CN215766881U

CN215766881U - Static resistance strain gauge

Info

Publication number: CN215766881U
Application number: CN202121768191.8U
Authority: CN
Inventors: 杜寿余; 陈冬梅
Original assignee: Yangzhou Yunsheng Electronic Technology Co ltd
Current assignee: Yangzhou Yunsheng Electronic Technology Co ltd
Priority date: 2021-07-31
Filing date: 2021-07-31
Publication date: 2022-02-08
Anticipated expiration: 2031-07-31

Abstract

A static resistance strain gauge. Relates to a resistance strain gauge, in particular to improvement of a static resistance strain gauge. The power supply device comprises a first power supply loop and a second power supply loop, wherein the first power supply loop is used for providing power supply, the first power supply loop is used for supplying power to the filtering and collecting module, and the second power supply loop is used for providing excitation voltage to the bridge circuit module; the double-power-supply mode is adopted, the voltage sampling method is adopted for the excitation voltage of the measuring point bridge circuit, so that when the measuring point of the strain gauge changes, the excitation voltage of the measuring point bridge circuit is constantly equal to 2V, the initial value of each measuring point is not influenced, and the strain measurement precision is improved.

Description

Static resistance strain gauge

Technical Field

The utility model relates to a resistance strain gauge, in particular to improvement of a static resistance strain gauge.

Background

When the existing static resistance strain gauge is connected with a multi-point strain gauge, the initial value of each measuring point changes along with the increase of the number of points of the strain gauge. When the strain gauge is connected with multiple points, the initial value of each measuring point changes along with the increase of the number of the points of the strain gauge. In the 1/4 bridge circuit condition, if the resistance of the strain gauge resistor is R, the current consumption through one strain gauge is VB/(R +120), and the current consumption of N strain gauges is VB/(R + 120). times.N. Under the condition of 1/2 bridge bridges, each measuring point is connected with 2 strain gauges, the current required by one measuring point is VB/2R, and the current required by N measuring points is VB/2R N, under the condition of full bridge bridges, each measuring point is connected with 4 strain gauges, the current required by one measuring point is VB/R, and the current required by N measuring points is VB/R N. Obviously, as the number of strain gauge points to be measured increases, the power supply current consumed increases.

The conventional static resistance strain gauge provides a positive power supply of bridge voltage and a positive power supply of an amplifying and filtering circuit, and the consumed power supply current increases along with the increase of the number of points of a measured strain gauge. When the power supply current increases, the positive power supply voltage for supplying the bridge voltage and the amplifying and filtering circuit gradually decreases, so that the output zero voltage of the operational amplifier of the amplifying and filtering circuit gradually changes. That is, when a plurality of points of the strain gauge are connected, the initial value of each measuring point changes along with the increase of the number of the points of the strain gauge, so that the strain measurement value of each measuring point is influenced.

As the number of the points of the strain gauge to be measured increases, the consumed bridge circuit excitation voltage current increases. As the bridge current increases, the bridge excitation voltage decreases progressively, affecting the strain measurement at each measurement point.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects of the prior art, the utility model provides the static resistance strain gauge with high measurement accuracy, wherein the strain measurement value of each measuring point is unchanged along with the increase of the number of the points of the measured strain gauge.

The utility model is realized by adopting the following technical scheme: the static resistance strain gauge comprises a first power supply loop and a second power supply loop, wherein the first power supply loop is used for providing power, the first power supply loop is used for supplying power to the filtering and collecting module, and the second power supply loop is used for providing excitation voltage to the bridge circuit module;

an excitation voltage sampling module is arranged in the bridge circuit module, a second pin of a voltage-stabilized power supply module N3 in the excitation voltage sampling module is connected with one end of a resistor R5, and the other end of the resistor R5 is connected with one end of a potentiometer RP 3. The other end of the potentiometer RP3 is connected with one end of a resistor R6, the other end of the resistor R6 is grounded, and the center tap of the potentiometer RP3 is connected with the 3 rd pin of the operational amplifier module N4;

the sixth pin of the operational amplifier module N4 is respectively connected with one end of a resistor R7 and one end of a capacitor C7, and the other end of the resistor R7 is respectively connected with the base electrode of the triode V1 and the collector electrode of the triode V2;

the collector of the transistor V1 is connected to the power supply via a resistor R8, the emitter of the transistor V1 is connected to the base of the transistor V2 and is connected to the first pin of the socket XS2 via a resistor R12, and the emitter of the transistor V2 is connected to the first pin of the socket XS 2.

