SU1103151A1 - Method and device for measuring shaft rotation speed - Google Patents

Abstract

1. A method of measuring the speed of rotation of a shaft by forming a measurement interval, the duration of which is a multiple of the duration of the shaft rotation period, filling the measurement intervals with pulses of the reference frequency, counting the number of these pulses in the current measurement interval, subsequent filling and converting this number into analog form during the subsequent measurement interval , characterized in that, in order to increase accuracy and speed in a wide measuring range, after filling In the measurement interval, the reference frequency pulses produce a sequential decrease in the filling frequency by K times, where K is any predetermined integer number, and further filling of the measuring interval with pulses from each frequency until the end of the measuring interval, and the sum of the number of transmitted pulses is the lowest filling frequency and the numbers N / k as well as the number of falls occurring are memorized. . 2. A device for measuring the speed of rotation of the shaft, comprising a sensor, a reference frequency generator, a trigger, serially connected first counter, first memory register and digital-to-analog converter, rewrite and reset pulse shaper, the rewriter output of which is connected to the overwrite input of the first memory register, and the reset output is connected to the input 4 reset of the first counter, the outputs of which are connected to the inputs of the AND circuit, so that, in order to increase accuracy and speed, with a wide range of a multiplexer, a second re-f / 1 memory hub, a second and a third counter, the counting input of the second counter is connected to the output of the reference frequency generator, and the outputs of the second counter are connected to the signal inputs of the multiplexer, the output of which is connected to the counting input of the first counter, the input of which is connected to the trigger output, when etsm the installation input of the trigger, as well as 0. the counting input of the third counter is connected to the output of the And circuit, the reset inputs of the second counter, the third U of the counter and the trigger are connected the reset output of the pulse former, the input of which is connected to the output of the sensor, and the output of overwriting, with the input of the second register of the memory, whose inputs are connected to the control inputs of the multiplexer and the outputs of the third counter, and the outputs of the second memory register -channel-new converter.

