SU1716451A1 - Stroboscopic method for shaft rotation rate and stroboscopic tachometer implementing thereof - Google Patents

Abstract

The invention relates to a measuring technique and can be used to measure shaft rotation parameters. The aim of the invention is to enhance the functionality and increase the information content. At the moment when the shaft 2 passes the zero angular position, the optical mark 11 is opposite the zero value of the scale 10. At this time, a pause t is generated between flashes of light of a certain duration. During the time t: 0, the unlit label will rotate by an angle, where CO is the angular velocity of rotation of the shaft. Measur. Well, the arc of the unlit area, you can determine the speed of rotation of the shaft, and the position of this arc relative to the zero position of the shaft - the direction of rotation. 2 sec. f-ly, silt

Description

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The invention relates to a measurement technique and can be used to determine rotation parameters. The aim of the invention is to enhance the functionality and increase the information content.

FIG. 1 is a diagram of a c-tachometer; in fig. 2 - time diagrams of his work.

The strobachometer contains a sensor 1 of zero angular position of shaft 2, acting on sensor 1, element 3, located on the lateral surface of shaft 2, comparator 4, controlled synchronizer pulse generator 5, pulse shaper 6 (duration pg. Pause between flashes), block 7 a pulse counter, which includes a register, a decoder and a digital indicator, a control unit 8 for a pulse illuminator 9, a circular scale 10 and an optical mark 11. The output of the sensor 1 is connected to the input of the comparator 4, the output of the comparator 4 is connected to the start input and the generator 5 and the counting input C of the counter 7, the output of the generator 5 is connected to the input of the generator 6 and the input R of the counter reset to O, the output of the generator 6 is connected to the input D of the control of the generator 5, the input V of the control of the counter 7 and the input of the block 8, the output of which is connected to the input of a pulsed illuminator 9. illuminating the mark 11. The circular scale 10 is arranged concentrically in the plane of the shaft end. In the strobothometer, sensor 1 is installed so that the sync-pulse can be generated with the moment the shaft passes the zero position, for which the angular position of the zero division of the dial and the zero angular position of the optical mark 11 is assumed. For a description of the operation, we assume that the strobometer (Fig. 1) The counter unit 7 has the following control logic: at the input C, information is entered into the counter by a positive front of the input signal; the account is resolvable at the zero signal at input V; data recording in the register occurs on the positive edge of the signal at the input V; the counter is reset by a zero signal at input R. In the initial state, when the shaft is at rest, and its angular position does not coincide with zero, the output signals of all nodes (

and the blocks remain unchanged, with the signals at the output of sensor 1 and comparator 4 being zero, and at the outputs of the remaining nodes and blocks (, 8 and 9) the ones (Lig.2, time t).

The method is implemented as follows.

When the shaft 2 rotates, when the element 3 passes in the working area of the sensor 1 - the shaft 2 at this moment passes the zero angular position — a narrow triangular-shaped impulse U is generated at the output of the sensor 2. As a result, a rectangular pulse is generated at the output of the comparator 4. Since the prohibiting unit voltage from the output of the imaging unit 6 is applied to the control input V of the counter 7, the state of the counter does not change when the pulse C is received from the comparator на at its input. The front front 11ts. the pulse is started by the shaper 5, since a single Ug is applied to its control D input - the resolving voltage is output from the shaper 6. The clock from the shaper 5 output is reset to zero state 7 and the shaper 6 is started. A output Ug of negative is generated at its output polarity duration tfl. In this case, the output voltage of the block 8 switches from single to zero and is stopped by the flash generator by the illuminator 9 at time t, as a result of which an unilluminated part of the stroboscopic picture at the shaft end — the arc (sector) begins; the input V of the counter 7 and the control input of the imager 5 from the output of the block 6 are supplied with zero voltage - for the counter 7 it is enabling, and for the Imager 5 it is inhibiting. If the speed Q of rotation of the shaft 2 is less than the calculated value c00, then during the period c0, the shaft 2 will turn by an angle of 1 & i.e. he will not pass the next zero position. Since no signal is received from sensor 1, the state of the counter will remain zero. Upon completion of the pulse generation by the shaper of a positive edge of the signal at the input V of the counter 7, the zero state of the counter is written into the register and indicated by the indicator -. At the input of the V counter is set

