SU1078454A1 - Displacement encoder - Google Patents

Description

The invention relates to the measurement of non-electrical quantities by electrical methods and can be used to measure linear displacements in automation and measurement technology.

A movement sensor with a digital output is known, which contains a discrete ruler with a bifillary winding, a reading unit in the form of two magnetic heads, and a measuring signal processing unit 1.

However, a known sensor has a low reliability, since when a power supply is turned off or when a power failure occurs, it gives false information, and, moreover, it has low accuracy due to the presence of a return wire in the bi-filar winding.

Closest to the proposed technical entity is a displacement transducer into a code containing a code information carrier, made in the form of a meander and connected to a high frequency generator, and a sensitive element consisting of a magnetic conductor and a measuring winding, an amplifier limiting device whose inputs are connected to the measuring winding, and the output with the first inputs of the elements And, the inputs of the amplifier of the imager are connected to the outputs of the high-frequency generator, the direct output of the amplifier -formirovatel ovally connected first and second single vibrators are connected to the second input of the first element I, the output of which is connected to the first input of a trigger, the inverse output of the amplifier-former is connected in series to the second input of the second element I, the output of which is connected to the second input of the trigger, the output of which is connected to the input of the counter, and the measuring winding of the sensing element is made in the form of two sections connected oppositely and placed on the extreme rods of the magnetometers rovoda made W-shaped with a gap between the rods at a pitch meander code information carrier .J

However, such a converter is characterized by low reliability, since during a short-term power failure it loses all the information about the movement, and when the power is restored, the phase shift of the supply voltage starts again from zero and not from the distance traveled by the distance converter.

The purpose of the invention is to increase the reliability of the displacement transducer.

The goal is achieved by the fact that a transformer containing a sine-wave voltage generator connected to the carrier of code information and to the inputs of the limiting amplifier, the direct output of which is connected to the first input of the first And second element, and the second output connected through the third and fourth one-shot with the first input of the second element And the outputs of the first and second

0 elements And connected to the trigger inputs, the output of which is connected to the first input of the counter, magnetic head connected to the amplifier inputs, pulse generator introduced, am5 amplitude detector, threshold elements, encoder - threshold element states, additional one-vibrators, decoder, registration unit, and the code information carrier is made in

0 as a planar or volumetric shaped meander of a stepped form with a variable cross-sectional area, the output of the amplifier is connected to a pulse shaper and with

5 amplitude detector, the output of which is connected to the inputs and threshold elements, the outputs of which are connected to the j inputs of the encoder, (N + 1) the outputs of which are connected through the corresponding additional one-vibrators to the inputs of the decoder, the output of the latter is connected to the second input of the counter, the output of which is t: o with the registration unit.

FIG. 1 shows the structures on the converter circuit /

FIG. 2 - plane profiled meander.

The converter comprises a sinusoidal voltage generator 1,

0 the carrier 2 of the code information, made in the form of a volumetric (Fig. 1) or a planar profiled meander (Fig. 2), a magnetic head 3, an amplifier 4, a driver 5

5 pulses, limiting amplifier 6, two chains of series-connected single-oscillators 7, 8 and 9, 10, And 11 elements and. 12, trigger 13, counter 14, registration unit 15, amplitude detection 16, threshold elements 17 and 18, state encoder of threshold elements 19, one-shot 20-22, and a decoder 23.

A sinusoidal voltage generator 1 feeds the code information carrier 2. The magnetic head 3 moves along the end of the code information carrier. The output of the magnetic head 3 is connected to the amplifier 4, the output

which is connected to the input of the driver 5. The output of the generator 1 of sinusoidal voltage is also connected to the input of the amplifier-limiter 6, the direct and inverse outputs of which

through two chains in series

connected one-shot 7.8 and 9, 10 connected to the first inputs of the elements 11 and 12, the second inputs of which are connected to the output of the driver 5. The outputs of the elements 11 and 12 are connected to the inputs of the trigger 13 and through the counter 14 to the input of the registration unit 15. The output of amplifier 4 is connected via an impedance detector 16 to the inputs of threshold elements 17 and 18, the outputs of which are connected to the input of the encoder of the states of the threshold elements 19, the outputs of which are connected to the input of counter 15 through single-oscillators.

The motion to code converter operates as follows.

When the carrier 2 of the code information supplied from the sinusoidal voltage generator 1 is moved, a sinusoidal voltage is induced in the magnetic head 3 with the frequency of the sinusoidal voltage generator, and the voltage of the carrier information 2 of the code information under the magnetic head 3 changes. last. The voltage from the output of the magnetic head is amplified by the amplifier 4 and shaper 5 and is converted into a square-shaped voltage, which is fed to the first inputs of elements 11 and 12, the second inputs of which are fed from two chains of serially connected single vibrators 7, 8 and 9, 10, which are triggered by a shaped limiting amplifier 6 with rectangular pulses from a sinusoidal voltage generator 1.

Thus, with the help of two elements 11 and 12, two channels are added, and at each phase voltage change on the magnetic head 3 relative to the voltage of the sinusoidal voltage generator 1, the one-shot pulses 8 and 10 through the trigger 13 are entered into the pulse counter 14. The operation of this part of the device is fully consistent with the operation of the prototype.

However, in case of unexpected interruptions in the supply of the supply voltage, after its restoration, the information in the pulse counter 14 disappears, which requires a constant return of the carrier 2 of the code information of the meander to the zero state. In addition, with repeated reversal of the movement of the displacement transducer, an accumulation of measurement error occurs, since at the back of the reverse, an error per unit of discreteness is possible.

To improve the reliability of the device and its dynamic measurement accuracy, both during power interruption and by eliminating the accumulation and error in the device, a second correction channel for motion estimation based on the amplitude principle of operation is used. The essence of it is that am5: the amplitude of the sinusoidal voltage induced in the magnetic head 3 depends on the density of the current flowing through the plane or volume square wave defined by its area

0 cross section.

The larger the cross-sectional area, the lower the density of the current creating a magnetic field flowing through the meander, and since the magnetic head 3 captures a certain limited square of the meander, the signal amplitude in the measuring winding of the magnetic head will also vary depending on

Q from the cross-sectional area of me-. Andra, and the larger area

the cross section of a planar or volume meander, the lower the current density and, accordingly,

5, the signal amplitude in the winding of the magnetic head 3 is smaller. This signal will have a 1 ms signal length within each square of the meander, and in places where its area changes

The Q of the cross section will abruptly change the signal amplitude.

The second assessment channel introduces a correction both after the interruption of the supply voltage 5 and in the non-operating mode, correcting the measurement results at specific points where the meandering cross-section changes. Transition from one stage

Q meander to another is carried out on the current-carrying edge of the meander, i.e. where the voltage phase changes in the magnetic head 3 (most conveniently to bind these points to the base) used in the counting system sensor (half, quarter of its scale, etc.). Since the magnetic head 3 can be at any of the meander steps when the power supply is interrupted, after recovery

power depending on the voltage amplitudes in the magnetic head 3 along the circuit: amplifier 4 - amplitude detector 16 will trigger the corresponding threshold elements 17 and 18, the number

which is one less than the number of meander steps. Depending on the index of the oldest of the triggered threshold elements, using the encoder 19, the corresponding one-shot 20-22 and decoder 23 records information into the pulse counter 14 and, with further movement of the carrier 2, the counting takes place by changing the phase of the voltage of the magnetic head 3 with single pulses.

Dialogically, the correction of the main measurement channel is performed in the normal mode of operation of the sensor. At the axial points, where the area of the cross section of the meander varies, the voltage amplitude in the winding of the magnetic head E also changes. At the same time, jtgpyroft element 17 and 18 will become higher and the recording signal on the other output of the encoder 19 In this case, the correlations from one-way FOVs 20-22 will work and the corresponding code in the counter will carry 14 pulses of 14 pulses through the decryptor 23,

a digital correction will be made in the pulse counter 14, which is registered by the registration unit 15.

Thus, the proposed converter has an increased reliability, since with an unexpected power outage after its occurrence, the subrange of finding the magnetic head is immediately determined above one of the planar or volumetric meander stages of the code information carrier and is digitally corrected.

Claims (1)

A CONVERSION OF MOVING TO A CODE containing a sinusoidal voltage generator connected to a code information carrier and to inputs of a limiter amplifier, the direct output of which is connected through the first and second single vibrators to the first input of the first element And, and the second output is connected through the third and fourth single vibrators to the first the input of the second element And, the outputs of the first and second elements And are connected to the inputs of the trigger, the output of which is connected to the first input of the counter, the magnetic head connected to the inputs of the amplifier, different The reason is that, in order to increase its reliability in operation, the following was introduced: *, a pulse shaper, an amplitude detector, threshold elements, a state element encoder of threshold elements, additional one-shot oscillators, a decoder, a registration unit, and a code information medium made in the form of a plane or volume profiled step-shaped meander with a variable cross-sectional area, the output of the amplifier is connected to the pulse shaper and to an amplitude detector, the output of which is connected to the inputs of N threshold elements, the outputs otorrhea connected to the N inputs of the encoder, (N + 1) outputs of which are connected through respective additional monostable with inputs of the decoder, the latter output is connected to a second input of the counter, the output of which is connected to a recording unit.