CN2709931Y - Constant-flow static resistance strain gauge - Google Patents
Constant-flow static resistance strain gauge Download PDFInfo
- Publication number
- CN2709931Y CN2709931Y CN 200420062671 CN200420062671U CN2709931Y CN 2709931 Y CN2709931 Y CN 2709931Y CN 200420062671 CN200420062671 CN 200420062671 CN 200420062671 U CN200420062671 U CN 200420062671U CN 2709931 Y CN2709931 Y CN 2709931Y
- Authority
- CN
- China
- Prior art keywords
- resistance
- constant current
- circuit
- strain
- bridge circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Abstract
The utility model relates to a constant current type static resistance strain gauge, arranges a constant current source and an electrical analog switch circuit on the input end of the bridge circuit, adopts the switching technique of the constant current stimulating the electron switch, and thoroughly overcomes the abuse of the existing strain gauge using the hand switch and the relay contact to carry out the bridge circuit switching. The utility model excludes the resistance of the electrical analog switch circuit out of the bridge circuit testing the change of the resistance. Thus, the output voltage of the strain gauge is related with the drive current, the strain resistance, the strain gage sensitivity coefficient and the strain value, has no relationship with the wire resistance, and also has no relationship with the electrical analog switch resistance. Simultaneously, the utility model has no bridge circuit non-linearity for large strain measurement. The utility model has small volume, light weight, strong interference rejection, and good stability, is an excellent substitution commodity of the present constant-voltage type static resistance strain gauge, is adapted for the structural stress measuring of many fields of machinery, civil engineering, etc, and is one of the important instrument of the scientific research and teaching.
Description
Technical field
The utility model relates to a kind of instrument of structural member stress test, relates in particular to a kind of constant current mode static resistance strainmeter.
Background technology
Strain ga(u)ge is subjected to stress-strain to be converted to resistance variations component surface, because the member strain is generally less, in order to guarantee certain measuring accuracy, requires the sensitivity of surveying instrument can reach the 1-5 microstrain.The general electric wire strain gauge that adopts is converted to the increment Delta I or the Δ V of curtage to the Δ R/R of strainometer, and amplifies through electron-amplifier, shows with strain numerical value at last or send Computer Processing.Constant voltage static resistance strainmeter at present commonly used, in the direct current bridge of strainmeter, one group of resistance is the balance fixed resistance, one group of resistance is strain ga(u)ge resistance, a resistance is the work strain meter in this group, another resistance is the temperature compensation strainometer, and actual measurement is measured for the multiple spot static strain, is connected to reed switch relay for this reason in the foil gauge resistance loop measuring point is switched.From the practice of using, there are following some shortcomings in existing constant pressure type static resistance strainmeter: the one, and it is non-linear that the electric bridge characteristic exists, and when measuring strain greater than 5000 microstrains, error slightly is equal to or greater than-0.5%; The 2nd, long lead compensation when lead is longer, be revised the strain measured value, and the length of used lead, sectional area all should be identical, if measurement environment is very abominable, then can causes the variation of conductor resistance, thereby influence the precision of strain measurement value; The 3rd, the contact resistance of relay is big, and temperature effect is big, and relay is short serviceable life, and switch speed is slow, and price is high and volume is big.
Goal of the invention
The purpose of this utility model is at existing constant pressure type static resistance strainmeter above shortcomings, a kind of non-linear, no long lead compensation that does not have an electric bridge characteristic is provided and measuring point is switched and the constant current mode static resistance strainmeter of long service life fast.
The purpose of this utility model is achieved through the following technical solutions, a kind of constant current mode static resistance strainmeter, comprise housing, the bridge circuit of forming by sample resistance in external foil gauge resistance and the housing, the differential amplifier that the output terminal of bridge circuit connects, the wave filter that connects behind the differential amplifier, A/D change-over circuit, storer and control circuit is characterized in that the source end of bridge circuit connects the constant current source and the electronic analog switch circuit of serial connection, is connected in series impact damper in the two sample resistance front end place arms.
The utility model is provided with constant current source and electronic analog switch circuit by the input end at bridge circuit, adopt constant current drive electronic switch handoff technique, thoroughly having overcome existing strainmeter uses hand switch and relay contact to carry out all drawbacks that bridge circuit switches, with the resistor chain of electronic analog switch circuit except that changing in the bridge circuit test resistance, therefore the strainmeter output voltage only and exciting current, strain resistor, the foil gauge sensitivity coefficient, strain value is relevant, irrelevant with conductor resistance, also irrelevant with electronic analog swtich resistance, simultaneously, for big strain measurement, there is not bridge circuit non-linear yet, the utility model volume is little, in light weight, antijamming capability is strong, and good stability is the existing fabulous substitute products of constant pressure type static resistance strainmeter, be applicable to machinery, multi-field measurement to structural stress such as civil engineering also is to carry out scientific research, one of important instrument of teaching.
