RU2537740C1 - Bridge measuring device of parameters of bipoles - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention refers to instrumentation, automation and industrial electronics. Particularly, the device enables parameter determination for four-element bipoles or sensors with four-element equivalent circuit. Bridge measuring device of parameters of bipoles includes a serial connection of generator of a complex electric feed signal, a bridge circuit and a null indicator. A bridge circuit consists of two branches. First branch is formed by serial connection of first and second resistors and first inductance coil. A serial connection of third resistor and second inductance coil is connected parallel to the first inductance coil. Fourth resistor is connected parallel to the second inductance coil. Second bridge branch is formed with serial connection of single resistor and two terminals for connection of measurement object bipoles. First bridge branch includes seven additional resistors, and element connection is modified. First and second additional resistors are connected in series with a common output of first and second primary resistors. Second additional resistor is connected to earth. A serial circuit of second resistor, first inductance coil and third additional resistor is connected in parallel to the first additional resistor. Fourth additional resistor is connected in parallel to inductance coil. A serial circuit of third resistor, second inductance coil and fifth additional resistor is connected in parallel to the fourth additional resistor. Fourth resistor and a serial connection of sixth and seventh additional resistors are connected in parallel to the second coil. Bridge circuit output forms a common output of single resistor of the second branch and first terminal of measurement object connection, and a common output of additional sixth and seventh resistors. Both outputs are connected with differential input of zero-indicator.

EFFECT: possible separate balancing of bridge circuit by adjustable resistors alone.

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Description

The invention relates to instrumentation, automation and pro-electronics. In particular, it allows you to determine the parameters of four-element two-terminal devices, the parameters of sensors with a four-element equivalent circuit or the parameters of several parametric sensors included in one bridge circuit, for example, one capacitive and two resistive sensors.

Known bridge meter parameters of multi-element passive two-terminal [Peredelsky GI, A.C. 1157467 G01R 17/10, 1985, No. 19], containing a series-connected pulse generator with voltage change over their duration according to the law of power functions, a bridge electrical circuit and a zero indicator.

Its disadvantage is the inability to balance the bridge circuit only with exemplary adjustable resistors. Exemplary adjustable resistors in manufacturing are more technologically advanced, simpler, and inexpensive compared to the manufacture of exemplary adjustable capacitors and exemplary adjustable inductive coils. They have a higher accuracy class, smaller overall dimensions and weight. They are less affected by electric and magnetic fields, as well as atmospheric conditions. All things being equal, preference is given to bridge circuits with the largest number of resistors as adjustable balancing elements, and the best option here is to balance the bridge circuits only with resistive balancing elements.

Known electric bridge [Peredelsky G.I., A.S. 998967 G01R 17/10, 1983, No. 7], comprising a trapezoidal pulse generator, a bridge circuit and a zero indicator connected in series.

Its disadvantage is the lack of separate balancing in two of the four measured parameters.

The closest in technical essence and the achieved result to the claimed device is a bridge meter of passive two-terminal parameters selected as a prototype [Peredelsky G.I., Kasyanov A.U. A.S. USSR No. 1150555 G01R 17/10, Bull. 1985, No. 14], containing a series-connected generator of sequences of supplying pulse signals with voltage variation over the duration of the pulses according to the law of power functions, a bridge electric circuit and a zero indicator.

Its disadvantage is the inability to separately balance the bridge circuit only with adjustable resistors.

The problem to which the invention is directed, is to provide the ability to separately balance the bridge circuit in several ways only adjustable resistors.

This is achieved by the fact that in a bridge meter of two-terminal parameters, it contains a supply pulse generator, which consists of pulse shapers with voltage changes over their duration according to the law k ₀ t ⁰ , k ₁ t ¹ , k ₂ t ² and k ₃ t ³ , where k ₀ , k ₁ , k ₂ and k ₃ are constant coefficients, t is the current time from the switch, from the power amplifier and synchronization unit, the output of each pulse shaper is connected to one of the inputs of the switch, its output is connected to the input of the power amplifier, the output of which forms the first output of the imp pulses relative to the ground, the output of the synchronization unit is connected to the input of each pulse shaper (synchronization input), and its output forms the second output (synchronization output) of the pulse generator relative to the ground, the common bus of the pulse generator is grounded; a bridge electrical circuit, which consists of two branches connected in parallel, the first of which includes the first and second resistors and the first inductive coil connected in series, a third resistor connected in series with the second inductive coil connected to the common terminal of the second resistor and the first inductive coil which includes the fourth resistor, the free output of the first resistor is connected to the first output of the pulse generator, the second branch of the bridge circuit includes a series connected single resistor and two terminals for connecting the two-terminal object of measurement, the free output of a single resistor is connected to the first output of the pulse generator, the common output of a single resistor and the first terminal for connecting a two-terminal object of measurement forms one of two outputs of the bridge circuit, the second terminal is grounded, the two-terminal object measurement, in particular, consists of a series-connected first resistor and a first inductive coil, in parallel which are connected in series with a single second resistor and a second inductive coil;

a null indicator, to one of the pins of the first (differential) input of which the named one of the two pins of the bridge circuit output is connected, the second output (synchronization output) of the pulse generator is connected to the second input (synchronization output), the common bus of the null indicator is grounded, seven are entered additional resistors and the inclusion of the first branch of the bridge circuit is changed, the first and second additional resistors are connected in series and introduced into the first branch of the bridge circuit, the free output of the first additional resistor and connected to the common terminal of the available first and second resistors, the free terminal of the second additional resistor is grounded, the third additional resistor is connected between the free terminal of the first available inductive coil and the common terminal of the first and second additional resistors, the fourth additional resistor is connected in parallel with the first first inductive coil, the fifth additional a resistor is connected between the common terminal of the third and fourth additional resistors and the first inductive coil, as well as the common the second inductive coil and the fourth available resistor, the sixth and seventh additional resistors are connected to each other in series, the free terminal of the sixth additional resistor is connected to the common terminal of the third and fourth available resistors, and the second inductive coil, the free terminal of the seventh additional resistor is connected to the common terminal the existing fourth resistor and fifth additional resistor, as well as the second inductive coil, the common conclusion of the additional sixth and gray of the fourth resistor forms another (second) output terminal of the bridge circuit, this output is connected to the second output of the first (differential) input of the null indicator.

The invention is illustrated in the drawing.

The bridge meter of the two-terminal parameters contains a power pulse generator 1, a bridge electrical circuit and a zero indicator. The generator consists of shapers 2, 3, 4, and 5 sequences of rectangular, ramp, quadratic, and cubic pulses and has two outputs formed by three terminals, one of which is grounded. The pulse generator also contains a switch 6 and a synchronization unit 8. The inputs of the switch are connected to the outputs of the drivers, and its output is connected to a power amplifier 7, the output of the latter is the first output of the pulse generator relative to the ground. The output of the synchronization unit is connected to the synchronization inputs of the formers, and this output is the second output of the pulse generator relative to the ground (synchronization output).

The first output of the pulse generator is connected to the input of the bridge circuit formed by the common output of two of its branches connected in parallel.

The first branch of the bridge circuit has series-connected resistors 9 (R ₉ ), 10 (R ₁₀ ) and 11 (R ₁₁ ). The free terminal of the resistor 9 is connected to the non-grounded terminal of the first output of the pulse generator, and the free terminal of the resistor 11 is grounded. In parallel to the resistor 10, a resistor 12 (R ₁₂ ), an inductive coil 14 (L ₁₄ ) and a resistor 13 (R ₁₃ ) are connected in series. In parallel to the coil 14, a resistor 15 (R ₁₅ ) is connected. Also in parallel with coil 14 are connected in series resistor 16 (R ₁₆ ), inductive coil 18 (L ₁₈ ) and resistor 17 (R ₁₇ ). In parallel to the coil 18, a resistor 19 is connected (R ₁₉ ). Also parallel to the coil 18 are connected in series resistors 20 (R ₂₀ ) and 21 (R ₂₁ ). The common output of the resistors 20 and 21 forms one of two outputs of the bridge circuit output.

The second branch of the bridge circuit is formed by a series-connected single resistor 22 (R ₂₂ ) and two terminals for connecting the measurement object, which consists of a series-connected resistor 23 (R ₂₃ ) and an inductive coil 24 (L ₂₄ ). In parallel to the coil 24, a resistor 25 (R ₂₅ ) and an inductive coil 26 (L ₂₆ ) are connected in series.

The free output of a single resistor 22 is connected to the first output of the pulse generator, and the common output of this resistor and the first terminal for connecting the two-terminal device of the measurement object is the second output of the bridge circuit output (the second terminal is grounded). Both outputs of the bridge circuit output are connected to the differential input of the null indicator 27, its synchronization input is connected to the second output of the pulse generator, the common bus of the null indicator is grounded.

A bridge meter for the parameters of bipolar operates as follows. In the initial state, the voltages at the input and output of the bridge circuit are zero. We apply to the input of the bridge circuit from the generator 1 a pulse train of a rectangular shape. Under the action of the next pulse in the steady state, unchanging voltages are established in the branches of the bridge circuit. The voltage of the flat peak of the pulse here depends only on the resistances of the resistors 9, 10, 11, 12, 13, 22 and 23. The first condition for the equilibrium of the bridge circuit is

$$A_{\mathrm{one}}=R_{22}\left[R_{\mathrm{eleven}}\left(R_{10}+R_{12}+R_{13}\right)+R_{10}{R}_{13}\right]\neg R_{23}\left[R_9\left(R_{10}+R_{12}+R_{13}\right)+R_{10}{R}_{12}\right]=0.\left(\mathrm{one}\right)$$

By a single adjustment of the resistance value of the reference resistor 13, the flat peak of the pulse nonequilibrium signal is reduced to zero, thereby fulfilling the first equilibrium condition of the bridge circuit (1). The equilibrium of the bridge circuit here and hereinafter is indicated by the zero indicator 27, while the synchronization signal from the second output of the generator 1 to the second input of the zero indicator ensures the stability of its readings.

Further, a sequence of pulses varying linearly is supplied from the generator 1 to the input of the bridge circuit. When the next such pulse is applied, after the end of the transition process, an impulse non-equilibrium signal with a flat top is established at the output of the bridge circuit. The second condition for the equilibrium of the bridge chain is

$$A_2=\left(R_{22}+R_{23}\right)R_{10}{R}_{17}{L}_{\mathrm{fourteen}}+\left(R_{16}+R_{17}\right)\left\{\left[R_{\mathrm{eleven}}{R}_{22}\neg R_{23}\left(R_9+R_{10}\right)\right]L_{\mathrm{fourteen}}\neg D_{\mathrm{one}}{L}_{24}\right\}=0,\left(2\right)$$

where D ₁ = R ₉ (R ₁₀ + R ₁₂ + R ₁₃ ) + R ₁₀ R ₁₂ .

By a single adjustment of the resistance of the reference resistor 17, we bring the flat top of the pulse nonequilibrium signal to zero, thereby fulfilling the second equilibrium condition (2). In this case, the first equilibrium condition (1) is not violated, since the adjustable parameter R ₁₇ is not included in it.

Then, a sequence of quadratic pulses is supplied from the generator 1 to the input of the bridge circuit. When the next such pulse is applied, at the end of the transient process, a pulse equilibrium signal with a flat top is established at the output of the bridge circuit. The third condition for the equilibrium of the bridge chain is

$$\begin{array}{l}{A}_3=R_{\mathrm{eleven}}{R}_{\mathrm{fifteen}}\left[R_{10}\left(R_{21}{R}_{22}\neg R_{\mathrm{twenty}}{R}_{23}\right)\neg R_9{R}_{23}\left(R_{\mathrm{twenty}}+R_{21}\right)\right]L_{\mathrm{fourteen}}{L}_{\mathrm{eighteen}}+\\ +R_{\mathrm{fifteen}}\left(R_{\mathrm{twenty}}+R_{21}\right)\left\{R_{10}{R}_{17}{R}_{22}+\left(R_{23}+R_{25}\right)\left[R_{10}{R}_{17}+\left(R_9+R_{10}\right)\left(R_{16}+R_{17}\right)\right]\right\}\times \\ \times L_{\mathrm{fourteen}}{L}_{24}+\left(R_{\mathrm{twenty}}+R_{21}\right)\{R_{\mathrm{eleven}}{R}_{\mathrm{fifteen}}{R}_{22}\left[R_{25}{L}_{\mathrm{eighteen}}+\left(R_{16}+R_{17}\right)L_{24}\right]L_{\mathrm{fourteen}}\neg \\ \neg R_{25}{D}_{\mathrm{one}}\left[R_{\mathrm{fifteen}}\left(L_{\mathrm{fourteen}}+L_{\mathrm{eighteen}}\right)+\left(R_{16}+R_{17}\right)L_{\mathrm{fourteen}}\right]L_{24}\}=0.\left(3\right)\end{array}$$

By adjusting the resistance of the model resistor R ₂₁ once, we bring the flat peak of the impulse voltage of the disequilibrium to zero and fulfill the third equilibrium condition (3), while the first two equilibrium conditions (1) and (2) are not violated, since the parameter R ₂₁ regulated here is not included.

Next, a sequence of cubic pulses is supplied from the generator 1 to the input of the bridge circuit. When the next such pulse is applied, after the end of the transition process, an impulse non-equilibrium signal with a flat top is established at the output of the bridge circuit. The fourth condition for the equilibrium of the bridge chain is

$$\begin{array}{l}{A}_{\mathrm{four}}=R_{10}{R}_{\mathrm{fifteen}}\left[R_{17}\left(R_{19}+R_{\mathrm{twenty}}+R_{21}\right)+R_{19}{R}_{21}\right]\left[\left(R_{22}+R_{23}\right)\left(L_{24}+L_{26}\right)+R_{25}{L}_{24}\right]L_{\mathrm{fourteen}}{L}_{\mathrm{eighteen}}\neg \\ \neg R_{\mathrm{fifteen}}{R}_{19}\left(R_{\mathrm{twenty}}+R_{21}\right)\left[R_9\left(R_{16}+R_{17}\right)+R_{10}{R}_{16}\right]L_{\mathrm{fourteen}}{L}_{24}{L}_{26}\neg D_{\mathrm{one}}{D}_2{L}_{24}{L}_{26}+\\ +\left[R_{\mathrm{eleven}}{R}_{12}\left(L_{24}{L}_{26}\right)\neg R_{23}\left(R_9+R_{10}\right)\left(L_{24}+L_{26}\right)\neg R_{25}\left(R_9+R_{10}\right)L_{24}\right]D_3{L}_{\mathrm{fourteen}}{L}_{\mathrm{eighteen}}\neg \\ \neg R_{25}\left[R_{19}\left(R_{\mathrm{twenty}}+R_{21}\right)+\left(R_{19}+R_{\mathrm{twenty}}+R_{21}\right)\left(R_{\mathrm{fifteen}}+R_{16}+R_{17}\right)\right]D_{\mathrm{one}}{L}_{\mathrm{fourteen}}{L}_{\mathrm{eighteen}}{L}_{24}=0,\left(\mathrm{four}\right)\end{array}$$

where D ₂ = R ₁₉ (R ₂₀ + R ₂₁ ) (R ₁₅ + R ₁₆ + R ₁₇ ) L ₁₄ +

+ R ₁₅ [R ₁₉ (R ₂₀ + R ₂₁ ) + (R ₁₆ + R ₁₇ ) (R ₁₉ + R ₂₀ + R ₂₁ )] L ₁₈ ;

D ₃ = R ₁₅ [R ₁₉ (R ₂₀ + R ₂₁ ) + (R ₁₆ + R ₁₇ ) (R ₁₉ + R ₂₀ + R ₂₁ )].