A second pin of the operational amplifier module N4 is connected with the other end of the capacitor C7 and is connected with a second pin of the socket XS2, and a third pin of the socket XS2 is grounded; the first leg of socket XS2 and the second leg of socket XS2 are connected to strain gauge test point stimulus bridge terminals, respectively.

The socket XS1 in the first power supply loop inputs 7V pulsating direct current voltage to the fifth pin of the stabilized voltage supply module N1, the capacitor C1 is a homogenizing capacitor, the 3 rd pin of the stabilized voltage supply module N1 outputs +5V direct current voltage as a positive power supply of the filtering and collecting module, and the second pin and the fourth pin of the stabilized voltage supply module N1 are in short circuit and are grounded.

One end of the resistor R1 is connected with the third pin of the regulated power supply module N1, and the other end of the resistor R1 is connected with one end of the potentiometer RP 1; the other end of the potentiometer RP1 and the center tap of the potentiometer RP1 are in short circuit and connected to one end of a resistor R2, and are also connected to the first pin of the regulated power supply module N1, and the other end of the resistor R2 is grounded.

In the second power supply loop, 7V pulsating direct current voltage is input to the fifth pin of the stabilized voltage supply module N2 through the socket XS1, the capacitor C4 is a homogenizing capacitor, the third pin of the stabilized voltage supply module N2 outputs +5V direct current voltage to serve as a bridge circuit module to provide excitation voltage, and the second pin and the fourth pin of the stabilized voltage supply module N2 are in short circuit and are grounded.

One end of the resistor R3 is connected with the third pin of the regulated power supply module N2, and the other end of the resistor R3 is connected with one end of the potentiometer RP 2; the other end of the potentiometer RP2 and a center tap of the potentiometer RP2 are in short circuit and connected to one end of a resistor R4, and are connected to a first pin of a voltage-stabilized power supply module N2, and the other end of the resistor R4 is grounded;

the third pin of the regulated power supply module N2 is connected to the first pin of the regulated power supply module N3, the third pin of the regulated power supply module N3 is grounded, and the second pin of the regulated power supply module N3 outputs a 2.5V reference voltage.

The voltage-stabilized power supply module N3 is an MC1403 voltage-stabilized power supply module, the operational amplifier module N4 is an OP07 operational amplifier module, the triode V1 is a TIP41 triode, and the triode V2 is a 9014 triode.

Compared with the prior art, the utility model adopts a dual power supply mode, and the measuring point bridge circuit excitation voltage adopts a voltage sampling method, so that when the measuring point of the strain gauge changes, the measuring point bridge circuit excitation voltage is constantly equal to 2V, and the initial value of each measuring point is not influenced, thereby improving the strain measurement precision.

Drawings

Fig. 1 is a circuit schematic of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

As shown in fig. 1, the power supply is divided into two paths, one path is labeled as V +1 and is used for amplification, filtering and acquisition of the transformer; the other path is labeled V +2 and is used for bridge circuit excitation voltage. The double-power-supply mode is adopted, the voltage sampling method is adopted for the excitation voltage of the measuring point bridge circuit, so that when the measuring point of the strain gauge changes, the excitation voltage of the measuring point bridge circuit is constantly equal to 2V, the initial value of each measuring point is not influenced, and the strain measurement precision is improved.

The socket XS1 inputs 7V pulsating direct current voltage to the No. 5 pin of the LM2941 regulated power supply module with the reference number N1, the capacitor C1 is a homogenizing capacitor, and the No. 3 pin of the LM2941 regulated power supply module with the reference number N1 outputs V +1(+5V) direct current voltage as a positive power supply of the strain gauge amplifying, filtering and collecting circuit. The pins 2 and 4 of the LM2941 regulated power supply module, labeled N1, are shorted and grounded.