Description of drawings
Accompanying drawing 1 is the utility model partial circuit block diagram;
Accompanying drawing 2 is the utility model partial circuit figure;
In the accompanying drawing, resistance R
1, R
2, the foil gauge resistance R
S1, R
S2, sample resistance R
3, R
4, diode V
1, capacitor C
1, integrated circuit N
1(741), N
2(4051), N
3(LF353), N
4, interface A, B, C, B '.
Embodiment
The utility model is by comprising integrated circuit N in housing, the housing
1(741) and the constant current source formed of peripheral circuit, integrated circuit N
2(4051) electronic analog switch circuit of Zu Chenging, external foil gauge resistance R
S1, R
S2With sample resistance R
3, R
4The bridge circuit of forming, sample resistance R
3, R
4Front end place arm serial connection by integrated circuit N
3(LF353) the integrated circuit N of impact damper of Zu Chenging and bridge circuit output terminal connection
4The wave filter that connects behind differential amplifier of forming and the differential amplifier, A/D change-over circuit, storer and control circuit constitute, and constant current source and the input end that is connected on bridge circuit after electronic analog switch circuit is connected in series are at sample resistance R
3, R
4Preceding serial connection impact damper, effect is that interior half-bridge adopts constant voltage driving by impact damper, constant current source passes through lead, foil gauge R again through electronic analog swtich
S1, R
S2Produce voltage at A, B point, produce voltage by two impact dampers at B ' point again, VB, VB ' send differential amplifier amplification, filtering, AD to gather, and show with strain numerical value at last or send Computer Processing.From accompanying drawing 1 as can be known, VA-VC=(R
S1+ R
S2+r) I, VB-VC=(R
S2+r) I, VB '=(VA+VC)/2, r is a conductor resistance in the formula, R
S1, R
S2Be foil gauge resistance, R
3, R
4It is sample resistance.For being total to compensating measure, active gage R
S1=R+ Δ R, compensating plate R
S2=R.If R
3=R
4, VB '-VB=(VA-VC)/2-(R+r) I=(2R+ Δ R+2r) I/2-(R+r) I=Δ RI/2=IR (Δ R/R)/2=IRK ε/2 then.For two measurements, active gage R
S1=R+ Δ R, active gage R
S2=R-Δ R, VB '-VB=IRK ε.For four measurements, then need not add impact damper, R
3, R
4Be active gage equally, through simple computation, VB '-VB=IRK ε.By analyzing as can be known, no matter the utility model is what bridge circuit form, and the strainmeter output voltage is only relevant, irrelevant with conductor resistance, also irrelevant with electronic analog swtich resistance with exciting current, foil gauge resistance, foil gauge sensitivity coefficient, strain value.Simultaneously, for big strain measurement, there is not bridge circuit non-linear yet.
Claims (4)
1 one kinds of constant current mode static resistance strainmeters, comprise housing, the bridge circuit of forming by sample resistance in external foil gauge resistance and the housing, the differential amplifier that the output terminal of bridge circuit connects, the wave filter that connects behind the differential amplifier, A/D change-over circuit, storer and control circuit, it is characterized in that the source end of bridge circuit connects the constant current source and the electronic analog switch circuit of serial connection, is connected in series impact damper in the two sample resistance front end place arms.
2, constant current mode static resistance strainmeter according to claim 1 is characterized in that constant current source is made of integrated circuit 741 and peripheral circuit thereof.
3, constant current mode static resistance strainmeter according to claim 1 is characterized in that electronic analog switch circuit is made of integrated circuit 4051.
4, constant current mode static resistance strainmeter according to claim 1 is characterized in that impact damper is made of integrated circuit LF353.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420062671 CN2709931Y (en) | 2004-07-14 | 2004-07-14 | Constant-flow static resistance strain gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420062671 CN2709931Y (en) | 2004-07-14 | 2004-07-14 | Constant-flow static resistance strain gauge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2709931Y true CN2709931Y (en) | 2005-07-13 |
Family
ID=34852083
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420062671 Expired - Fee Related CN2709931Y (en) | 2004-07-14 | 2004-07-14 | Constant-flow static resistance strain gauge |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2709931Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103743334A (en) * | 2013-12-20 | 2014-04-23 | 广西科技大学 | Resistance strain gauge |
| CN107152984A (en) * | 2016-03-03 | 2017-09-12 | 沈阳中科奥维科技股份有限公司 | One kind is based on industrial minute-pressure U-tube manometer sensor |
-
2004
- 2004-07-14 CN CN 200420062671 patent/CN2709931Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103743334A (en) * | 2013-12-20 | 2014-04-23 | 广西科技大学 | Resistance strain gauge |
| CN107152984A (en) * | 2016-03-03 | 2017-09-12 | 沈阳中科奥维科技股份有限公司 | One kind is based on industrial minute-pressure U-tube manometer sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |