RU5248U1 - DEVICE FOR MEASURING PHYSICAL QUANTITY - Google Patents

Abstract

1. A device for measuring a physical quantity, including a computer, a sensing element, an alternating voltage generator connected to it, comprising frequency-sensing elements, characterized in that the generator further comprises a voltage level converter, the output of which is the output of the generator, the computer configuration complies with the Multimedia Personal Computer specification , the output of the driver is connected to the input of the audio adapter of such a computer, the elements of the driver have parameters, providing matching the information-significant components of the frequency spectrum of its output voltage with the input parameters of the computer audio adapter in the entire measurement range of the physical quantity. 2. The device according to claim 1, characterized in that the voltage level converter is made in the form of optoelectronic, coordinated transmitter and receiver. The device according to claim 1, characterized in that the voltage level converter is made in the form of a transformer. The device according to claim 1, characterized in that it further comprises an identifier of the sensitive element and the driver connected to the digital input of the computer. The device according to claim 1, characterized in that it further comprises a driver control unit, wherein the input of the unit is connected to the digital output of the computer or its audio adapter, and the output of the unit is connected to the control input of the driver.

Description

The invention relates to measuring equipment using a computer when receiving and working with metrological information for general purposes. Known measurement devices using a computer, the basis of which is the conversion of a physical quantity into electrical voltage, where the information is contained in the signal level C1,2. A device with the conversion of a physical quantity into a voltage of a fixed level is known, and information about the measured quantity is contained in the frequency (period) of the SZ voltage.

Closest to the proposed technical essence and the achieved result, and adopted by the authors as a prototype, is a device for measuring physical quantity 4, in which a signal is generated with a duration proportional to the measured value. To do this, use the charge of the reference capacitor to a certain voltage level, through a resistor whose electrical resistance is sensitive to the measured value.

The device consists of a thermistor connected in series with a capacitor, and a transistor connected in parallel with the capacitor. These elements form an oscillatory circuit, and the parameters of the elements determine the frequency of the output voltage. The listed elements and Schmitt trigger form a pulse voltage generator. The output of the driver is connected to the digital input of the computer. The device operates as follows. At the signal of the computer, the transistor is locked, and at the same moment, the computer starts the internal time counter. The capacitor, through the thermistor included in its charge circuit, is charged to the value of the Schmitt trigger tipping threshold. The moment of charge of the capacitor is recorded. The voltage drop signal from the output of the Schmitt trigger enters the computer, stopping the internal counter, and by the computer signal puts the transistor in saturation mode. The discharge of the capacitor occurs through the internal resistance of the transistor. Information about the measured value is contained in the internal computer counter.

The prototype allows you to measure the physical quantity, temperature, to compensate for the effect of temperature instability of the characteristics of some components of the device implementing it on the measurement results.

Significant disadvantages of the known device are limited functionality that does not allow measurements using common personal computers without additional devices and driver programs.

The basis of the invention is the task of expanding the functionality of the device, as well as simplifying the measurement procedure by unifying the technical means used.

Additionally, the following tasks are set:

-increase the reliability of measurements;

- providing electrical isolation, up to remote.

wireless, communication between the components of the measuring system. - control of the shaper, to increase the resolution of the measurements.

The main task of measuring a physical quantity using a computer is solved by a device including a computer, a sensing element, an alternating voltage generator connected to it, containing frequency-setting elements, according to the invention, the generator further comprises a voltage level converter, the output of which is the output of the generator, the computer configuration corresponds to the specification Multimedia Personal Computer (MPS), the output of the driver is connected to the input of the audio adapter of a computer, the elements of the shaper have parameters that ensure that for the informationally significant components of the frequency spectrum of its output voltage, compliance with the input parameters of the computer’s audio adapter over the entire measurement range of the physical quantity.

The best result is achieved in the device according to the invention in that the voltage level converter is made either in the form of optoelectronic, matched to one another, transmitter and receiver, or in the form of a transformer.

Additional tasks are solved by the fact that according to the invention, the device contains an identifier of the sensitive element and the driver connected to the digital input of the computer, as well as the fact that it is equipped with a driver control unit, the input of the unit is connected to the digital output of the computer or the computer’s audio adapter, and the output of the block is connected to the input shaper control.

The invention is illustrated by drawings:

Figure 1 shows a functional diagram of a device for measuring a non-singular physical quantity.

Figure 2 shows an example implementation - a schematic diagram of a device for measuring temperature.

On Fig. 3 shows a functional diagram of a device containing the identifier of the sensing element and the shaper. Figure 4 shows a functional diagram of a device containing a control unit of the shaper.

Functional diagram of the device is shown in FIG. 1. The device contains a sensing element 1, an alternating voltage generator E connected to it, comprising frequency-setting elements 3, with parameters providing for the information-significant components of the frequency spectrum of its output voltage the frequency and its changes within the limits satisfying the parameters of the output connected the level 4 converter of the input of the audio adapter 5 of computer 6. Computer b, equipped with software, has a configuration that complies with the Multimedia Personal Computer specification. The level 4 converter can be made in the form of coordinated, optical, transmitter and receiver information, as well as in the form of a matching transformer or radio transceiver.

The device operates as follows. The measured value acts on the sensitive element 1 and leads to a change in its electrical parameter, as a result of which the parameter of electric oscillations in the shaper 2 of an alternating electric voltage and, accordingly, its frequency are changed / /// K /

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driving voltage. The latter, from the output of the level 4 converter, is fed to the input of the audio adapter 5 of computer b, the configuration of which complies with the Multimedia Personal Computer specification, is processed, and, using software and information about the transfer characteristics of the driver and the parameters of the frequency-setting elements stored in the computer’s memory, it is possible to determine value of the measured value.

In FIG. 2 shows a schematic diagram - an example implementation of a device for measuring temperature. The device contains a sensing element (thermistor) 1 connected to the output 7 of the amplifier 8 of the generator 2 of an alternating electric voltage, and, through an adjustment resistor 9, with a measuring capacitor 10, a tuning capacitor 11 and an inverting input 12 of the amplifier 8. The output 7 of the amplifier 8 is connected to the resistors 13, 14 and 15 of the converter 4 of the voltage level of the driver and, through a resistor 13 with a non-inverting input 16 of the amplifier 8. Through a resistor 15, a non-inverting input 16 is connected to analog ground, and through a resistor 14 to the input audio adapter 5 of computer 6 of the MPS specification equipped with software. The inverting input 12 of the amplifier 8 through the capacitor 10 and the trim capacitor 12 is connected to the analog ground. The device operates as follows. The initial state of the circuit is determined by the absence of charge on the capacitor 10 and, as a result, by almost zero voltage at the inverting input 12 of the amplifier 8. At the same time, part of the output voltage of the amplifier 8, through the resistors 13, 15 of the converter 4 of the voltage level of the driver, is supplied to

non-inverting input 16 of the amplifier 8 and exceeds the voltage at the inverting input 12. As a result, the voltage at the output 7 of the amplifier 8 has a positive polarity and a value determined by the supply voltage and the internal circuit of the amplifier. The capacitors 10 and 11 begin to be charged by the current flowing from the output 7 of the amplifier 8 through the sensing element 1 and the adjustment resistor 9 to the analog ground. A charge will begin to build up on the capacitor plates. As the capacitor charges, the voltage drop across it (modulo) will increase until it exceeds the voltage at the non-inverting input 16. Then the output voltage of the amplifier 8 will change to the opposite, and the process will be repeated. Thus, the frequency of the fundamental harmonic of the output voltage is determined by the time constant, numerically equal to the product of the sum of the resistance values of the sensing element 1 and the regulation resistor 9 by the total capacitance of the measuring 10 and tuning 11 capacitors, which allows us to uniquely relate the frequency of the fundamental to the measured value. A change in the measured temperature leads to a change in the resistance of the sensing element 1, i.e. charge time and, accordingly, the fundamental frequency of the output alternating electric voltage supplied to the input of the audio adapter 5 of the computer of the MPS specification. A computer equipped with software calculates the measured value. By changing the value of the adjustment resistor 9 and the tuning capacitor 11, it is provided, for a particular type of sensor 1 and a selected temperature measurement range, the main generation frequency in the range corresponding to the input parameters of the audio adapter 5

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computer b. Resistors 13, 14, 15 oOeoperate the correspondence to the input parameters of the audio adapter according to the level of voltage of the driver 2 supplied to its input.

In an example of the implementation of the proposed measurement device, a shaper circuit operating in a self-oscillating mode (multivibrator, generator, etc.) is selected, one of the frequency-setting elements of which is a sensitive element. A sensitive element subjected to physical influence changes its electrical parameter. Since the sensitive element is involved in the formation of electrical self-oscillations, this will lead to a change in their parameter (frequency), and, accordingly, the frequency of the output voltage of the driver. With the selected multivibrator scheme, the signal at its output contains a large number of harmonics, but the main, first harmonic is information-significant. Therefore, the parameters of the frequency-setting elements must be such that in the entire measurement range of the physical quantity, the main harmonic of the frequency spectrum of the output voltage is consistent with the input parameters of the computer audio adapter, the configuration of which complies with the Multimedia Personal Computer specification. For some measurements, the second and subsequent harmonics, or just them, may be information-significant. When using resistive sensors (thermistor, photoresistor, strain gauge) it is very convenient to use a shaper made according to the multivibrator scheme. With capacitive sensors (temperature, size and other values) and sensors using the capacitive effect (force, displacement, pressure, etc.), a high-frequency capacitive generator circuit is convenient as a shaper, and the output voltage of the circuit with the required parameters is formed by mixing voltages with measuring and reference generator. For parametric sensors (photodiode, thermocouple, etc.), a voltage-controlled oscillator (VCO) circuit is preferred as a shaper. The above discussion of informationally significant components is valid regardless of the choice of a specific implementation scheme of the VCO. For non-contacting Hall sensors, the circuit implementation of the shaper will be very difficult. In particular, it is necessary to stabilize the output current of the circuit circuit into which the sensor is included. The calculation of the physical quantity, as well as in the prototype, is done by a computer. The signal entered into the computer is subjected to Fourier transform, the information-significant components of the frequency spectrum of the signal and the computer are extracted, using the transfer characteristics of the sensing element, shaper, computer audio adapter, calculates the value of the physical quantity programmatically.