One end of the resistor R1 is connected with the 3 rd pin of the LM2941 regulated power supply module with the number N1, and the other end of the resistor R1 is connected with one end of the potentiometer RP 1; the other end of the potentiometer RP1 and the center tap of the potentiometer RP1 are in short circuit and connected to one end of a resistor R2, and are also connected to the 1 st pin of the LM2941 regulated power supply module with the reference number N1, and the other end of the resistor R2 is grounded.

The socket XS1 inputs 7V of pulsating DC voltage to the 5 th pin of the LM2941 regulated power supply module with the reference number N2, the capacitor C4 is a homogenizing capacitor, and the 3 rd pin of the LM2941 regulated power supply module with the reference number N2 outputs V +2(+5V) DC voltage as a positive power supply for the bridge circuit excitation voltage. The pins 2 and 4 of the LM2941 regulated power supply module, labeled N2, are shorted and grounded.

One end of the resistor R3 is connected with the 3 rd pin of the LM2941 regulated power supply module with the number N2, and the other end of the resistor R3 is connected with one end of the potentiometer RP 2; the other end of the potentiometer RP2 and the center tap of the potentiometer RP2 are in short circuit and connected to one end of a resistor R4, and are also connected to the 1 st pin of the LM2941 regulated power supply module with the reference number N2, and the other end of the resistor R4 is grounded.

V +2 is connected to pin 1 of the MC1403 voltage-stabilized power module with the reference number N3, pin 3N of the MC1403 voltage-stabilized power module with the reference number N3 is grounded, and pin 2 of N3 outputs 2.5V reference voltage.

In order to solve the problem that the bridge circuit excitation voltage varies with the number of measuring points, the application patent adopts a bridge circuit excitation voltage sampling technology (RS +), wherein a 2 nd pin of an MC1403 voltage-stabilized power supply module with the reference number of N3 is connected with one end of a resistor R5, and the other end of the resistor R5 is connected with one end of a potentiometer RP 3. The other end of the potentiometer RP3 is connected with one end of a resistor R6 in a resistance mode, the other end of the resistor R6 is grounded, and the center tap of the potentiometer RP3 is connected with the 3 rd pin of the OP07 operational amplifier module with the number of N4.

The pin 6 of the OP07 OP-amp module labeled N4 is connected to one end of the resistor R7 and to one end of the capacitor C7. The other end of the resistor R7 is connected to pin 1 (base) of the TIP41 transistor labeled V1 and to pin 3 (collector) of the 9014 transistor labeled V2.

The 2 nd pin (collector) of the TIP41 transistor labeled V1 is connected to the power supply via a resistor R8, and the 3 rd pin (emitter) of the TIP41 transistor labeled V1 is connected to the 1 st pin (base) of the 9014 transistor labeled V2, and is connected to the 1 st pin (bridge circuit excitation voltage P +) of the socket XS2 via a resistor R12.

The 3 rd pin (emitter) of the 9014 transistor labeled as V2 is connected to the 1 st pin (bridge excitation voltage P +) of the socket XS2, and when the current of the 1 st pin (bridge excitation voltage P +) of the socket XS2 is greater than Vbe (9014 transistor labeled as V2)/R12, the base (b) and the emitter (e) of the 9014 transistor labeled as V2 are conducted. This provides short circuit protection when the bridge excitation voltage P + is shorted to ground or the current is too large.