By adjusting the resistance of the model resistor 19 once, we bring the flat peak of the nonequilibrium voltage pulse to zero and fulfill the fourth equilibrium condition (4), while the first three equilibrium conditions (1), (2) and (3) are not violated, since the parameter R ₁₉ regulated here not included in them.

The above shows that the separate balancing of the bridge circuit should be carried out in the sequence 13, 17, 21, 19. According to the equations of equilibrium conditions (1), (2), (3) and (4), the desired four parameters are counted: R ₂₃ , L ₂₄ , R ₂₅ , L ₂₆ . The values of the parameters of the elements 9, 10, 11, 12, 14, 15, 16, 18, 20, 22 of the bridge circuit are constant and known. The parameters of the elements 13, 17, 21 and 19 are adjustable and also known.

Thus, this bipolar bridge meter has the property of balancing separately with single adjustments of the resistances of only reference resistors.

Claims (1)

A bridge meter of two-terminal parameters, containing a pulse generator, which consists of pulse shapers with voltage changes over their duration according to the law k ₀ t ⁰ , k ₁ t ¹ , k ₂ t ² and k ₃ t ³ , where k ₀ , k ₁ , k ₂ and k ₃ are constant coefficients, t is the current time from the switch, from the power amplifier and synchronization unit, the output of each pulse shaper is connected to one of the inputs of the switch, its output is connected to the input of the power amplifier, the output of which forms the first output of the pulse generator regarding the "earth", exit the synchronization unit is connected to the input of each pulse shaper (synchronization input), and its output forms the second output (synchronization output) of the pulse generator relative to the ground, the common bus of the pulse generator is grounded; a bridge electrical circuit, which consists of two branches connected in parallel, the first of which includes the first and second resistors and the first inductive coil connected in series, a third resistor connected in series with the second inductive coil connected to the common terminal of the second resistor and the first inductive coil which includes the fourth resistor, the free output of the first resistor is connected to the first output of the pulse generator, the second branch of the bridge circuit includes a series connected single resistor and two terminals for connecting the two-terminal object of measurement, the free output of a single resistor is connected to the first output of the pulse generator, the common output of a single resistor and the first terminal for connecting a two-terminal object of measurement forms one of two outputs of the bridge circuit, the second terminal is grounded, the two-terminal object measurement, in particular, consists of a series-connected first resistor and a first inductive coil, in parallel which are connected in series with a single second resistor and a second inductive coil; a null indicator, to one of the pins of the first (differential) input of which the named one of the two pins of the bridge circuit output is connected, the second output (synchronization output) of the pulse generator is connected to the second input (synchronization output), the common bus of the null indicator is grounded, characterized in that seven additional resistors are introduced into it and the inclusion of the first branch of the bridge circuit is changed, the first and second additional resistors are connected in series and introduced into the first branch of the bridge circuit, the free output of the first the first additional resistor is connected to the common terminal of the available first and second resistors, the free terminal of the second additional resistor is grounded, the third additional resistor is connected between the free terminal of the first available inductive coil and the common terminal of the first and second additional resistors, the fourth additional resistor is connected in parallel with the first inductive coil, a fifth additional resistor is connected between the common terminal of the third and fourth additional resistors and the first inductance ohm coil, as well as the common output of the existing second inductive coil and the fourth available resistor, the sixth and seventh additional resistors are interconnected in series, the free output of the sixth additional resistor is connected to the common output of the third and fourth available resistors, as well as the second inductive coil, the free output of the seventh an additional resistor is connected to a common terminal of an existing fourth resistor and a fifth additional resistor, as well as a second inductive coil, a common terminal Modes sixth and seventh resistors forms another (second) output output bridge circuit, this output is coupled to a second terminal of the first (differential) input null indicator.