CN202119466U - Measuring device of differential resistance type sensor - Google Patents
Measuring device of differential resistance type sensor Download PDFInfo
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- CN202119466U CN202119466U CN2011202009996U CN201120200999U CN202119466U CN 202119466 U CN202119466 U CN 202119466U CN 2011202009996 U CN2011202009996 U CN 2011202009996U CN 201120200999 U CN201120200999 U CN 201120200999U CN 202119466 U CN202119466 U CN 202119466U
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- type sensor
- resistance type
- differential resistance
- image current
- microprocessor
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Abstract
The utility model relates to a measuring device of a differential resistance type sensor, comprising an image current generator, a line selector switch circuit, an amplification and rectification circuit, an AD converter and a microprocessor which are connected in sequence, wherein the image current generator generates a pair of image currents (I1, I2) and is connected to the two ends of a differential resistance type sensor through the line selector switch circuit, the line selector switch outputs voltages (U1, U2) outputted by the two ends of the differential resistance type sensor in forward connection and backward connection to the microprocessor after the voltages (U1, U2) pass through the amplification and rectification circuit and the AD converter sequentially, the microprocessor obtains the physical quantities to be measured of the differential resistance type sensor according to the relationship of the voltages (U1, U2) of the two ends of the differential resistance type sensor and the image currents (I1, I2), thus realizing the measuring of the differential resistance type sensor. The measuring device can obtain an ideal measuring sensitivity and an ideal measure precision, and improve the reliability of the differential resistance type sensor.
Description
Technical field
The utility model relates to the measurement mechanism of the differential resistance type sensor in the safety monitoring instrument of health monitoring technical field, particularly Geotechnical Engineering of Geotechnical Engineering.
Background technology
In the health monitoring technical field of Geotechnical Engineering; Usually adopt the physical quantitys such as ess-strain, temperature, seam aperture, seepage and distortion of differential resistance type sensor safety monitoring instrument monitoring Geotechnical Engineerings such as (or claiming difference resistance formula instrument), in order to the healthy and safe situation of analysis and judgement Geotechnical Engineering.
Differential resistance type sensor is that the steel wire by two identical materials (the identical ρ of being of resistivity), same cross-sectional long-pending (being s) is composed of; Two steel wire initial lengths equate; Be made as L; In perception external influence power F (can be the measuring-signals such as ess-strain, temperature, seam aperture, seepage and distortion of dam and Geotechnical Engineering), wherein one group of stretcher strain that steel wire can produce Δ L, the compression deformation that another group steel wire then can produce Δ L.In elastic range,
wherein K is known constant number.And the resistance value of two steel wires is respectively
The initial resistivity value that other establishes two steel wires is R, then
Be R=(R
1+ R
2)/2.Therefore:
Thus, external influence power F is R
1/ R
2The single function of (being called resistance ratio) is through measure R
1/ R
2Just can realize measurement to F.If establish Δ R=R
1-R
2, then
F is the single function of Δ R/R, can realize the measurement to F too through measuring Δ R/R.
Generally adopt at present direct amplifying method or group bridge method to realize the measurement function of difference resistance formula instrument, wherein directly amplifying method has adopted measuring principle the most intuitively, through the clear resistance measuring circuit of simplicity of design, directly obtains resistance R
1And resistance R
2Measured value, obtain Δ R and R through numerical evaluation then, obtain the result of calculation of F at last.Its advantage is that principle is directly perceived, circuit is simple; The process object of metering circuit has not only comprised Δ R but also has comprised intrinsic resistance component value R but shortcoming is; And Δ R is numerically much smaller than R, and it is undesirable to cause measuring sensitivity and measuring accuracy, so measurement effect is bad.Employing group bridge method; Can directly obtain Δ R data and effectively overcome the influence of fixed resistance component value R, but organize the measured value that the bridge method can not directly obtain R, so need to increase in addition the R metering circuit measuring accuracy; Will increase the complicacy of metering circuit like this; In addition, group bridge method also has higher accuracy requirement to joining the required resistance R of bridge, so increased the circuit design difficulty.
The healthy and safe condition monitoring of Geotechnical Engineering is most important, and the accuracy of guaranteeing measurement result is a top priority.Therefore, necessary principle of work to difference resistance formula instrument designs a kind of brand-new measuring method, in the hope of obtaining very desirable measurement sensitivity and measuring accuracy.
The utility model content
The utility model is not easy to obtain high-acruracy survey result's problem to existing differential resistance type sensor, and a kind of measurement mechanism of novel differential resistance type sensor is provided, and this device can obtain very desirable measurement sensitivity and measuring accuracy.
The technical scheme of the utility model is following:
A kind of measurement mechanism of differential resistance type sensor, said differential resistance type sensor comprise the resistance (R of two series connection
1, R
2), it is characterized in that comprise the image current generator, line select switch circuit, amplification and rectification circuit, AD converter and single-chip microcomputer or the microprocessor that connect successively, said image current generator produces a pair of image current (I
1, I
2) and the via line selected on-off circuit be connected respectively to the two ends of differential resistance type sensor; Said image current equal and opposite in direction or approximately equal; In the opposite direction; Said line select switch circuit realizes that image current is connected with the forward at differential resistance type sensor two ends and the switching that oppositely is connected, and line select switch connects forward and the voltage (U that oppositely is connected the differential resistance type sensor two ends of output
1, U
2) successively through inputing to single-chip microcomputer or microprocessor behind amplification and rectification circuit and the AD converter, said single-chip microcomputer or microprocessor obtain to be connected and the voltage (U that oppositely is connected the differential resistance type sensor two ends of output with forward
1, U
2) become to confirm the numerical value (N of proportionate relationship
1, N
2), again according to the voltage (U at the differential resistance type sensor two ends that obtain
1, U
2) and image current (I
1, I
2) between relation obtain the measurand of differential resistance type sensor, realize the measurement of differential resistance type sensor.
Said image current generator comprises two current sources, and said two current sources produce image current (I
1, I
2) and exporting the two ends of differential resistance type sensor to, the negative pole of said two current sources links to each other, and the node between two negative poles that link to each other leads to lead, and the other end of said lead is connected to node between two resistance of differential resistance type sensor.
Said line select switch circuit links to each other with single-chip microcomputer or microprocessor, and single-chip microcomputer or microprocessor send command control link selected on-off circuit selection forward and connect and oppositely be connected.
Said line select switch circuit comprises electronic switch or relay switch.
Said AD converter is the high-precision AD converter.
The technique effect of the utility model is following:
The measurement mechanism of the differential resistance type sensor that the utility model relates to; Comprise the image current generator, line select switch circuit, amplification and rectification circuit, AD converter and the single-chip microcomputer (or microprocessor) that connect successively, the image current generator produces a pair of image current (I
1, I
2) and the via line selected on-off circuit be connected respectively to the two ends of differential resistance type sensor; Realize that through the line select switch circuit image current is connected with the forward at differential resistance type sensor two ends and the switching that oppositely is connected, line select switch connects forward and the voltage (U that oppositely is connected the differential resistance type sensor two ends of output
1, U
2) successively through inputing to single-chip microcomputer (or microprocessor) behind amplification and rectification circuit and the AD converter, single-chip microcomputer (or microprocessor) obtains to be connected and the voltage (U that oppositely is connected the differential resistance type sensor two ends of output with forward
1, U
2) become to confirm the numerical value (N of proportionate relationship
1, N
2), thereby realize that forward is measured and reverse the measurement, and finally obtain the measurand of differential resistance type sensor, as obtaining R
1-R
2(being Δ R) and R
1+ R
2The numerical value of (being 2R) and resistance ratio R1/R2 is realized the measurement of external influence power F, realizes the measurement of differential resistance type sensor.This device of the utility model because and indirectly measurement intrinsic resistance component value R with numerically much smaller than the Δ R of R, so solved the low and unfavorable problem of measuring accuracy of measurement sensitivity of existing direct amplifying method existence; Need not to organize bridge simultaneously, set up the R metering circuit and be equipped with the demanding resistance R of accuracy class, so reduced the measurement cost, simplified circuit design, the reliability that has improved measuring accuracy simultaneously and improved differential resistance type sensor.Through introducing image current; Isolate the intrinsic resistance component value R and the resistance difference variation delta R of differential resistance type sensor effectively; Demonstrated fully the principle of work of differential resistance type sensor; Therefore can obtain very desirable measurement sensitivity and measuring accuracy, improve the accuracy and the reliability of differential resistance type sensor, the safety monitoring that can satisfy Geotechnical Engineering is to the strict demand of the accuracy of the reliability of safety monitoring instrument and measurement data.
Description of drawings
Fig. 1 is the differential resistance type sensor equivalent circuit diagram.
Fig. 2 is that the forward of the measurement mechanism of the utility model differential resistance type sensor connects equivalent circuit diagram.
Fig. 3 is the reverse connection equivalent circuit diagram of the measurement mechanism of the utility model differential resistance type sensor.
The preferred structure synoptic diagram of the measurement mechanism of the differential resistance type sensor that Fig. 4 relates to for the utility model.
Embodiment
Below in conjunction with accompanying drawing the utility model is described.
The utility model discloses a kind of device that differential resistance type sensor is measured, the measurand of present embodiment is a differential resistance sensor, and this differential resistance type sensor is made up of two identical materials, the long-pending steel wire of same cross-sectional.Differential resistance type sensor can equivalence on electric becomes the resistance R of two series connection
1And R
2, equivalent circuit diagram as shown in Figure 1 is drawn five measuring junctions: draw lead 1 and 2 at the A of differential resistance type sensor end, in resistance R altogether between the two ends of differential resistance type sensor and two resistance
1And R
2Between node C draw lead 3, draw lead 4 and 5 at the B of differential resistance type sensor end.
The measurement mechanism of the differential resistance type sensor that the utility model relates to; This measurement mechanism preferred structure synoptic diagram is as shown in Figure 4, comprises image current generator, line select switch circuit, amplification and rectification circuit, high-precision AD converter and the microprocessor (also can select single-chip microcomputer or other key process unit) that connect successively.
Wherein, the part except that differential resistance type sensor of the structure of image current generator such as Fig. 2 or Fig. 3 comprises two current sources, and this two current source produces image current I
1And I
2And export A, the B two ends of differential resistance type sensor to; The negative pole of two current sources links to each other; And the node between two negative poles that link to each other leads to lead; The other end of said lead is used to be connected to node C between two resistance of differential resistance type sensor, also is appreciated that to the lead 3 of drawing from node C between two resistance of differential resistance type sensor to be connected to the node between the negative pole of two current sources.
The image current generator produces a pair of image current I
1And I
2And the flow through two ends of differential resistance type sensor of via line selected on-off circuit; This image current equal and opposite in direction or approximately equal; In the opposite direction; The switching that the line select switch circuit is realized that image current is connected with the forward at differential resistance type sensor two ends and oppositely is connected connects, oppositely connects the voltage U that obtains the differential resistance type sensor two ends through forward respectively
AB, obtain U
1, U
2, according to the voltage U at the differential resistance type sensor two ends that obtain
1, U
2With/difference result of calculation and image current I
1And I
2Between definite relation of existing calculate respectively and obtain Δ R and R, and finally calculate the measurand of differential resistance type sensor, like resistance ratio R1/R2, thereby realize the measurement function of differential resistance type sensor.
The equivalent circuit diagram that forward connects is as shown in Figure 2, and two current sources are introduced image current I respectively
1And I
2To differential resistance type sensor AB two ends, i.e. I
1Link to each other I with lead 1
2Link to each other with lead 5, two current source negative poles link to each other, and the node between this continuous negative pole links to each other with lead 3, and it is U that the forward at differential resistance type sensor AB two ends is measured output voltage
1, the concrete statement suc as formula (1):
U
1＝I
1*R
1-I
2*R
2 (1)
The reverse equivalent circuit diagram that connects is as shown in Figure 3, and two current sources are introduced image current I respectively
1And I
2To differential resistance type sensor AB two ends, i.e. I
1Link to each other I with lead 5
2Link to each other with lead 1, also be appreciated that into, oppositely connect relative forward and connect: image current I
1And I
2Constant, with A, the displacement of B two ends of the differential resistance type sensor of introducing.Two current source negative poles link to each other, and the node between this continuous negative pole links to each other with lead C3, and the reverse measurement output voltage at differential resistance type sensor AB two ends is U
2, the concrete statement suc as formula (2):
U
2＝I
1*R
2-I
2*R
1 (2)
Get formula (3) by formula (1)-Shi (2):
U
1-U
2＝(I
1+I
2)*(R
1-R
2)＝(I
1+I
2)*ΔR (3)
Get formula (4) by formula (3)
ΔR＝(U
1-U
2)/(I
1+I
2) (4)
Get formula (5) by formula (1)+formula (2):
U
1+U
2＝(I
1-I
2)*(R
1+R
2)＝(I
1-I
2)*2R (5)
Get formula (6) by formula (5)
R＝(U
1+U
2)/2(I
1-I
2) (6)
Because I
1And I
2Be known, so obtaining U
1And U
2Measured value after, just can obtain the numerical value of Δ R by formula (4), can obtain the numerical value of R by formula (6), at last through calculating the result of calculation that obtains external influence power F.
According to the characteristic of differential resistance type sensor, under the constant situation of environment temperature, R is a steady state value, at this time just need not to be calculated by formula (6), in this case, can choose I
1=I
2But in most cases, the variation of environment temperature is inevitable, and the numerical value of R can slightly change with temperature, at this time just need measure in real time, and through type (6) calculates and obtains, and at this time no longer is fit to choose I
1=I
2, and should choose approximately equal, separate to guarantee formula (6).
Above-mentioned forward connects and oppositely is connected through the realization of line select switch circuit, and this line select switch circuit can be through microprocessor control, and the line select switch circuit can comprise electronic switch or relay switch.Sending the command control link selected on-off circuit by microprocessor selects forward to connect to measure with reverse the connection to measure; Sending the command control link selected on-off circuit like microprocessor selects forward to connect; The image current generator carried out forward with differential resistance type sensor by equivalent circuit diagram shown in Figure 2 and was connected the output voltage signal U of Fig. 2 circuit this moment
1, i.e. voltage signal U
1Input to amplification and rectification circuit and amplify shaping, pass through the high-precision AD converter again after, microprocessor obtains value corresponding N
1, accomplish the forward measuring process; Microprocessor sends the command control link selected on-off circuit and selects reverse the connection, and this moment, the image current generator oppositely was connected the output voltage signal U of Fig. 3 circuit by equivalent circuit diagram shown in Figure 3 with differential resistance type sensor
2, i.e. voltage signal U
2Input to amplification and rectification circuit and amplify shaping, pass through the high-precision AD converter again after, microprocessor obtains value corresponding N
2, accomplish the forward measuring process.After in case amplification and rectification circuit and AD converter are confirmed, N
1With U
1Between and N
2With U
2Between just have the proportionate relationship of confirming, microprocessor can be calculated and obtain U
1, U
2, suppose that scale-up factor is k, then N
1=k * U
1, N
2=k * U
2By formula (4), Δ R=(N
1-N
2)/k (I
1+ I
2), since k, I
1, I
2All are known quantities,, can obtain the numerical result of Δ R so pass through the numerical evaluation of microprocessor.By formula (6), R=(N
1+ N
2)/2k (I
1-I
2), through the numerical evaluation of microprocessor, can obtain the numerical result of R, can also calculate the resistance ratio R of GB regulation
1/ R
2Numerical value, finally calculate the numerical result of F, with the measurement of realization differential resistance type sensor according to the definite relation that exists between external influence power F and the Δ R/R.
In present embodiment, like I
1=6mA, I
2=5mA, k=106/v measures acquisition N through the forward connection
1=45000, measure acquisition N through reverse connection
2=40000, Δ R=0.45 Ω then, R=42.5 Ω.Simultaneously: R
1/ R
2=10106.4 * 10
-4, R
1+ R
2=85.00 Ω.The resistance ratio R that calculates
1/ R
2Meet national regulation 0.8～1.2 between.Under the known situation of K, just can calculate the numerical value of F according to formula
.