The 2 nd pin of the OP07 OP amp module, labeled N4, is connected to the other end of capacitor C7 and to pin 2 (RS +) of socket XS2, and pin 3 of socket XS2 is connected to ground. A1 st pin (P +) of the socket XS2 is connected with one lead, a 2 nd pin (RS +) of the socket XS2 is connected with the other lead, and the 2 leads are connected to a strain gauge measuring point excitation bridge voltage end. When the voltage at the excitation bridge voltage end of the strain gauge measuring point becomes larger or smaller, the voltage at the excitation bridge voltage end of the strain gauge measuring point is equal to the 2V reference voltage because RS + is connected with the 2 nd pin (inverting end) of the OP07 operational amplifier module with the reference number of N4, the 3 rd pin (non-inverting end) of the OP07 operational amplifier module with the reference number of N4 is the 2V reference voltage (the 3 rd pin of the OP07 operational amplifier module with the reference number of N4), and the voltage at the excitation bridge voltage end of the strain gauge measuring point is equal to the 2V reference voltage because of the existence (smoothing effect) of the capacitor C7.

The double-power-supply mode is adopted, the voltage sampling method is adopted for the excitation voltage of the measuring point bridge circuit, so that when the measuring point of the strain gauge changes, the excitation voltage of the measuring point bridge circuit is constantly equal to 2V, the initial value of each measuring point is not influenced, and the strain measurement precision is improved.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.

Claims

1. Static resistance strain gauge, including first supply circuit and second supply circuit for providing the power, its characterized in that: the first power supply loop supplies power to the filtering and collecting module, and the second power supply loop supplies excitation voltage to the bridge circuit module;

an excitation voltage sampling module is arranged in the bridge circuit module, a second pin of a voltage-stabilized power supply module N3 in the excitation voltage sampling module is connected with one end of a resistor R5, and the other end of the resistor R5 is connected with one end of a potentiometer RP 3;

the other end of the potentiometer RP3 is connected with one end of a resistor R6, the other end of the resistor R6 is grounded, and the center tap of the potentiometer RP3 is connected with the 3 rd pin of the operational amplifier module N4;

the collector of the triode V1 is connected with a power supply through a resistor R8, the emitter of the triode V1 is connected with the base of the triode V2 and is connected with the first pin of the socket XS2 through a resistor R12, and the emitter of the triode V2 is connected with the first pin of the socket XS 2;

2. The static resistive strain gauge of claim 1, wherein: the socket XS1 in the first power supply loop inputs 7V pulsating direct current voltage to the fifth pin of the stabilized voltage supply module N1, the capacitor C1 is a homogenizing capacitor, the 3 rd pin of the stabilized voltage supply module N1 outputs +5V direct current voltage as a positive power supply of the filtering and collecting module, and the second pin and the fourth pin of the stabilized voltage supply module N1 are in short circuit and are grounded.

3. The static resistive strain gauge of claim 2, wherein: one end of the resistor R1 is connected with the third pin of the regulated power supply module N1, and the other end of the resistor R1 is connected with one end of the potentiometer RP 1; the other end of the potentiometer RP1 and the center tap of the potentiometer RP1 are in short circuit and connected to one end of a resistor R2, and are also connected to the first pin of the regulated power supply module N1, and the other end of the resistor R2 is grounded.

4. The static resistive strain gauge of claim 1, wherein: in the second power supply loop, 7V pulsating direct current voltage is input to the fifth pin of the stabilized voltage supply module N2 through the socket XS1, the capacitor C4 is a homogenizing capacitor, the third pin of the stabilized voltage supply module N2 outputs +5V direct current voltage to serve as a bridge circuit module to provide excitation voltage, and the second pin and the fourth pin of the stabilized voltage supply module N2 are in short circuit and are grounded.

5. The static resistive strain gauge of claim 4, wherein: one end of the resistor R3 is connected with the third pin of the regulated power supply module N2, and the other end of the resistor R3 is connected with one end of the potentiometer RP 2; the other end of the potentiometer RP2 and a center tap of the potentiometer RP2 are in short circuit and connected to one end of a resistor R4, and are connected to a first pin of a voltage-stabilized power supply module N2, and the other end of the resistor R4 is grounded;

6. The static resistive strain gauge of claim 1, wherein: the voltage-stabilized power supply module N3 is an MC1403 voltage-stabilized power supply module, the operational amplifier module N4 is an OP07 operational amplifier module, the triode V1 is a TIP41 triode, and the triode V2 is a 9014 triode.