SU1525476A1 - Digital meter of rate of temperature change - Google Patents

Abstract

The invention relates to temperature measurements and makes it possible to increase the accuracy of measuring the rate of change in temperature by increasing the ratio of useful signal to noise. A frequency signal is supplied to the input of the switch 7 from the output of the voltage-frequency converter 17, the value of which is proportional to the temperature of the resistance thermal converter 1. A reversible counter 9, controlled by signals from the output of the first frequency divider 8, determines the rate of temperature change, which is displayed on the digital indicator 11. If the magnitude of the temperature change is small, the elements AND 13.15, AND-NOT 12 and HE 14 generate signals into counter 16, which with the help of decoder 6, switch 5 changes the dividers of 10.8, increasing the time between two temperature readings. The clock generator 3, the driver of the 4 time intervals, the driver 19 of the control pulses provide the formation of the necessary control signals to the control inputs of the switch 5 and the device 18 sample-store. 1 il.

Description

(L

resistance A reversible counter 9, controlled by signals from the output of the first frequency divider 8, determines the rate of temperature change, which is displayed on the digital indicator 11. If the amount of temperature change is small, the elements AND 13, 15, AND-NOT 12 and HE 14 form signals into counter 16, which with the help of decoder 6, switch 5 changes the coefficients

5254764

nor dividers 10, 8, increasing the time between two temperature readings. 3 clock pulse generator,

The shaper 4 time slots, shaper 19 control pulses provide the formation of the necessary control signals to the control inputs of the commutator 5 and the sampling-storage device 18. 1 il.

The invention relates to temperature measurements, namely, devices for measuring the rate of temperature change, and can be used in automated heating control systems, as well as in automatic systems for calculating the temperature profile of heated bodies.

The purpose of the invention is to increase the measurement accuracy by increasing the wanted signal-to-noise ratio.

The drawing shows a block diagram of a digital meter for the rate of change of temperature.

Digital temperature rate meter contains thermal converter 1, amplifier 2, 3 clock pulse generator, shaper 4 time slots, first switch 5, decoder 6, second switch 7, first frequency divider 8, reversible counter 9, second frequency divider 10, digital indicator 11 , the logical element AND-NOT 12, the first logical element And 13, the logical element NOT 14, the second logical element And 15, the counter 16, the voltage-frequency converter 17, the device 18, the sample-storage and the driver 19 control pulses.

The meter works as follows.

The signal from thermal converter 1 is amplified by amplifier 2 and fed to sampling-storage device 18. The latter, in the sampling mode, stores the instantaneous value of the signal, and then, at the command of the output of the imaging unit 19, the control pulses go into storage mode. It serves to eliminate the dynamic error in temperature measurement, which

35

This may occur due to a discrepancy between the recorded points in time and the measured instantaneous temperature values, since each instantaneous temperature value is converted into a digital code not instantly, but over a certain period of time during which the temperature changes . From the sampling-storage device 18, a fixed (memorized) instantaneous value of the signal is fed to the converter 17, the voltage -, Q is the frequency, which generates pulses with a frequency f proportional to the measured temperature. The pulses from the output of the converter 1 7 voltage - the frequency is fed to the switch 7, controlled by the decoder 6. From the output of KObiMyTaTO 7 the signal of the voltage converter 17 - the frequency goes to the corresponding input of the divider 10, which divides the 0 pulse frequency into the appropriate number of times (1,2,3, ..., p), depending on the required measurement accuracy.

From the output of the divider 10, the pulses are fed to the counting input of the reversible counter 9, which counts the number if there are control signals at the inputs 20 and 21, the frequency of which also depends on the magnitude of the temperature change. The control pulses are generated by the shaper of 4 time intervals from the clock pulses received from the generator 3 clock pulses. From the first and second outputs of the former 4 time intervals, pulses with a duration of sic are applied to the input of the switch 5 to control the reversible counter 9. The period of the track 50

55

vani 2T

of these pulses t and t, r. jlj equals

, accordingly. From the third output of the imaging unit 4 to the commutator 5, 1 / f pulses are sent to reset the reversible counter 9, their tracking period is T. These pulses also enter the input of the imaging unit 19 control pulses, generating a signal to control the operation of the UHP 18. Moreover, the pulses The first and second outputs of the imaging unit 4 appear synchronously and are lagging in time by l / f from the pulses at the third output. From the output, the switch 5, controlled by the decoder 6, receives pulses at the corresponding inputs of the second frequency divider 8, in which, depending on the temperature change, each of the pulse sequences, the postformer 4, is divided by the appropriate number of times (1, 2, 3, ...,P).

