard of precision

10 temperature in the time interval. If during the operation of the converter, its change is detected, then the value of this change is introduced by the correction factor as a result obtained by converting the resistance of the thermal converter into a time interval. When the next pulse arrives at the input of the trigger 13, it enters a new state 20. , opens the transistor 11 and

the capacitor 3 is charged through the resistance thermal converter 2, as a result of which the capacitor is charged, and accordingly the time

When it reaches 25, the corresponding triggered response of the comparison circuit 3 will be cooii-BeTCTBOBaTb measured temperature. Thus, a sequence is formed at the output of the comparison circuit.

30 pulses, one of which is calibration and the other measuring. The duration of the calibration pulse is set longer than the measurement duration, the effective 35 6jM corresponding to the minimum

temperature, so they are easily distinguished.

Due to the fact that the same elements are used to form the measurement and calibration signals, destabilizing factors equally affect the characteristics of both signals, which allows to take into account the change in the parameters of the converter elements during further processing of the signals from the output of the comparison circuit.

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The pulse transducer of the temperature meter contains the first bipolar transistor, the collector of which is connected to the first output of the constant voltage source, and the emitter is connected to the per 3 through a resistive temperature transducer.

the output input of the comparison circuit, connected via a parallel-connected capacitor and the first switch to the common bus of the converter connected to the second output of the constant voltage source, a second switch connected between the common converter width and the output of the reference circuit whose second input is connected to the midpoint of the resistive divider voltage connected to a constant voltage source, a pulse generator, the first output of which is connected to the control inputs of keys, characterized in that, in order to increase the accuracy transformations

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by taking into account the effect on the conversion result of the change in the parameters of the converter elements, a second bipolar transistor, 5 calibration resistance and a counting trigger, whose input is connected to the second output of the pulse generator, are entered, and the outputs are respectively connected to the bases of the first and second bipolar transistors, at the same time, the collector of the second bipolar transistor is connected to the first transistor of the constant voltage source, and the emitter is connected to the first input of the circuit with a calibration resistance avneni.

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Claims (2)

SUMMARY OF THE INVENTION A time-pulse converter of a temperature meter containing a first bipolar transistor, the collector of which is connected to the first output of a constant voltage source, and the emitter is connected to a 3 1247680 by the input of the comparison circuit connected through a parallel connected capacitor and the first key to the common 'bus of the converter connected to the second output of the DC 5 voltage source, the second key connected between the common bus of the converter and the output of the comparison circuit, the second input of which is connected to the midpoint a resistive voltage divider 10 connected to a constant voltage source, a pulse generator, the first output of which is connected to the control inputs of the keys, characterized in that, with the aim of 15 increase conversion accuracy by taking into account the influence on the conversion result of changing the parameters of the converter elements, a second bipolar transistor, a calibration resistance and a counting trigger are inserted into it, the input of which is connected to the second output of the pulse generator, and the outputs are respectively connected to the bases of the first and second bipolar transistors, while the collector the second bipolar transistor is connected to the first output of the constant voltage source, and the emitter is connected to the first through a calibration resistance Valid comparisons schemes. FIG. 1