SU1200126A1 - Flowmeter - Google Patents

Abstract

The invention is used in the development of flow meters for gases and liquids, and allows for improved accuracy and noise immunity and improved flow meter functionality. For this purpose, the trigger 12 is set to one when, after switching on, the flow rate reaches the minimum allowable value at which the measurement accuracy is guaranteed. The pulses from the output of the imager 2 are fed to the input C of the trigger 12, the input of the trigger 17 and the pre-installation input of the divider 16. If the flow rate is less than the minimum allowed, the output of the divider 16 appears to overflow pulses, which set the trigger 17 to the zero state. With the arrival of the next pulse from the output of the generator 2, the state of the trigger 17 is transferred to the trigger 12, the trigger 17 is set to O) the one state. Postus pulses are fed to the input of the addition of adder 14,

Description

the measurement result is indicated by the indicator 18. When trigger 17 is set to the zero state and, accordingly, the trigger.12 the element 13 1200126 is closed and the summation pulses do not pass to the adder 14. As a result, false information is excluded. 1 il.

The invention relates to instrumentation and can be used in the development of flow meters for gases and liquids.

The purpose of the invention is to improve the accuracy, noise immunity and enhance the functionality of the flow meter.

The drawing shows a diagram of the flow meter.

The tachometer converter is connected to a shaper of 2 pulses. The outputs of the imager are connected: - to the inputs of trigger 3, the output of which is connected to the input of the one-shot 4. The generator 5 of the reference frequency is connected to the output And 6, the second input of which is connected to the output of the trigger 3. The output of And 6 is connected to the counting input of the counter 7 the input of which is set to zero is connected to the output of the one-vibrator 8. The first frequency divider 9 with a variable division ratio, the counting input is connected to the frequency generator 5, the preset input to the output of the one-vibrator 10, and the output to its about the entrance. The register 11 with its information inputs is connected to the output of the counter 7, and the information recording input is connected to the output of the one-vibrator 4 and the input of the one-vibrator 8. The third trigger 12 is connected with its output to the second input of the second element I 13, the first input of which is connected to the output of the divider 9 and the output - to the input of the accumulating adder 14. The information inputs of the adder 14 are connected to the outputs of the register 11, and the Bxofl is set to zero with the outputs of the presetting circuit 15 and the input R of the third trigger 12.

The second frequency divider 16 with a variable division factor is connected by its counting input to the output of the reference frequency generator 5, the preset permission input to the clock input of the third trigger 12, to the second input

the driver 2 and the input S of the second trigger 17. The output of the divider 16 is connected to the clock input of the second trigger 17, the input D of which is connected to the zero potential, and the output of the input D of the trigger 12. The status of the adder is indicated by the indicator 18.

The information inputs of the pre-installation of dividers 9 and 16 are connected to the sources of logical levels forming the numbers N., and Nj.

The value of N.J is determined from the ratio

fc

Z N, -

f-y frequency of summing instantaneous flow values;

fg is the pulse frequency of the reference frequency generator;

Ng is the total division factor of the divider 9,

and the value of N is like

N

N,

Z N

in

where N is the total division factor of the divider 16; MHz is the minimum frequency of the signal, removed from the tachometer sensor. The device works as follows.

When the supply voltage is turned on, the presetting circuit 15 sets the zero position of the adder 14 and the trigger 12, thereby prohibiting the passage of the summation pulses from the output of the divider 9 to the adder 14 through the element 13. The signals generated by the tachometer converter go through the driver 2 to the trigger 3,

at the output of which there are impulses, whose duration is equal to the difference in the moments of arrival of adjacent pulses of the tachometer converter. This pulse opens the element 6 and the pulses from the generator 5 of the reference frequency arrive at the counting input of the counter 7, the accumulated code of which during the time of the pulse is equivalent to the instantaneous value of the mass flow. At the end of the counting of pulses (trigger 3 is set to the zero state, the pulse from the output of the one-shot 4 with some delay transfers the reading of the counter 7 to the register 11, and the pulse from the output of the one-shot 8 sets the counter 7 to the zero state. Simultaneously. Pulses from the output of the generator 5 reference frequencies arrive at the counting inputs of dividers 9 and 16.

A divider 9 with a single vibrator 10 serving to enter the number N., into divider 9 after each occurrence of a pulse at the output of the divider, forms a frequency divider with a variable (depending on the value of N) division factor. As a result, pulses appear at the output of divider 9, the frequency of which is equal to f. With this frequency, the summation of the result contained in register 11, accumulating adder 14, takes place.

Summation occurs only when the trigger 12 is in the single state, otherwise the pulses from the output of the divider 9 will not pass through the element And 13 and there will be no summation. The trigger 12 is set to one state only when, after switching on, the flow rate reaches the minimum allowable value at which the accuracy of the measurement is guaranteed. The pulse frequency is generated by the tachometer converter 1, with f being the same. These pulses from the output of the imaging unit 2 are fed to the input C of the trigger 12, the input of the trigger 17 and the input of the preset divider 16 to the state NT ,. If the flow rate is less than the minimum allowable, the frequency of the pulses is less, and at the output of divider 16, overflow pulses appear, which set the trigger 17 to the zero state.

With the arrival of the next pulse from the output of the driver 2, the state of the trigger 17 is transferred to the trigger 12, the trigger 17 is set to the one state and the divider 16 is set to the N state. As the flow rate increases, the frequency of the pulses of the tachometer converter increases. When fi f

ACh and p

the divider 16 does not overflow, there are no pulses at its output and the trigger 17 remains in a single state, which with the arrival of the next pulse is transferred to the trigger 12.

As a result, pulses from the output of the divider will begin to flow to the input of the addition of accumulating adder 14, in which the result of measuring the total flow will be formed.

The measurement result is indicated by the indicator 18. When the flow rate drops below the minimum allowable, the trigger 17 is set to the zero state, and the trigger 12, respectively, the Element And 13 closes and the summing pulses do not pass to the adder 14. As a result, false information is excluded .

Claims (1)

Invention Formula thirty A flow meter containing a tachometer transducer connected in series with it device, trigger and two one-shot, pulse counter, frequency generator, the output of which is connected to the first input of the first element, the second input of which is connected to the output of the trigger, and output to the counting input of the counter, the reset input of which is connected to the output of the second single-vibration, register, the inputs of which are connected to the output of the counter, and the input of the census to the output of the first one-oscillator, the accumulating adder, whose inputs are connected to the outputs of the register, the outputs to the digital indicator, the reset input to the output of the preliminary circuit of the unit, and the second element And, the output of which is connected to the input of the addition of the adder, characterized in that, in order to increase the noise immunity and enhance the functionality, it additionally introduced a third single vibrator, two triggers, two frequency dividers with a variable division factor, counting inputs 51200126 " the first and second dividers are frequency, and input S is connected to the input disconnected from the generator output of the presetting frequency setting, the output of the first splitter, the third input is connected to the first input of the second trigger and the second output of the Formago element I and the input the third single-device, the output of the second vibrator, the output of which is connected to the trigger, is connected to the input D of the third input of the permission of the preliminary trigger, the output of which is connected to the first divider installation, the output to the second house elevtorogo second divider is connected to the cop and taktovo- d, and input R - with you th input of the second flip-flop, the input D to the pre-swing circuit ustatorogo has zero potential urs-Novki.