SU1228139A1 - Teaching-aid device on engineering geodesy - Google Patents

Abstract

The invention allows to extend the functionality of a training device for engineering geodesy. In the device, synchronizer 1, filter-mixer 2, power source 3, separation filter 4, trigger 5, delay unit 6, generator 7 of probe pulses, amplifier-limiter 8, time meter 9, the second input of which is connected to the first output of the trigger 5 are connected in series , block 10 OR with a trunk amplifier, a single-channel input of which is connected to the second output of trigger 5, a trunk amplifier 11, block 12 of a survey, the first single-channel input of which is connected to the output of synchronizer 1 through a driver 13, the input of which It is connected to the second single-channel input of the polling unit 12 and to the output of the selekdia unit 14 of the start measurement code, the output of which is connected to the output of the amplifier 11. The output of the unit 12 is connected to the arithmetic unit 15 with an indicator, which is a terminal unit. Two acoustic transducers 16 and 17 are installed at the ends of the upper vessels 18 connected by pipe 19, partially filled with liquid 20. Transducers 16 and 17 are connected to the corresponding inputs of the switch 21, the first single-channel input of which is connected to the second output of the trigger 5, and the second from generator output 7 probe pulses. 1 il. about with

Description

one

The invention relates to educational devices and can be used in teaching geodesy.

The aim of the invention is to expand the functionality of the device.

The drawing shows a block diagram of the device.

The device consists of series-connected synchronizer 1, filter-mixer 2, power supply 3, separation filter 4, trigger 5, delay unit 6, probe pulse generator 7, limiting amplifier 8, time meter 9, the second input of which is connected to the first trigger output 5, block OR 10 with a trunk amplifier; a single-channel input of which is connected to the second output of trigger 5, a trunk amplifier 11, polling unit 12, the first single-channel input of which is connected to the code of the synchronizer 1 through atel 13 whose input is coupled to a second single-input unit 12 nokanalnym survey and selection output unit 14 measurement start code having an input connected to the output of the main amplifier 11.

An arithmetic unit 15 is connected to the output of the polling unit 12 with an indicator, which is the terminal unit of the device. In addition, the device is equipped with at least two acoustic transducers 16 and 17, which are installed at the ends, for example, upper vessels 18, interconnected by a pipeline 19, partially filled with liquid 20, with acoustic transducers 16 and 17 connected to the corresponding inputs of the switch 21, the first single-channel input of which is connected to the second output of the trigger 5, and the second to the output of the generator 7 probe pulses.

The device works as follows.

Before demonstration of measurements, vessels 18 connected by pipeline 19 are filled with liquid 20 and installed on the object under test: if leveling is performed, then one of the vessels 18 is placed on a repro: if the deflection of the structure is determined, then the vessels 18 are placed with a given step along a flexible element 39 2

cop. Fluid 20 through conduit 1 is distributed in vessels 18 according to the law of communicating vessels. When the device is turned on, the voltage from the power source 3 is supplied to the main blocks, including through the filter-mixer 2, the coaxial cable and the separation filter 4, to the power buses of the blocks 5-10, 21. In the arithmetic unit 15, the corresponding program of numerical processing is entered results.

The synchronizer 1 produces short periodically following pulses that are fed through the mixer 2, the coaxial cable and the splitter 4, to the counting input of the trigger 5, causing a change in its state each time. The positive potential (the choice of polarity is only for the sake of description) appearing at the second output of the trigger 5 causes a change in the counter state of the switch 21, as a result of which the acoustic transducer 16 and 17 are connected to the input of the generator 7 of the probe pulses (in practice acoustic transducers can be much larger), the number of which is determined by the output code of the counter of the -1 switch 21. With the arrival of the next sync pulse, trigger 5 changes its state and a positive potential appears on it first output. In this case, the time meter 9 is converted to. measurement mode: information is reset in its built-in counter, after which time counting begins. After the time interval required to transfer the time meter 9 to the measurement mode, the output of the delay unit 6 also has a pulse, which initiates the probe pulse generator 7. The output pulse of the generator 7 is excited by the acoustic transducer 16 and 17 (or another device). contains a greater number of acoustic transducers), which was connected to the switch 21 in the pre-cycle cycle. The acoustic transducer 16 (17) sprinkles an ultrasonic impulse in the direction of the surface of the liquid 20, which is reflected from its surface and again converted into an electrical signal through the switch 21 to the input force

the limiting body 8. At the output of the limiting amplifier 8, a pulse is produced, the leading edge of which coincides in time with the moment of registration of the echo pulse. This impulse stops the time counting process in the meter 9, a number is stored in its counter, which is equal to the propagation time of the ultrasonic signal from the moment of its sending until the registration of the echo pulse.

