SU911139A1 - Self-excited oscillator meter - Google Patents

Description

(A) AUTOGENERATING. MEASURER

I

The invention relates to a measurement technique and can be used in instrumentation to control various electrical and non-electrical quantities.

A self-measuring meter with an inductive sensing element 13 is known. Its disadvantage is low noise immunity.

The closest in technical essence to the invention is av. a generator meter containing an auto generator, an inductive sensor, and a 2j recorder.

The drawbacks of the device are low measurement accuracy due to the effect on the result of various destabilizing factors, and also low noise immunity associated with the use of an amplitude-output sensor.

The aim of the invention is to improve the measurement accuracy and noise immunity of an auto-oscillator meter.

The goal is achieved by the fact that the meter is provided with a first controllable key, whose information input is connected to an inductive sensitive element, and an output to the input of an autogenerator, a reference inductance, a second controllable key, information input

to which is connected to the reference inductance, and the output to the input of the oscillator, a recalculated threshold unit, the input of which is connected to the output of the autogenerator, the third control key, information input of which is connected to the output of the autogenerator, and the output to the recorder's input, the fourth controlled key The information input of which is connected to the output of the recalculating threshold unit, controlled by a generator, the control input of which is connected to the output of the fourth key,

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Its output is to the input of the control unit, the first output of which is connected to the control inputs of the auto-generator and the counting threshold unit, the second output to the control inputs of the first and third keys, and the third output to the control inputs of the second and fourth keys.

The drawing shows a structural diagram of the autogenerator meter.

The self-oscillator meter suppresses the auto-oscillator 1, inductive, feel; element 2, the first controlled switch 3 connected between the oscillator 1 and the sensitive element 2, the reference inductance 4, the second controlled switch 5 connected between the reference inductance C and the oscillator 1, the recorder 6 , the third controlled key 7, the recalculating threshold unit 8 connected to the output of the oscillator 1, the fourth controlled key 9, the controlled generator 10 and the control unit t1, the first output of which is connected to the control inputs a togeneratora 1 and threshold scaler unit 8, the second output - to the control inputs of the first 3 and the third key 7, and the third output - to the control inputs of the second and fourth 5 9 klyuchb J.

The auto-generator meter works in two steps, as follows.

In the first cycle — the measuring one — by a command coming to the control input of the autogenerator 1, the supply voltage is turned on, and by the commands to the control inputs of keys 3 and 7, these keys are opened, and the inductive sensing element 2 is connected to the autogenerator 1 the output of which through the public key 7 is connected to the output of the recorder 6. In this case, the auto-oscillator 1 generates a packet of oscillations of a measuring radio pulse, the duration of which is determined by the turn-on time of the supply voltage of the auto-oscillator 1, and often This high-frequency filler is an unambiguous function of the monitored physical quantity converted to the inductance of the sensitive 2. The number of oscillations in the radio pulse is calculated using.

four

recorder 6 and is displayed in selected units.

The duration of the measurement pulse is variable and is chosen in such a way as to compensate for the frequency drifts of the autoheater caused by destabilizing factors. If, for example, the latter leads to an increase in the frequency

oscillation, the duration of the radio pulse is reduced so that the number of oscillations in the radio pulse for any fixed value of the monitored physical quantity is strictly defined.

Correction of the duration of the radio pulse is carried out in the second cycle of the autogenerator meter. At the same time, by commands received from the control unit 11 to the control inputs of the keys 5 and 9, the latter are opened and the reference inductance, -a output signal, is connected to the self-oscillator 1.

the recalculating threshold unit 8 through the public key 5 is fed to the control input of the controllable generator 10. In the considered clock, a reference radio pulse is generated.

the number of oscillations in it will become equal to the recalculation coefficient of block 8; a control impulse is formed at its output, the falling edge of which coincides with the end of the switch on command

supply voltage of the oscillator 1. The position of the leading edge of the control pulse depends on the oscillation frequency of the oscillator: as the frequency rises, the leading edge shifts to the left

and, accordingly, the duration of the control pulse increases, a decrease in frequency leads to a decrease in its duration. Since the value of the reference inductance is strictly

Claims (2)

is fixed, then the change in the oscillation frequency relative to a certain initial calibration value occurs only under the influence of destabilizing factors. With an increase in the frequency of oscillations and, accordingly, the duration of the control pulse, the pulse duration of the control generator will decrease for that time, while the number of oscillations in the radio pulse does not return to its original value. Similarly, there will be an increase in the duration of the radio pulse in the case of a decrease in the oscillation frequency of the autogenerator 5 torus under the action of destabilizing factors. The duration of the radio pulse corrected in this cycle is stored in the control unit 11 and is used later in the measurement cycle. The proposed autogenerating measurer provides high accuracy of measurements due to the elimination of the effect of destabilizing factors on the measurement result. At the same time | BUT, a high accuracy of measurement is achieved due to the use of a pulse-frequency measuring signal. Claims An auto-oscillator meter comprising an auto-oscillator, an inductive sensing element and a recorder, characterized in that, in order to improve measurement accuracy and noise immunity, it is equipped with a first control key, whose information input is connected to the inductive sensing element, and the output to the auto-oscillator input, reference inductance, second controlled key. 96 (the information input of which is connected to the reference inductance, and the output to the input of the oscillator, the scaling unit, the input of which is connected to the output of the autogenerator, the third controllable key, the information input of which is connected to the output of the autogenerator, and the output to the recorder's input, the fourth controlled a key whose information input is connected to the output of a recalculating threshold unit controlled by a generator, the control input of which is connected to the output of the fourth key, and the output to the input of the control unit, the first the output of which is connected to the control inputs of the autogenerator and the recalculating threshold unit, the second output to the control inputs of the first and third keys, and the third output to the control inputs of the second and fourth keys.Sources of information taken into account during the examination 1. Author’s USSR certificate No. 569993, class G 01 N 27/22, 1977-. 2. USSR author's certificate №463059, cl. G 01 N 27/86, 1975 (prototype).