SU1397741A1 - Temperature-measuring device - Google Patents

Abstract

The invention relates to temperature measurements. The purpose of the invention is to increase the noise immunity of a device. When the output voltages of the integrators 9 and 18 are equal, the comparator 17 is triggered. By its output signal, the shaper 20 generates a pulse arriving at the logic element AND 22. If the output pulses of the comparator 20 do not match, and the strobe counter 21 occurs, the strobe counter 21 and the counter 23 drop. the coincidence of the pulse from the inverted output of the logic element AND 22. The pulse period at the output of the gate counter 21 is equal to the sawtooth period at the integrator output 9. the forming (TA) 1 varies varies the interval between the beginning of the second cycle and strobiroganiem comparator 17. Upon reaching the phase transition points in the reference calibrator material working temperature TA 1 spa long time remains constant. The phase of the pulses at the output of the comparator 17 relative to the second clock cycle does not change in several cycles of the transform -; - NIN. This leads to the coincidence of the pulses in the course of the element AND 22, the counter 23 of the coincidence is filled and a correction signal is generated, which is fed to the input of the control unit 6. 1 il. with

Description

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The invention relates to the field of temperature measurements, k can be used to build temperature measurement tools of high accuracy, in which automatic calibration of the measuring channel is carried out in conjunction with a thermoelectric converter.

The purpose of the invention increase the noise immunity of the device "

The drawing shows a block diagram of the proposed device.

The device contains a thermoelectric converter (TP) 1 with integrated calibrator, adder 2 correction unit 3, switch 4, standard signal source 5, first control unit 6, amplifier. 7, first switch 8, first integrator 9 with analog offset zero offset, reference source 10, first comparator llj second block 12. control, clock pulse generator 13, second switch 14, counter 15, indicator 16, second comparator 17J second integrator 18 with analog by the mix-up zero correction, the third switch 19, the driver 20, the gate counter 21, the AND 22 gate and the match 23 counter.

The device works as follows.

In Calibration mode, the operator switches the object to constant heating or cooling mode. At the operator's command, the first control unit 6, by sending a control signal to the control unit 12, switches it to work in the Calibration mode, prohibiting the signal to be connected to the input of the integrator 9 of the voltage of the source 10 of the reference voltage.

In the first cycle, on command from the control unit 12 supplied to the switches 8 and 19, the amplified signal of the TP 15 is connected to the first input of the integrator 9, as a result of which a signal j proportional to the temperature of the measured medium is formed at its output and the first input of the integrator 18 is connected to zero bus. In the second clock cycle, no signal is applied to the inputs of the first integrator, with the result that its output voltage remains constant, and the voltage to the first input of the second integrator

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from the output of source 10 of the reference voltage.

At the moment of equality of the output voltages of the integrators 9 and 18, the second comparator 17 is triggered. According to its output signal, the shaper 20 generates a 1-pulse fed to the logical element 22, If the output pulses of the comparator 20 and the counter 21 of the gates mismatch, the counters of the gates 21 and the coincidence 23 are reset by the pulse from the inverse output of the logic element I 22. The counter width of the 21 strobe is chosen equal to the counter 15, therefore the period of the pulses at the output of the counter 21 is exactly equal to the period of the sawtooth voltage at the output of the HH j-erpaTopa 9, and the frequency drift of the clock generator does not affect the synchronism of these processes.

At the end of the conversion cycle, on command from control unit 12, the first inputs of the integrators are connected to the zero bus of the device, and the second, connected to the zero bus via storage capacitors (not shown), are connected to the outputs of the comparators 11 and 17, respectively, for automatic zero setting.

If the signal of TP 1 changes, the amplitude of the memorized output voltage of the integrator 9 in the second cycle also changes, which leads to a change in the interval between the start of the second cycle and the comparator 17. The pulses from the output of the last 17 and the counter 21 gates arrive at different times at the inputs of the logic element And 22, and the phase of the gala. The counting in the counter 21 gates after its reset changes. When the phase transition point of the calibrator reference material is reached, the temperature of the working spa TP for a long time (ten seconds) remains constant. In this case, the phase of the pulses at the output of the comparator 17 relative to the start of the second clock cycle does not change for several cycles of conversion. This leads to the coincidence of the pulse E at the input of the logical element I 22 "The successive coincidence of the pulses from the outputs of the comparator 17 and the counter 21 gates during a series of cycles results in filling the counter 23 matches and forming

signal Formation of the amendments to the input unit 6 controls

The control unit 6 switches on the correction unit 3 and transfers the control unit 12 to an operation mode, in which the second voltage source 10 is connected to the input of the integrator 9 and the elements 7-16 start operating in a two-cycle integration voltmeter.

Under the action of the control unit of the control unit 6, the switch 4 opposite the signal of the TP includes the voltage of the source 5 of the standard signal corresponding to the temperature of the phase transition of the reference material of the calibrator. Under the influence of the output signal of the amplifier 7, the output voltage of the correction unit 3 begins to change until the sum of the thermal emf TP and the output voltage of the correction unit 3 becomes equal to the standard signal of the source 5, as evidenced by the absence of voltage at the output of the amplifier 7

This is the end of the Calibration process.

In the Measurement mode, the output signal of the correction unit 3 is continuously added to the TP 1 signal, which results in the correction of the TP error, the communication line, the compensation circuit of the free ends of the TP (not shown), and the analog part of the device.

The phase transition identification circuit of the calibrator reference material (counters 21 and 23, And 22 element, integrator 18, shaper 20, comparator 17) in the Measurement mode is turned off,

The corrected signal from the output of the switch 4 is fed to the input of the amplifier 7 and using the elements 8-16, operating in the digital voltmeter mode of the push-pull integration, is converted into a digital temperature value.

Claims (1)

The device can be implemented on the basis of serial units and elements. The control unit 12 can be executed in the form of a temporary pulse distributor controlled by signals from the counter 15. Invention A temperature measuring device containing a thermoelectric converter with built-in calibra 0 five On the other hand, connected to the first input of the adder, the second input of which is connected to the output of the correction unit, and the output connected to the first input of the switch, the second input of which is connected to the output of the standard signal source, the control input connected to the first output of the first control unit, and the output through the amplifier is connected to the input of the correction unit and the first input of the first switch, the second, third and fourth inputs are connected respectively to the output of the reference voltage source, the output of the first comparator and the zero bus device The control input is connected to the first output of the second control unit, and the input codes are connected to the inputs of the first integrator, the output of which through the first comparator is connected to the first control input of the second switch, the input of which is connected to the generator output of takt5 pulses, the second control input is connected to the second output of the second control unit, and the output is connected to the input of the pulse counter, the output of which is connected to the indicator, and the control input is connected to the third output pervm input of the second control unit, the second input of which is connected to the second output  the first control unit, a third; the output of which is connected to the control input of the correction unit, and the input is connected to the output of the coincidence counter, the counting input of which is connected to the non-inverting output of the logic element I, the first input of which is connected to the output of the gate counter, the input. 5 reset is connected to the reset input of the coincidence counter and connected to the inverting output of the logic element AND, characterized in that, in order to increase the noise immunity of the bone, a second 1- is entered into it: the integrator, the second comparator, the driver and the third switch, control. The input input of which is connected to the auxiliary output of the second control unit, the second, third and fourth inputs are connected respectively to the output of the reference voltage source, the output of the second comparator and the device bus, and the outputs are connected to the inputs of the second integrator, with j o and the second integrator, and the output of the second comparator is connected via a driver to the inputs of the second comparator with the outputs of the first input of the logic element I.