An example implementation illustrates the simplicity of the circuitry used. This makes it possible to manufacture, up to serial, sensor modules with a former. The presence of a number of such modules sets the task of identifying them with the aim of faultlessly connecting them and, accordingly, increasing the reliability of measurements in general. The sensing element and driver module, equipped with an identifier, in turn, provides simplification of the procedure and unification of measuring instruments.

On Fig. 3 shows a functional diagram of a device containing the identifier of the sensing element and the shaper. The device, in addition to the above, contains an identifier 17, which is an autonomous unit of non-volatile read-only memory, the output of which is connected to the digital input of the computer b. The identifier contains identification information about the type of sensor and shaper, the kind and range of measurement of the physical quantity, the calibration of the sensitive element and the shaper.

The device operates as follows. The measured value affects the sensitive element 1, which leads to a change in its parameter. As a result, the parameter of electrical vibrations in the shaper 2 of an alternating electric voltage and, accordingly, the parameter of its output voltage are changed. The latter, from the output of the level 4 converter, is fed to the input of the audio adapter 5 of computer b, the configuration of which corresponds to the Multimedia Personal Computer specification, is processed, and, using software and information on the transfer characteristics of the driver and the parameters of the frequency-sensing elements read from identifier 17, allows to determine value of the measured value.

The task of controlling the shaper, in order to increase the resolution or expand the measurement range, is solved by a device containing a control unit of the shaper.

Figure 4 shows a functional diagram of such a device. The device, in addition to the above, contains a control unit 18 of the driver 2 connected to the digital output of the audio adapter 5 or the digital output of the computer b.

- 9 The device operates as follows. When the device is initialized, computer 6, depending on the required measurement range, sets, through the control unit of the former 18, the transfer characteristics of the former and the parameters of its elements. The measured value affects the sensitive element 1, which leads to a change in its parameter. As a result of this, the electric oscillation parameter in the shaper 2 of the alternating electric voltage and, accordingly, its output voltage are changed. The latter, from the output of the level 4 converter, is fed to the input of the audio adapter 5 of computer 6, the configuration of which corresponds to the Multimedia Personal Computer specification, is processed, and, using software and information about the given transfer characteristics of the driver and the parameters of its frequency-setting elements, allows you to determine the value of the measured value .

Thus, due to the difference in the composition and structure of the device and its parts, their connection, as well as the parameters of the elements, the claimed technical solution is characterized by new properties:

- provides the ability to select the optimal ratio of accuracy, range and duration of the measurement of a physical quantity, as well as to measure a number of physical quantities, including simultaneously, using one computer, thanks to more preferable for measurement purposes, information-relevant parameters of the generated voltage and, accordingly terms of its agreement with the input parameters of the computer;

- significantly simplifies the measurement procedure for the user and standardizes it through the use of a unified technical tool that completes this procedure - a computer of the widespread MPS specification;

- expands functionality by using both frequency and the level of generated voltage as information-relevant parameters, simplifies and unifies the measurement procedure, thanks to a new connection with the input of the computer’s audio adapter;

- expands functionality by performing a level converter in the form of one or another means of electrical isolation.

Additionally, it simplifies, unifies and automates the measurement procedure, and increases their reliability due to the presence of the identifier of the sensitive element and the driver, as well as the presence of the driver control unit.

11 Sources of information:

1. Japan application. 5-25409, G01D 9/00

2. PCT application (WO). 94/12940, G06F 15/20

3. Pairing sensors and input devices with computers IBM PC./ Ed. Ulompkins and J. Webster.- M .; World, 1992 p. 312.

4. France application. 2697080, ШУ 3/02 (prototype)

Claims (5)

1. A device for measuring a physical quantity, including a computer, a sensing element, an alternating voltage generator connected to it, comprising frequency-sensing elements, characterized in that the generator further comprises a voltage level converter, the output of which is the output of the generator, the computer configuration complies with the Multimedia Personal Computer specification , the output of the driver is connected to the input of the audio adapter of such a computer, the elements of the driver have parameters, providing matching the informationally significant components of the frequency spectrum of its output voltage with the input parameters of the computer audio adapter in the entire measurement range of the physical quantity.  2. The device according to claim 1, characterized in that the voltage level Converter is made in the form of optoelectronic, coordinated between a transmitter and a receiver.  3. The device according to claim 1, characterized in that the voltage level Converter is made in the form of a transformer.  4. The device according to claim 1, characterized in that it further comprises an identifier of the sensing element and the driver connected to the digital input of the computer.  5. The device according to claim 1, characterized in that it further comprises a driver control unit, wherein the input of the unit is connected to the digital output of the computer or its audio adapter, and the output of the unit is connected to the control input of the driver.