SU1619071A1 - Meter of index of thermal lag of frequency thermal converters - Google Patents

Abstract

The invention relates to the field of heat engineering measurements and makes it possible to increase the measurement accuracy of the thermal inertia indicator by reducing the mean square measurement error. The distributor 6 clocks together with the generator 5 clocks and triggers 7, 8 form two time intervals dc shifted relative to each other by a time interval (0 Ds / 3, during which the pulses from the output of the thermoconverter arrive through the pulse shaper 1 and logical elements AND 2,3, respectively, on the summing and subtracting inputs of the logarithmic reversing counter 4. The division unit 10 performs the operation of dividing the code generated by the time-code conversion ers 9 and proportional countable time interval, the result of the counter value counting 4. IPT is mapped digital display unit 11. 2 yl. o (9

Description

The invention relates to the field of heat engineering measurements and can be used, for example, when sorting piezoquartz temperature transducers according to the value of their thermal inertia indicator at manufacturing plants, as well as in laboratory conditions.

The purpose of the invention is to increase the measurement point of the thermal inertia index by reducing the mean square measurement error.

Figure 1 shows the block diagram of the meter; Fig. 2 shows timing diagrams explaining the operation of a meter device.

The meter contains a driver 1 pulses, two ohic elements I 2 and 3, a logarithmic reversing counter 4, a generator of 5 clocks, pulses, a dispenser 6 clocks, two RS-flip-flops 7 and 8, time-code converter 9, block

10 divisions and a digital display unit 11 - 25 from the output of the imaging unit 1 to the input of the lation.

The meter works as follows.

The thermoconver under investigation is connected to the meter input, the value of the thermal inertia indicator of which is to be measured. The thermal converter is subjected to heat. Under conditions of a regular thermal regime (after a heat pulse), the output frequency F (t) varies according to the law of the damped exponent with a zero steady-state value (Fig. 2a).

- Shaper 1 converts the output frequency of the thermocouple into square impulses, which, through logic gates And 2 and 3, acting as keys controlled by triggers 7 and 8, respectively, are fed to the input and subtraction of logarithmic reversible counter 4, i

The distributor 6 clocks, which is a conventional decoder (demultiplexer), together with the generator 5 clocks performs the formation of two time intervals of duration Dg (Fig. 2c, d). during which the counting of the number of pulses N {and N by a reversible counter 4 (Fig. 2e, e), as well as a delay operation HIly temporarily about an interval from,

thirty

the counter 4. At the output of the trigger 7, a single impulse of duration & t is generated, which is converted into a code arriving at the second input of dividing unit 10 using the time-code converter 9.

The appearance of a pulse at the fourth output of the distributor 6 transfers 35 to the zero state trigger 8, which stops the arrival of pulses from the driver 1 to the subtracting input

counter 4.

i

40 After the end of the counting of pulses at the output of the reversible counter 4

 -i / N1 h

the code of the number 1Л (---) is formed, which is fed to the first input of the block

45 th division. The division unit 10 performs the operation of dividing a code proportional to the time interval fit to its second input from the output of the time-code converter 9, to

50 result of counter counting 4. At the output of dividing unit 10, a code is formed that is proportional to the thermal inertia indicator of the thermal conversion under study 55

ат - & lnn (N, / Na)

This code is displayed by a digital display unit 11.

ten

6190714

bearing to the first at the time (.g / 3, at which the minimum value of the mean square error of measurement of the thermal inertia index is reached.

The impulse at the first output of the distributor 6 translates the trigger. 7 into a single state, whereby the pulses from the output of shaper 1 through element I 2 begin to flow to the addition input of counter 4. The next pulse, generated at the second output of the distributor 6, translates the second trigger 8 into single state at one time. At the same time through the element And 3 on the subtracting input of the counter 4 begin to receive pulses from the output of the imaging unit 1.

At the third outlet of the distributor 6, a pulse appears after a period of time Dg SC. It brings the trigger 7 to the zero state and thereby stops the flow of pulses.

15

20

the counter 4. At the output of the trigger 7, a single impulse of duration & t is generated, which is converted into a code arriving at the second input of dividing unit 10 using the time-code converter 9.

The appearance of a pulse at the fourth output of the distributor 6 brings the trigger 8 to the zero state, which stops the arrival of pulses from the driver 1 to the subtracting input

counter 4.

i

After the end of the counting of the pulses at the output of the reversible counter 4

 -i / N1 h

the code of the number 1Л (---) is formed, which is fed to the first input of the block

th division. The division unit 10 performs the operation of dividing a code proportional to the time interval fit to its second input from the output of the time-code converter 9, to

the counting result of the counter 4. At the output of block 10 of the division, a code is formed that is proportional to the thermal inertia indicator of the thermal conversion under study

ат - & lnn (N, / Na)

This code is displayed by a digital display unit 11.

Claims (1)

Formula of five arr et e and A thermal inertia index meter for frequency thermocouples containing a clock pulse generator, a first trigger and a pulse shaper, the output of which is connected to the first inputs of two logic gates AND, the outputs of which are connected to the addition and subtraction inputs of a logarithmic reversing counter, the output of which is connected to the first input of the division unit , the display unit, the input of which is connected to the output of the dividing unit, while the output of the first trigger is connected to the second input of the first logical lementa And, characterized in that, for the purpose of xgo9071 To improve the measurement accuracy of the thermal inertia indicator by reducing the mean square measurement error, a second trigger has been introduced into it,  time-code converter and clock distributor, whose input is connected to the output of the clock generator, the first and second outputs are connected respectively to the first inputs of the first and second flip-flops, and the third and fourth outputs are connected respectively to the second inputs of the first and 15 second triggers, first output the trigger through the time-code converter is connected to the second input of the division unit, and the output of the second trigger is connected to the second input of the second logic element I. ten but III and II II and I I I 11 It