RU1798629C - Digital period meter for vibrating wire transducer - Google Patents

Abstract

Usage: the device analyzes the state of the line connecting the string sensor to the periodometer and indicates the closure and breakage of the line. Essence: depending on the condition of the connecting line, the shape of the voltage pulse exciting the string sensor changes. The change in the shape of the voltage pulse is analyzed using a differentiator, two shaping devices, a second OR circuit, and a second counter. The results of the analysis are displayed on the indicator. 2 ill.

Description

The device relates to electrical engineering and can be used in hydraulic engineering to monitor the condition of structures with string sensors.

An object of the invention is to expand the functionality of a device.

In FIG. 1 shows a block diagram of a device, FIG. 2 - diagrams explaining his work.

The digital periodometer for string sensors contains a series-connecting voltage source 1, a charge resistor 2, a key 4, a pulse amplitude limiter 8 and a driver amplifier 9, a storage capacitor 3 connected between the output of the charge resistor 2 and a common bus, while the string sensor connected to the output of the key 4, the first 10 and second 11 frequency dividers, the counting inputs of which are connected to the outputs of the amplifier-former 9. the first 15 and second 16 of the circuit And, the first inputs of which are connected respectively to the outputs of the first 10 and second 11 frequency dividers,

the first circuit OR 19, the first and second inputs of which are connected to the outputs of the first 15 and second 16 circuits AND, connected in series with the output of the first circuit OR 19, the first counter 20 and indicator 21, connected in series with the crystal oscillator 17 and the first forming device 18, the first and second the outputs of which are connected to the second inputs of the first 15 and second 16 circuits AND, the circuit ILI-NOT 13, the first and second inputs of which are connected to the outputs of the first 10 and second 11 frequency dividers, the first delay line 12 and trigger 14, the counting input and output of which RESET which soy respectively, with the outputs of the OR-NOT 13 circuit and the first delay line 12, and the output with the RESET inputs of the first 10 of the second 11 frequency dividers, serially connected to a clock generator 5, a second delay line 6 and a one-shot 7, the output of which is connected to the control the key input 4, the output of the clock 5 is connected to the RESET input of the first counter 20, the output of the second delay line 6 is connected to the input of the first

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delay lines 12, as well as a differentiating circuit 22, the input of which is connected to the output of the key 4 and the sensor, the second 23 and third 24 forming devices. the inputs of which are connected to the output of the differentiating circuit 22, the second IL-25 circuit and the second counter 2B are connected in series, the inputs of the second OR-25 circuit being connected to the outputs of the second 23 and third. 24 forming devices, the first and second outputs of the second counter 26 with the second and third inputs of the indicator 21, the RESET input of the second counter 26 with the generator 5 clock pulses.

The device operates as follows.

The storage capacitor 3 is charged from the voltage source 1 through the charging resistor 2. The pulse from the clock generator 5 (Fig. 2a) resets the first 20 and second 26 counters and starts the single-vibrator 7 through the second delay line b (Fig. 2). 2b), which opens the key 4 and the pulse from the storage capacitor 3 (Fig. 2c) is fed to the string sensor, exciting damped harmonic oscillations in it, which are transmitted through the pulse amplitude limiter 8 (Fig. 2d) to amplifier-shaper input 9. Delay time on the second line after holders b are necessary to prepare the second counter 26 for operation before the passage of the voltage pulse from the output of the switch 4 to the sensor and the input of the differential circuit 22. The pulse duration of the one-shot 7 (Fig. 2, 6} is selected so that during its operation the storage capacitor 3 is completely discharged through the key 4 and the excitation coil of the string sensor. The pulse amplitude limiter 8 is necessary so as not to pass a high-voltage sensor excitation pulse to the input of the imaging amplifier 9. The limiting voltage is selected no more than that acceptable for the input of the driver amplifier 9. The driver amplifier 9 generates two sequences of pulses associated with the positive and negative half-waves of the input signal (Fig. 2e, f). The frequency dividers 10 and 11 after resetting the trigger 14 by the pulse N through per-. two delay intervals NT, where T is the oscillation period of the input signal, N is the division coefficient of the dividers 11 and 10. These time intervals (Fig. 2, a, and) arrive at the inputs of circuits And 15 and 16, to the second inputs of which

pulse sequences fo / 2, shifted relative to each other by half the period, formed by the forming device 18 from pulses of the crystal oscillator 17 with a frequency of 1C. The first delay line 12 delays the reset of the trigger 14 and the start of counting of the frequency dividers 10 and 11 during the transient oscillations of the sensor string caused by the high voltage voltage pulse. The pulses from the outputs of the circuits And 15 and And 16 through the circuit OR 19 (Fig. 2. l) are fed to the input of the first counter 20, in which at the end of the count a number equal to N -Т f0 is recorded.

displayed by a digital indicator 21. After the end of the generated pulses at the outputs of the frequency dividers 10 and 11 of the OR-NOT 13 circuit produces a positive voltage drop, which

cocks the trigger 14 and resets the frequency dividers 10 and 11. The process is repeated after the next pulse of the clock generator 5.

