SU1255872A1 - Vibration-type measuring device - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure vibration accelerations with a considerable length of the connecting line between the sensor AND the electronic unit of the device. The purpose of the invention is to increase accuracy with a considerable length of the connecting line due to the possibility of operatively checking the operability of the device. During operation of the device, along with information signals coming from the electroacoustic converter, through the gain channel to the recorder, control signals from the driver output of the control electric signal are simultaneously sent to the latter through a step attenuator and a communication transformer. 1 il. with

Description

i

The invention relates to a measurement technique and can be used to measure vibration accelerations with a considerable length of the connecting line between the sensor and the electronic unit of the device.

The purpose of the invention is to improve the accuracy with a considerable length of the connecting line due to the possibility of operatively checking the operability of the device.

The drawing shows the ma vibro-measuring device.

The device contains a series-connected electroacoustic converter 1, a connecting line 2, a pre-amplifier 3, a low-pass filter 4, a main amplifier 5 and a recorder 6, and a transformer 7, the primary winding of which is included in one of the wires of the connecting line 2, and the secondary winding the output is connected to the bus 8 of zero potential, connected in series to the driver 9 of the control electric signal, the first stepped attenuator 10 and the switch 11, the output of which is connected to the second A output of the secondary winding of the transformer 7, the capacitor 12 and the second stu- penchatEUsh attenuator 13 connected in a feedback circuit between the input - and output, respectively, of the preamplifier 3 and the main amplifier 5, sliders 14, u 15 of the first

10 and second 13 step attenuators are mechanically interconnected

and the second input 16 of the switch 11 is designated to provide control commands thereto.

Vibration measuring device operates as follows.

In the initial state, the connection of the first step attenuator 10 with the secondary winding of the transformer 7 is broken. Information signals from the electroacoustic converter 1 are fed through connecting line 2, preamplifier 3, low-pass filter 4, main transmitter 5 to recorder 6. Periodically, the device is checked for correct operation of the device and the correct setting of the electronic part of the device. 16 switches

11 give control signal, in re722

As a result, the connection of the first step attenuator 10 with the secondary winding of the transformer is closed. 7. Electrical control signals

From the output of the imaging unit 9, the control signals are transmitted through the first stage attenuator 10 and the switch 11 to the transformer 7, are transformed into its primary winding and

arrive at the input of preamplifier 3 and then through the low pass filter. 4 and the main amplifier 5 is fed to the recorder 5. The recorded signal is

co} troll for device performance.

The frequency of the electrical signal, i.e., imitating the output signal of the electroacoustic converter 1, is selected based on the cut-off frequency of the low-pass filter 4 f. and is

 k. And sr.

For all other frequency subbands of the equipment, complete with replaceable low-pass filters, the cut-off frequency of the filters exceeds the cut-off frequency of the low-pass filter. Therefore, the electrical co-control signal is in the passband of the equipment and arrives at the recorder with minimal dynamic distortion. The amplitude of the electrical control signal for each sub-band

The measurement is selected in the working part of the amplitude characteristic of the signal conversion channel. To ensure minimal non-linear distortion, the output voltage of the electrical control signal generator of the piezoelectric sensors is set to 80% of the maximum input signal of each measurement subband.

The gain K of preamplifier 3 and the capacitance value from the capacitor 12 in the negative feedback circuit is selected from the allowable decrease in channel sensitivity S caused by the influence of the connecting line of maximum length according to

S., C (K, - 1) b.

G

D 1-L1S "XC

S

55 where Cp ,, is the dynamic input capacitance of the preamplifier 3, Cd is the capacitance of the connecting line 2 per meter of length.

31

The ability to quickly verify the operability of the vibration measuring device provides improved measurement accuracy.

Claims (1)

Invention Formula A vibration measuring device containing a series-connected electroacoustic converter, a connecting line, a preamplifier, a low-pass filter, a main amplifier and a recorder, a transformer whose primary winding is included in one of the connecting line wires, and the second winding is connected to the zero potential bus . 2558724 characterized in that, in order to increase accuracy with a significant length of the connecting line, it is equipped with a sequentially connected driver of a control electrical signal, a first step attenuator and a switch, the output of which is connected to another output of the transformer secondary winding, a capacitor and a second step attenuator, connected in the feedback circuit between the inputs and outputs, respectively, of the preamplifier and the main amplifier, the sliders of the first and second stage units enyuatorov mechanically coupled together. ten 15 I Editor B, Ivanova Compiled by G. Maksimochkin Tehred I. Veres Proofreader T. Kolb Order 4813/41 Circulation 507 Subscription .VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4