When pulses appear simultaneously at the control inputs 20 and 2 of the reversing counter 9, the counter performs summation over I from the pulses arriving at its counting input from the divider 10. Then, after an interval T at the control input

20 of the reversing counter 9, a pulse appears, and at the control input

21 is a zero signal, and the reversible counter 9 produces the subtraction of pulses arriving within 1 s at the counting input. If the value of the temperature change over the interval T is higher than the sensitivity threshold of this device, the number 9 proportional to the rate of temperature change is fixed in the reversible counter 9, and the digital indicator I highlights this number and the derivative sign on its scoreboard. The information in the reversible counter 9 is reset by a signal arriving at control input 22. If the magnitude of the temperature change during the interval T is lower than the sensitivity threshold of the device, the device automatically selects the desired interval T for which the magnitude of the temperature change will become clear. This happens as follows. The output of each bit of the reversing of the 1st counter 9 is connected with the input of the input NAND 12 and, 5

ten

20

525476

if and the reverse counter 9 recorded a zero number, then triggered ale. the cop is AND-NOT 12, and at its output a signal appears in the form 1, which enters the input of the element AND 13. Then, when a second pulse appears at the second input of the element 13, the third output of the former 4 at the output of the element 13 appears whose duration is equal to the duration and - {pulse, received at the second input of this element. This pulse arrives at the counting input of the counter 16, which controls the operation of the decoder 6, and the decoder provides simultaneous connection of the output of the converter 17 and the former 4 via switches 7 and 5 to the inputs of dividers 10 and 8, ensuring a 2-fold division of the frequency of the incoming pulses. If the interval T again turns out to be insufficient to measure the magnitude of the temperature change, then the frequency of the pulses from the converter 17 and the former 4 Judges decrease by 3, 4, ,,..., As long as the reversible counter 9 records a measurement result that differs from zero . Then, at the output of the AND-NOT 2 element, the coolant level goes to the input of the HE 14 element, and the output of this circuit is a signal that enters one of the inputs of the 15th element. When the next pulse appears from the third output, the 4th element I I5 sends out a reset pulse to counter 16, and the device is ready for the next measurement. If the value of the temperature change is less than the sensitivity threshold and at the interval T, O is on the digital indicator, and the signal from the last full discharge of counter 6 will reset it and odgotovit for the next measurement.

25

thirty

35

40

45

Claims (1)

Invention Formula A digital temperature rate meter containing a thermocouple connected to the amplifier input, a time interval shaper whose input is connected to the output of the clock generator, and the first, second and third outputs are connected to the corresponding inputs of the first switch, a decoder whose outputs are soy / t .ineny with entrances the first and second switches, the first frequency divider, the inputs of which are connected to the outputs of the first switch, the reversible counter, whose outputs are connected to the indicator, the first, second and third control inputs are connected to the corresponding outputs of the first frequency divider, and the counting input is connected to the output the second frequency divider, which is connected to the outputs of the second switch, characterized in that, in order to improve the measurement accuracy, a sampling-storage device is inserted into it, the voltage converter is stack, driver of control pulses, counter, first and second logical elements the cops AND, the logical element NOT and the logical element NAND, whose inputs are connected to the outputs of the reversible counter, and the output connected to Q five 0 the first input of the first logical element AND and the logical element is NOT connected to the first input of the second element AND, the second input of which is connected to the first input of the first logical element AND and the third output of the time interval generator, and the code is connected to the control input of the counter connected to its output the higher bit, the counter input of the counter is connected to the output of the first logic element AND, and the outputs are connected to the inputs of the decoder, while the input of the sampling-storage device is connected to the output of the amplifier, The developing input is connected via the driver control pulses to the first output of the time slots, and the output voltage through the inverter frequency is connected to the input of the second switch.