SU1427182A1 - Weigher for metering speed of flow of fluid and loose materials - Google Patents

Abstract

The invention relates to weighing technology and allows to improve the accuracy of measurements by taking the averaged weight values at fixed moments. The signal of the load cell after the analog-digital converter 1 is fed to the adder 14, the reader 3 and to the register 2 for storing the initial value. At the same time, counter 6 is reset, and the number n, which determines the number of measurements when counting is averaged, is written into subtracting counter 1I. The summation of the n values is carried out in the adder 14, synchronized by the generator 5, the difference between the values of the register 2 and the subtractor 3 is compared with the value determined by the threshold element 4. When the counter 1I overflows, the output of the former 10 appears, which sets the trigger 12 O, prohibiting the operation of adder 14 and permitting the transfer of its final value to the subtractor 13. The signal from the output of threshold element 4 or when the counter 6 overflows the circuit OR 15 allows writing to the register 2 of the new current value sensor signal, the information about the duration of the measurement cycle is transferred to the divider 7 and the counter 6 again purified. At the same time, the number n is again recorded in counter 11, and trigger 12 is cocked, clearing the adder 14. Then the cycle repeats. The difference of the measurement series is determined in the subtractor 13 and transferred to the divider 7, in which the flow rate of the material is determined. The result is transmitted to the recorder 8. 2 Il. SL

Description

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This invention relates to a weight measuring technique, and may be used. Used to measure the flow rate of flowing and flowing materials from a tank or hopper mounted on scales with built-in primary transducers of force in devices for monitoring and stabilizing the performance of dispensers of continuous action.

The purpose of the invention is to increase the measurement accuracy by taking average readings of the values of the force transducer signals at fixed points in time.

, Figure 1 shows a block diagram of the device; figure 2 shows timing diagrams.

The weight meter of the rate of expiration of materials contains an analog-to-digital converter (ADC) 1, register 2, subtractor 3, threshold element 4, generator 5, counter 6, divider 7, recorder 8, driver 9, pulses, and additional driver 10 pulses, additional counter 11, trigger 12, additional subtractor I3, adder 14 and circuit OR 15.

The weight meter for the flow rate of materials runs as follows.

ADC 1 converts, the signal from the primary power converter is about the instantaneous value of the measured weight to the code at fixed points in time with a period T determined by the frequency of the generator 5. At the initial moment of time, register 2 records the initial weight from which the measurement, the counter b is set to zero, the additional counter 11 records the number n in the return code, which determines the number of measurements when averaging the count, trigger 12 is set to state 1 and enables the adder 14.

As the readings on the output of the A / D converter 1 change, a signal proportional to the difference between the initial and current weight values appears at the output of the subtractor 3. At this time, the counter 6 counts the time intervals with the period Tp, given by the generator 5, and the additional counter 11 counts the number of measured values of the weights arriving at the input of the adder

14, with the same period. When the additional counter 11 overflows, an additional signal appears at the output of the additional pulse shaper 10, which sets the trigger 12 to the state O, which prohibits the operation of the adder 14. In the latter, the sum of a series of n consecutive measurements is recorded

weight of P; and is transmitted to ui

Complementary subtractor 13.

When the signal at the output of the subtractor 3 reaches the specified value

(Rro) the threshold element 4 is triggered, and the signal from its output through the circuit OR 15, the counter 6 transmits information about the measured time interval N Tf to divider 7 and then resets to zero. At the same time, the new number n is added to the additional counter 11 and the G2 trigger is set to state 1, i.e. the cycle repeats. At the same time, the adder is cleared and starts summing up the next series of weight values.

The calculation of the rate of discharge of material Q is made by the formula:

where P; P, 44i are the average weights, respectively, at the beginning and at the end of the measurement interval; To p-Tr-scale factor, pre-set in the divider 7.

The difference used in the formula (1) is calculated in the additional subtractor 13 by subtracting the subsequent value of the sum of the series from n consecutive measurements of the values of the weight from the preceding one. in the additional subtracter 13. Subtraction is done at the end of each cycle of summation at trigger 12 in the state O. On the same signal, the pro-. transfer of the result of the subtraction to the divisor 7 is carried out, the subsequent case

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out and in and out of the final result in the registrar 8.

If the measured flow rate is very small and when the meter 6 is completely filled, the signal from the output of the subtractor 3 does not reach the threshold value, then when the meter 6 is full, the output of the pulse former 9 produces a pulse transmitted through the OR circuit 15 to the inputs of the register 2, trigger 12 , counters 6 and 11. According to this impulse, the operation of the device is similar to that described. Calculation of the rate of expiration It is performed using information about the average weight increment for the maximum interval, time.

Claims (1)

Invention Formula A weight meter for the flow rate of flowing and bulk materials containing an analog-to-digital converter, one of the inputs of which is connected to the primary weight converter, and the output is connected to the first inputs of the subtractor and the register, the output of which is connected to the second input. the input of the threshold element, the generator, SV 5 7; Q 5 0 5 n 82 It is connected with the first input of the counter, the output of which is connected to the input of the pulse former and the first input of the divider, the output of which is connected to the recorder, which, in order to improve the measurement accuracy, a series-connected adder and additional subtractor are entered into it, as well as an additional counter, additional pulse shaper, trigger and OR circuit, the first input of which is connected to the output of the threshold element, the second input to the output of the pulse shaper, and the output is connected to the first input of the trigger Serial and with the second inputs of the register, the counter and the additional counter, the first input of which is connected to the generator, and the output through the additional pulse shaper is connected to the second trigger input, the output of which is connected to the second inputs of the additional subtractor divider and adder, the first input of which is associated an analog-to-digital converter output, the second input of which is connected to the generator, in addition, the output of the additional subtractor is connected to the third input of the divider.