If the connecting line is

in reference operating state, the storage capacitor 3 is completely discharged through the excitation coil of the string sensor (Fig. 2c 1) during the duration of the pulse of a single-vibrator 7 (Fig. 2b). Wherein

at the output of the differentiating circuit 22, a positive pulse corresponding to the pulse front of FIG. 2c, from which the second forming device 23 will generate a pulse transmitted through the second OR circuit 25 to the counting input of the second counter 26. The counter 26 is a binary counter with a counting module and with decoding of the output state (see A. Lantsev. etc. Digital devices

on complementary TIR integrated circuits. - M .: Radio and communications, 1983. - p. 57), while the signal at the output O (Fig. 2H, the first output) is set when the front of the clock pulse arrives at the RESET input (Fig. 2a). Upon receipt of the second counter 26 of the first counting pulse at the counting input from the output of the OR circuit 25 (Fig. 2, m), a signal appears at the output 1, and after the second counting pulse, at the output 2 (the second output of the counter 26). Thus, in the normal state of the connecting line, one pulse passes to the counting input of the counter 26 and the signal is installed at the 1st output, and at the first (O) and

second (2) outputs no signal.

When the connecting line is shorted, the input of the differentiating circuit is shorted, so at the first output of the second counter 26 the signal set at the reset will remain, and the presence of a short circuit of the line will be displayed on the indicator 21,

When the connecting line is broken, the storage capacitor 3 during the deactivation of the pulse of the one-shot 7 only partially discharges through the large input resistance of the voltage pulse limiter 8. After the end of the pulse, a sharp voltage drop forms at the input of the differentiating circuit 22 (Figs. 2 and 3 ), as a result of which a positive pulse corresponding to the front and a negative pulse corresponding to the decay of the pulse appear at the output of the differentiating circuit 22. The forming devices 23 and 24 generate two counting pulses corresponding to positive and negative pulses at the output of the differentiating circuit 22. After the first counting pulse supplied to the counting input of the second counter 26 through the OR circuit 25, the signal at the first output of the counter 26 disappears, and after the second counting pulse, the signal appears at the second output of the counter 26, as a result of which a break in the connecting line is displayed on the indicator 21.

From the above it follows that the proposed device allows you to analyze the state of the line connecting the string sensors to the device and display this status on the indicator, as a result of which the functionality is expanded. When constructing automated data collection systems, the proposed device makes it possible to record the passage of false information / associated with violations of the communication line between string sensors and a periodometer to storage devices, which increases the reliability of the information.

Formula A digital periodometer for string sensors containing a voltage source, a first driver, first and second dividers, the inputs of which are connected to the output of the first driver, the first and second circuits And, the first inputs of which are

are connected respectively to the outputs of the first and second dividers, the pulse generator and the second driver connected in series, the outputs of which are connected to the second inputs of the first and second AND circuits, the first OR circuit and the first counter connected in series, the first and second inputs of the OR circuit are connected respectively to the outputs of the first and the second circuit And, characterized in that, in order to expand the functionality by providing along with measuring the periods of oscillation and determining the state of the connection lines of the string sensor, it is equipped with a series-connected charging resistor, a key and a pulse amplitude limiter, the input of the charging resistor is connected to the output of the voltage source, the output of the pulse amplitude limiter is connected to the input of the first driver, a storage capacitor connected between the output of the charging resistor and a common bus connected in series by a clock generator, a first delay line and a single vibrator, the output of which is connected to the second key input, connected in series the second delay line and the trigger, the OR-NOT circuit, the output of which is connected to the second input of the trigger, and the first and second inputs are the outputs of the first and second dividers, the input of the second delay line is connected to the output of the first delay line, the output of the trigger is connected to the common input of the first and the second dividers connected in series by the differentiating circuit, the third driver, the second And circuit, the second counter and indicator, the fourth driver, whose input is connected to the output of the differentiating circuit, and the output to the second input of the WTO second AND gate, the output clock generator is connected to the second inputs of the first and second counters, the indicator connected to the output of the first counter output for connection to a string encoder, the input of the differentiating circuit is intended for connection to the sensor output string.