prohibitory signal. A single signal from the output of the imager 6 is amplified by the mos. The block 0 and supplies power to the illuminator 9, which turns on and begins the formation of the illuminated gi / sector (sector) of the stroboscopic picture. With further rotation of the shaft, when it makes a full turn, the formation of the illuminated arc (sector) ends, ends, "the stroboscopic formation. Which picture. Its unlit part is located from the zero division of the scale in the direction in the direction of rotation of the shaft and has an angular size) t

corresponding rotational speed: C00

o-vir

When the shaft, having made a complete rotation, passes the zero angular position again, the sensor 1 and the comparator 4 are again triggered, since at the input V of the counter 7 there is still a single inhibitory voltage, the zero state of the counter remains, and the driver 5 starts and starts the driver 6 - the re-forming of the unlit part of the stroboscopic picture begins, at the input V of the counter 7 a zero-resolution (from the driver 6) voltage is set, the driver 5 is blocked by the same voltage. Let us suppose that from this moment the speed of rotation of the shaft increased and exceeded the value of C00. FIG. 26 shows the case when the CO rotational speed of the shaft is such that during the time c0, the shaft makes more than three (but less than four) revolutions. Since the sensor 1 and the comparator 4 trip three times, the number 3 is entered into the counter 7, i.e. . The former does not start, and the former 6 generates a negative pulse of duration c0, the generation of which ends on the fourth rotation of the shaft. Output voltage pho

The universalizer 6 abruptly changes from zero to one, as a result, the counter data is recorded in the register of block 7 from the counter and the number 3 is indicated by the indicator; the illuminator 9 is turned on, which remains on, as usual, until the shaft has passed the zero angular position. As a result, and at 03 W0,

an unlit arc (sector) of a stroboscopic picture with an angular size of cp1 equal to a part of (pM) th revolution of the shaft, in this example of the fourth, although the optical marker is actually unlit, turned on the angle

Cf 2im +

)

“-

s

0

five

0

five

during rotation

2

Thus, count the speed g. ..

shaft can

If1

WITH R p n + --- no) nCiX + CO t t-l 1-l

U0 U0

The position of the unlit arc relative to the zero position of the shaft determines the direction of rotation.

Claims (2)

1. A stroboscopic method for determining the speed of rotation of a shaft, consisting in the illumination of an optical mark, applied to the end of the shaft, by a sequence of flashes of light and measuring the number of whole revolutions of the pa-known time interval, with the fact that in order to extend the functionality and increase the information content, the time interval is measured -th rotation of the shaft on (n + 1) whole  rotation, synchronize the start of the counting of the intervals rQ and tn-H with the moment when the shaft passes its zero position, and the illumination of the optical mark is carried out by light flashes of duration t (with s 0 0 five and frequency with following equal f, f & / (n + 1), where fg is the shaft rotation frequency, and the rotation speed 6) of the shaft is determined from the ratio (C0 2 "p / s0 + C / s0, where Cf is the angular size of the unlit, arc stationary stroboscopic picture obtained at the end of the shaft, and the direction of rotation is determined by the position of the fixed stroboscopic pattern relative to the zero position of the shaft. 2. A tachometer for determining the speed of rotation of the shaft, containing an optical mark applied to the end of the shaft, and a serially connected control unit and a pulsed illuminator, as well as a pulse counter, that is additionally contains a zero angular position sensor of the shaft, a comparator, a sync pulse shaper, and a pulse width former; the zero angular position sensor output is connected to the comparator input, the output of which is connected to the synchroimp pulse trigger input lsa and the count input of the pulse counter. the output of the sync pulse generator is connected to the reset input of the counter to zero and the output of the pulse length generator, the output of which is connected to the control input of the sync pulse generator, the count input of the pulse counter and the illuminator control unit input, and there is a circular scale at the shaft end . S) a) a) & yy