Description

The invention relates to a measurement technique and can be used for precision measurement of angular velocity. There is a known method for measuring the speed of rotation of a shaft by forming pulses, the period of which is equal to the period of rotation of the shaft, the subsequent conversion. these pulses are pulses of a stable Ws-second area and the selection of the average value of the received pulses l. A device implementing this method contains successively connected frequency sensors, a driver, an amplitude limiter, an averaging unit, as well as a crystal oscillator and a second coincidence circuit l. This method and device for its implementation have low accuracy at high shaft accelerations due to the inertia of the average pulse value extraction circuit, the time constant of which is chosen based on the minimum shaft rotation speed. The closest to the proposed technical essence and the achieved result is a method of measuring the shaft rotation speed, according to which a measuring interval is formed, the duration of which is equal to two periods of shaft rotation, the measurement interval is filled with standard frequency pulses, the number of these pulses in the current measurement is calculated interval, and then memorize and convert this quantity into analog form during the subsequent measuring interval 2J. A device that implements this method contains a series-connected sensor, amplifier, trigger and & 1idt, the first and second triggers, the OR logic circuit, a rewriter and reset pulse shaper, performed on two single-oscillators, successively connected reference frequency generator, blocking circuit, a counter, a memory register and a digital-to-analog converter, a multivibrator, the overwriting output of the overwriting and resetting pulse generator is connected to the overwriting input of the memory register, and the reset output is connected to the reset input of the counter, the output of which is connected to the inputs of the circuit I, whose output is connected to the second input of the blocking circuit, the second output of the second trigger connected to the third input of the blocking circuit, and the output of the Schmidt trigger connected to the input of the multivibrator, whose outputs are connected respectively to the input of the amplifier and the second input of the OR circuit 2. The disadvantage of the known method and device is low accuracy with a wide range of variation of the controlled shaft rotational speed due to the limited number of digital-ana cuts. Ogove converter. The purpose of the invention is to improve the accuracy and speed with a wide range of measurement of the speed of rotation of the shaft. The goal is achieved in that according to the method of measuring the shaft rotation speed by forming a measurement interval, which is a multiple of the duration of the shaft rotation period, filling the measurement interval with N pulses of the reference frequency, counting the number of these pulses in the current measurement interval, then storing it and converting this number into analog the form during the subsequent measurement interval, after filling the measurement interval with M pulses of the reference The frequency is filled down by K times, where K is any predetermined integer number, and further filling of the measurement intervals-pulses of each frequency until the end of the measurement interval, moreover, the sum of the number of transmitted pulses of the lowest frequency and K / K, and also, the number of lows occurred is remembered. A device that implements the method, containing a sensor, a reference frequency generator, a trigger, a first counter connected in series, a first PS1m register and a digital-to-analog converter, a rewrite and reset pulse shaper, the rewriter output of which is connected to the overwrite input of the first memory register, and the reset output is connected to the reset input of the first counter, the outputs of which are connected to the circuit inputs and, additionally, a multiplexer, a second memory register, a second and a third counters, the counting input the second counter is connected to the output of the reference frequency generator, and the outputs. The second counter is connected to the signal inputs of the multiplexer, the output of which is connected to the counting input of the first counter, the input of which is connected to the output 4 flip-flops, the installation input of which, as well as the counting input of the third counter are connected to the output of the And circuit, the reset inputs of the second counter, the third counter and the trigger is connected to the output cm of the reset of the pulse former, the input of which is connected to the output of the sensor, and the output of the rewriting is connected to the rewriting input of the second memory register, the inputs of which are connected to the control inputs of the mule tipleksora vyho rows and the third counter, and outputs second-register memory are connected to inputs Auto rymi digital to analog transformations verters. FIG. 1 shows a block diagram of the device} in FIG. 2 is a time chart illustrating the operation of the device. A device for measuring the speed of rotation of the shaft, which implements the proposed method, includes a sensor 1, a generator of the reference frequency 2, the first, second and third counters 3, 4 and 5, the overwriting pulse shaper and; throw 6, multiplexer 7, the first and second memory registers 8 and 9, circuit 10. And, trigger 11 and digital-analog converter 12. Digital-analog converter 12 can be made on the basis of operational amplifier 13, reference voltage source 14 and first and second resistor matrices 15 and 16. Device works following image. Sensor 1 connected to the shaft generates pulses whose period is equal to the period of rotation of shaft 3 (Fig. 2, IJ out 1). On the positive front of these pulses, the rewrite and reset pulse shaper 6 forms a short rewrite and reset pulse (Fig. 2, Ugbix overwrite, U gjiix. 6 reset). The reference frequency generator 2 runs continuously and its output pulses with frequency 2i (Fig. 2, O 2) are fed to the input of the second counter 4, the outputs of which form a grid of frequencies with frequencies i, f / 2, i / 4, and so on. d. (Fig. 2, tJgb ,, 4). After the occurrence of a reset pulse (Fig. 2. Ueb ,, .. b reset), the first, second third counters 3, 4 and 5 and the trigger 1 are reset to the zero state. Zero levels of signals at the control inputs of multiplexer 7 ensure the connection of the highest output frequency of the second counter (i.e. f) to the counting input of the first counter 3 (Fig. 2.11 bc | x 7). Thus, the first counter 3 at the beginning of each period of the output signal of sensor 1 produces - counting the pulses of frequency i. At time i (Fig. 2), logical units are set in all sections of the first counter 3, i.e. it overflows (Fig. 2, iJebm). This state is detected by the first circuit AND 10, (Fig. 2, Ug | ,,, (10). The appearance of the signal at the output of the first AND 10 leads to switching of the trigger 11 (Fig. 2, Ugj, | 11) and writing the number one to the third counter 5 (Fig. 2, Ujtix, 5). The output signal of the trigger 11 sets the high bit of the first counter 3 to the state of the logical unit (Fig. 2, 3- 3), and this state will not change further until the trigger 11 is reset. The code of the number one output of the third counter 5 connected to the control inputs of the multiplexer 7 leads to Connecting to the counting input of the first counter 3, the outputs of the second discharge of the second counter 4, i.e., starting from time i, the first counter 3 counts the pulses, the frequency of which has decreased twice and became equal to i / 2. Next, the first counter 3 continues counting until all bits are filled with units, except the high bit, which is forcibly held in a single state by trigger 11. Filling one digit of the first counter with units of all bits 3 leads to the introduction of another one into the third counter, which leads to a decrease in the frequency them The pulses at the counting input of the first counter 3 are doubled, and then the process in the device repeats until the end of the period of the output signal of sensor 1 is overwritten by the overwrite signal (Fig. 2, Uebi; (, b) overwritten); rewrites into the first 8 and second 9 memory registers that control the first 15 and second 16 resistive matrices of the D / A converter 12. The output voltage of the device, as follows from the D / A converter circuit 12, is equal to where the UQ is output source voltage reference voltage 14; - resistance of the first resistive matrix 15; - resistance of the second resistive matrix. 16. For normal operation of the device, the resistance of the second resistive matrix 16 is chosen proportional to where i is the number of variable filling frequencies, i.e. the reading of the third counter 5 at the moment of the end of the period of the output signal of the sensor 1. The resistance of the first resistive matrix 15 is chosen proportional to the number M, where M is the number of filling pulses of the highest input frequency of the first counter 3, rounded to the number of bits of this counter, i.e. the number M is the readings of the first counter 3 at the moment of the end of the period of the output signal of the sensor 1. Thus, g 1, -b. m where KO is the coefficient of proportionality.