Should be pointed out that the above embodiment can make those skilled in the art more fully understand the invention, but do not limit the present invention in any way creation.Therefore; Although this instructions has carried out detailed explanation with reference to accompanying drawing and embodiment to the invention,, those skilled in the art are to be understood that; Still can make amendment or be equal to replacement the invention; In a word, all do not break away from the technical scheme and the improvement thereof of the spirit and the scope of the invention, and it all should be encompassed in the middle of the protection domain of the invention patent.
Claims (5)
1. the measurement mechanism of a differential resistance type sensor, said differential resistance type sensor comprises the resistance (R of two series connection
1, R
2), it is characterized in that comprise the image current generator, line select switch circuit, amplification and rectification circuit, AD converter and single-chip microcomputer or the microprocessor that connect successively, said image current generator produces a pair of image current (I
1, I
2) and the via line selected on-off circuit be connected respectively to the two ends of differential resistance type sensor; Said image current equal and opposite in direction or approximately equal; In the opposite direction; Said line select switch circuit realizes that image current is connected with the forward at differential resistance type sensor two ends and the switching that oppositely is connected, and line select switch connects forward and the voltage (U that oppositely is connected the differential resistance type sensor two ends of output
1, U
2) successively through inputing to single-chip microcomputer or microprocessor behind amplification and rectification circuit and the AD converter, said single-chip microcomputer or microprocessor obtain to be connected and the voltage (U that oppositely is connected the differential resistance type sensor two ends of output with forward
1, U
2) become to confirm the numerical value (N of proportionate relationship
1, N
2), again according to the voltage (U at the differential resistance type sensor two ends that obtain
1, U
2) and image current (I
1, I
2) between relation obtain the measurand of differential resistance type sensor, realize the measurement of differential resistance type sensor.
2. the measurement mechanism of differential resistance type sensor according to claim 1 is characterized in that, said image current generator comprises two current sources, and said two current sources produce image current (I
1, I
2) and exporting the two ends of differential resistance type sensor to, the negative pole of said two current sources links to each other, and the node between two negative poles that link to each other leads to lead, and the other end of said lead is connected to node between two resistance of differential resistance type sensor.
3. the measurement mechanism of differential resistance type sensor according to claim 2; It is characterized in that; Said line select switch circuit links to each other with single-chip microcomputer or microprocessor, and single-chip microcomputer or microprocessor send command control link selected on-off circuit selection forward and connect and oppositely be connected.
4. the measurement mechanism of differential resistance type sensor according to claim 3 is characterized in that, said line select switch circuit comprises electronic switch or relay switch.
5. the measurement mechanism of differential resistance type sensor according to claim 1 is characterized in that, said AD converter is the high-precision AD converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202009996U CN202119466U (en) | 2011-06-15 | 2011-06-15 | Measuring device of differential resistance type sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202009996U CN202119466U (en) | 2011-06-15 | 2011-06-15 | Measuring device of differential resistance type sensor |
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| Publication Number | Publication Date |
|---|---|
| CN202119466U true CN202119466U (en) | 2012-01-18 |
Family
ID=45460523
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011202009996U Expired - Lifetime CN202119466U (en) | 2011-06-15 | 2011-06-15 | Measuring device of differential resistance type sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202119466U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102288337A (en) * | 2011-06-15 | 2011-12-21 | 基康仪器(北京)有限公司 | Method and device for measuring differential resistance type sensor |
| CN111147264A (en) * | 2019-12-23 | 2020-05-12 | 上海申矽凌微电子科技有限公司 | Two-wire sensor communication device and method |
-
2011
- 2011-06-15 CN CN2011202009996U patent/CN202119466U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102288337A (en) * | 2011-06-15 | 2011-12-21 | 基康仪器(北京)有限公司 | Method and device for measuring differential resistance type sensor |
| CN111147264A (en) * | 2019-12-23 | 2020-05-12 | 上海申矽凌微电子科技有限公司 | Two-wire sensor communication device and method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20120118 Effective date of abandoning: 20130313 |
|
| RGAV | Abandon patent right to avoid regrant |