Since the velocity of propagation of ultrasound in air is known, the distance from the surface of the acoustic transducer to the surface of the liquid can be calculated from the measured time. For this purpose, other device blocks are used, which work as follows.

The inputs of the block OR S are connected to the outputs of the counters of the switch 21 and the meter 9-time. If the output of the trigger 5 is positive. potential, then the output of the block OR 10 is the output code (connected acoustic transducer numbers) of the built-in counter of the switch 21, amplified by an internal trunk amplifier. Otherwise, the output of the block 10 is the result code of the time measurement of the built-in counter of the meter 9 times. The output potentials of an OR 10 unit with a trunk amplifier are transmitted via a multi-core low-frequency cable to the input of a trunk amplifier 11. The need to introduce these main amplifiers is due to the fact that in case of a device being demonstrated in large auditoriums, the distance between the control zone and the complex itself can be measured by tens of meters . In this case, it becomes necessary to match the output impedance of the block OR 10 and the input impedance of the blocks with the characteristic impedance of the low frequency cable.

Structurally, the vessels 18 are designed in such a way that there is always an air gap between the working surface of the acoustic transducer 16 (17) and the surface of the liquid 20, and therefore the result of time measurement is always different from zero. The state of the built-in counter of the switch 21 can be equal to 00 ... .. O in the initial measurement cycle

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neither Code 00 ... O is allocated by block 14 of the selection code for the start of measurements, which generates a pulse of setting the initial state of block 12 of the poll and the former 13 only when the code is received. Code 00 ... O appears every time after interrogation of all acoustic transducers 16 (17 and others, if provided by the device).

By setting the initial state, the shaper 13 generates a control for the signals arriving at the polling input 12 only when even pulses arrive at its input from the synchronizer 1. At the input of the polling unit 12, a time measurement result code arriving from the main amplifier 11. The polling unit 12 successively enters into the corresponding registers of the arithmetic unit 15 the numerical values of the time measurement results, and then automatically generates an arithmetic unit translation command and 15 to compute mode. The result of the calculation is displayed on the indicator of block 15. When odd pulses arrive at the input of the imager 13 from the synchronizer output 1, the start pulse of the polling unit 12 does not stop. This state coincides with the time interval when the connected number code goes to the multi-channel input of the imager 13 acoustic transducer 16 (17). This code is used to switch the register counter of the polling unit 12. For this, not a pulsed, but a potential control performed by the output of the former 13 is used. Structurally, this is ensured by the inclusion of a symmetric trigger switched by the pulses of the synchronizer 1 and set in the initial state by the output impulse of the measurement code selection unit 14, into the structure of the former 13.

The above operations are repeated until the end of their interrogation cycle of all acoustic transducers 16 (17). At the time when the last measurement result was entered into the arithmetic unit 15, the program for the final calculations was entered programmatically, during which it was determined

The required elevation values are. The measurement cycle is then repeated in the sequence indicated.

When using the invention, the efficiency of measurements at a number of control points (at least two) is enhanced, which expands the functionality of the device: a training device allows you to demonstrate the measurement of structural deflections if the number of control points (vessels) is more than three. The proposed set of blocks and circuits and their connections allow demonstration of the training device in systems with remote control, in addition, the proposed solution removes restrictions on the number of connected sensor vessels.

Claims (1)

Invention Formula A training instrument for engineering geodesy, containing communicating vessels with fluid, connected by a pipeline, at the end of which acoustic transducers, a synchronizer, a trigger, a generator of probe pulses are installed, connected via an amplifier-limiter to the first time meter input, polling unit, output connected to the input of the arithmetic unit, and the driver, the first input associated Editor N.Shvyschka Compiled by V. Yermakov Tehred M. Khodanich Proofreader G. Reshetnik Order 2290/51 Circulation 455 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 396 with the first input of the polling unit, t - characterized by the fact that, in order to expand the functionality, a selection block, a trunk amplifier, an OR logic unit, a switch, a delay unit, a separation filter, a mixer filter and a power supply, an output associated with the first input of the mixer filter, the second input of which is associated with the synchronizer output and with the second driver input, the output connected with the second input of the polling unit, the first input connected with the output of the selection unit whose input is connected to the third ode polling unit and through the trunk amplifier - with the first output of the logic block OR, the second output connected to the second input of the time meter, the third input of which is connected to the first output of the trigger and through the delay unit and the generator of probe pulses - to the first input of the switch, the second input of which connected to the first input of the logical block OR, and to the second output of the trigger, which is connected via a decoupling filter to the output of the mixer-filter, the second input of the logical block OR connected to the output of the switch The third input is connected to acoustic transducers.