 In this case, since the product 2. M is proportional to the duration of the measured period, the output voltage of the device is proportional to the speed of the shaft.

After the rewriting of information from the first 3 and third 5 counters to the first 8 and second 9 registers of memory, the pulse shaper, rewrite and reset 6, generates a reset pulse of counters 3,4 and 5 and trigger 11, and the measurement process starts first . At the same time, in the first 8 and second 9 memory registers, and consequently, at the output of the device, the signal corresponding to the shaft rotation speed measured during the previous period of the sensor output signal is stored.

Thus, by means of a sensor associated with a rotating shaft. A measurement interval is formed, the duration of which is an integer different from the period of rotation of the shaft. At the beginning, the measurement interval is filled with pulses of frequency i. If the number of filling pulses has reached the number K (in the case of counting by a binary counter, it can be N 2, where n is the number of bits of this counter), and the measurement interval has not finished yet, the filling frequency is reduced to K times, where K is the base of the counter binary counter. The filling of the measuring interval with N pulses of frequency i is equivalent in time to filling N | K with pulses of frequency i / K. Therefore, the counter counting the number of pulses of filling measuring interval with frequency i / K begins its count not from zero, but from the value of N / lc. After the arrival of the number of pulses N-- with frequency f | j, the state of the counter is similar to the state after the arrival of pulses with frequency i. Further, the frequency is further reduced by a factor of K and the process of filling the measurement interval continues until it ends. At the end of the measuring interval, the sum of the number N / K and the number of low-frequency filling pulses arrived was recorded in the counter. Thus, the sum obtained multiplied by the period of the following low frequency pulses is equal to the duration of the measured interval. Therefore, to determine the actual speed of rotation of the shaft, it is necessary to memorize and transfer this amount and the number of frequency drops that unambiguously characterize the value of the period of the lowest frequency to the digital-to-analog converter.

When using the proposed method, at any frequency of rotation of the shaft, an automatic switching of the magnitude of the filled frequency occurs, which prevents deterioration of accuracy when the frequency of rotation of the shaft increases, i.e. provides a significant improvement in device accuracy.

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Claims (2)

1. The method of measuring the shaft rotation speed by forming a measuring interval, the duration of which is a multiple of the duration of the shaft rotation period, filling the measuring interval and pulses of the reference frequency, counting the number of these pulses in the current measuring interval, then filling and converting this number into an analog form during the subsequent measuring interval , characterized in that, in order to improve accuracy and speed with a wide measurement range, after filling out of the measuring interval U by pulses of the reference frequency, the filling frequency is sequentially reduced in K times, where K is any predetermined integer, and further filling the measuring interval I with “7G pulses of each frequency” until the end of the measuring interval, and the sum of the number of transmitted pulses of the lowest filling frequency and the numbers / k, as well as the number of decreases remembered. . 2. A device for measuring the shaft rotation speed, comprising a sensor, a reference frequency generator, a trigger, a first counter, a first memory register and a digital-to-analog converter, an overwrite and reset pulse generator, the overwrite output of which is connected to the overwrite input of the first memory register, in series and a reset output coupled to the reset input of the counter lane Vågå which outputs are connected to inputs of the aND circuit, Otley sistent in that in order to improve the accuracy and _Λ § performance over a wide range of measurement , a multiplexer, a second memory register, a second and third counters are introduced into it, and the counting input of the second counter is connected to the output of the reference frequency generator, and the outputs of the second counter are connected to the signal inputs of the multiplexer, the output of which is connected to the counting input of the first counter, the input of which is connected with the trigger output, while the trigger installation input, as well as the counting input of the third counter, are connected to the output of the AND circuit, the reset input of the second counter, the third counter and the trigger are connected to the reset output pulse generator, the input of which is connected to the sensor output, and the re-recording output is with the overwrite input of the second memory register, the input of which is connected to the control inputs of the multiplexer and the outputs of the third counter, and the outputs of the second memory register are connected to the second inputs of the digital-to-analog converter.