SU1486806A2 - Device for monitoring vibrations - Google Patents

Description

The invention relates to measuring equipment and can be used to control vibration. The purpose of the invention - improving noise immunity - is achieved by eliminating false positives. The device consists of a second scaling amplifier 19, a key 20 and a summing amplifier 21. The selection of the gain of the amplifier 19 sets the ratio of the power of the periodic component to the noise power at which the random component will not lead to the multiple triggering of the threshold element 14. 1 Il.

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The invention relates to vibration measuring equipment and can be used to control vibration.

The purpose of the invention is to improve the noise immunity due to the elimination of false positives.

The drawing shows a block diagram of the proposed device for controlling vibration. ₍

The device contains serially connected vibrator 1, amplifier 2, first rectifier 3, first integrator 4 and indicator 5, series-connected limiter 6, second integrator 7, sampling and memory circuit 8, second differentiating link 9, second rectifier 10, third integrator 11 scaling the amplifier 12, the summing amplifier 13, the threshold element 14 and the actuator 15, as well as the first differentiating element 18, the input of which is connected to the output of the first integrator 4 and the second input of the summing amplifier 13, the third input of which is connected to the output of the first differentiating link 18, the serializer 16 and the reset circuit 17, the output of which is connected to the control input of the second integrator 7, are connected in series, the input of the driver 16 is connected to the output of the limiter 6, and memory, as well as serially connected second scaling amplifier 19, electronic switch 20 and second summing amplifier 21, the second input of which is connected to the output of amplifier 2, and the output - to the input of limiter 6, the output ne Vågå integrator 4 is connected to the second input of scaling amplifier 19 and the output of the limiter 6 is connected to the control input of the electronic key 20.

The device works as follows.

The signal from the output of the vibrator 1 through the amplifier 2 is fed to the input of the rectifier 3, is rectified and through the integrator 4 is fed to the indicator 5, which displays the average value of the measured value.

From the output of the integrator 4, the average value of the rectified voltage is fed to the first input of the summing amplifier 13. Through the first differentiating element 18 to the second input of the summing amplifier 13 receives a voltage proportional to the slew rate of the measured value.

The signal X (b) from the output of the amplifier 2 is fed to the second input of the second summing amplifier 21, the first input of which, through the scaling amplifier 19 and the electronic switch 20 receives the average value Υ _ο rectified voltage from the output of the integrator 4. The total voltage (ϋ) from the output a second summing amplifier 21 via the limiter 6 is input to the integrator 7 and the second input of the limiter 16. The output of the pulses 6 are formed of a positive polarity and _e with constant amplitude and a duration equal to the time exceeding total voltage Υ (ρ) of the zero level.

At the output of the second integrator 7 sawtooth pulses are formed with an amplitude A proportional to the duration of the pulses I _e , ₁

The shaper 16 forms a short pulse And, at the time of the decline of the front of the pulses And _about . Momentum I. | arrives at the control input of the circuit 8 sampling and memorization. During the pulse action, the signal amplitude, at the signal input of the circuit 8 · sampling and memorization is equal to A. This signal value is memorized by the sampling and memorization circuit 8 and through the second differentiating element 9, the second rectifierI ”

The driver 10, the third integrator 11 and the scaling amplifier 12 are fed to the input of the summing amplifier 13.

The pulse arrives at the input of the reset circuit 17, at the output of which a short pulse P _{g is formed} at the moment of the end of the pulse I |.

The pulse arrives at the reset input of the second integrator 7 and sets it to its original state, in which the signal at its output is zero.

At the output of the sampling and memorizing circuit 8, a stepped signal is formed, the value of which is proportional to the current value of the time when the signal Υ (ϋ) exceeds the zero level.

Impulses And _o come to the control input of the electronic key 20. When

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the absence of pulses, the electronic key 20 is closed and the voltage at its output is zero. During the action _{of the} pulse and the electronic key 20 is opened and the signal output from the second scaling amplifier 19 equal to «Υ _ο (k - a second gain scaling amplifier 19) is fed to a first input of the second summing amplifier 21. Thus, in the absence _of pulses and the signal Y (s) = X (e), with the appearance of pulses And _o , (£) = X (s) + kU ₀ . The beginning of the pulse And _o corresponds to the moment _when the input signal exceeds the zero level, since Y (s) = X (s). The end of the pulse And _o corresponds to the moment of time when Υ (ϋ) = (ϋ) + κΥ ₀ 0, or X (s) <- kU _about .

If the signal from the vibration transducer 1 is periodic, the signal at the output of the sampling and memory circuit 8 will be constant (for example, for a sinusoidal signal X (s) =

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scheme 8 sample and memorization will be proportional to T _about ). At the output of the second differentiating element 9, the signal will be zero. Therefore, at the first input of the summing amplifier 13, the signal will be zero, i.e. for a periodic output signal summed-. amplifier 13 depends only on the average value of the measured value and the rate of increase of the average value.

If the signal from the vibration transducer 1 is random, then the signal at the output of the sampling and memorizing circuit 8 will change randomly, in proportion to the current value of the time when the signal exceeds the zero level.

The random signal from the output of the sampling and memorizing circuit 8 after the second differentiating element 9 is rectified in the second rectifier Yu and through the third integrator 11 and the scaling amplifier 12 the average value of the derivative of this signal goes to the first input of the summing amplifier 13.

The output signal from the summing amplifier 13 through the threshold element 14 includes an actuator 15, which serves to signal

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warnings about a dangerous change in the nature or level of vibration, or to turn off a controlled machine.

Consider the case where the signal from the vibration transducer 1 is the sum of the periodic and random components.

The moment of appearance of pulses And _s is determined as in the prototype by the moment when the vibration signal exceeds the zero level, however, the moment of the end of the pulses And _о depends on the average value of the vibration signal and on the gain factor of the second scaling amplifier 19 selected in advance. noise, to which the random component of the signal will not lead to multiple triggering of the limiter, since the trigger threshold when no sign of a signal from plus to minus differs from the trigger threshold when changing the sign of the signal from minus to plus by the value - κΥ _ο , is proportional to the average value of the vibration signal and as a result of this (due to the small level of the random component) the power of the periodic component.

Thus, at a small level (determined by the K coefficient) of the random component of the signal, the pulse duration will be proportional to the time it takes to exceed the zero level of the periodic component of the signal and change slightly around this value. The signal at the output of the second differentiator 9 will be proportional to the rate of change of the pulse duration.

Claims (1)

Claim A device for controlling vibration, according to the author. No. 1420384, characterized in that, in order to improve noise immunity, it is equipped with series-connected second scaling amplifier, the input of which is connected to the output of the first integrator, an electronic key, the control input of which is connected to the output of the limiter, and the second summing amplifier, the second input of which is connected to the output of the amplifier, and the output to the input of the limiter.