CN108051641A - For the measuring circuit of measuring loop resistance - Google Patents
For the measuring circuit of measuring loop resistance Download PDFInfo
- Publication number
- CN108051641A CN108051641A CN201710934094.3A CN201710934094A CN108051641A CN 108051641 A CN108051641 A CN 108051641A CN 201710934094 A CN201710934094 A CN 201710934094A CN 108051641 A CN108051641 A CN 108051641A
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- Prior art keywords
- voltage
- loop resistance
- measuring
- amplifier
- current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
Abstract
The present invention provides the measuring circuits for measuring loop resistance, belong to microresistivity survey field, and measuring circuit includes experiment power supply, loop resistance, sample circuit, microcontroller, voltage amplifier, A/D converter, instrument amplifier.With reference to the connection relation of each device in above-mentioned measuring circuit, by using the voltage and current of dynamic zero resetting method measuring loop resistance, in the state that experiment power supply is closed, first time measurement is carried out to the voltage and current of loop resistance, voltage and current will be got and be denoted as zero point；In the state that experiment power supply starts, second is carried out to the voltage and current of loop resistance to measure, will be got after voltage and current subtracts the voltage and current as zero point, itself divided by amplification factor are obtained into accurate voltage and current, and then from the influence of Amplifier Temperature drift so that measurement result is accurate.
Description
Technical field
The invention belongs to microresistivity survey fields, the more particularly to measuring circuit for measuring loop resistance.
Background technology
During measuring loop resistance, due to being influenced by factors such as temperature, use condition, environment so that there are temperature for amplifier
The problem of drift, wherein, the accuracy of amplifier directly affects measurement result.
At present, in order to which the voltage and current of accurate measuring loop resistance uses extremely low offset voltage, expensive amplifier, but
Amplifier is still influenced can still there are problems that temperature drift by external factor, and measurement result is caused deviation occur.
The content of the invention
In order to solve shortcoming and defect in the prior art, the present invention provides surveyed by using dynamic zero resetting method
The voltage and current of loop resistance is measured, and then from the influence of Amplifier Temperature drift, improves the survey of the accuracy of test result
Measure circuit.
In order to reach above-mentioned technical purpose, the present invention provides the measuring circuit for measuring loop resistance, the measurement
Circuit includes experiment power supply, and loop resistance, sample circuit, microcontroller, the loop resistance are connected on the experiment power supply
Output terminal be connected with the sample circuit, the output terminal of the sample circuit is connected with voltage amplifier, the voltage amplification
The output terminal of device is connected with A/D converter, and the output terminal of the A/D converter is connected with the microcontroller, the circuit electricity
Another output terminal of resistance is connected with instrument amplifier, and the output terminal of the instrument amplifier is connected with the A/D converter, described
The gain control end of instrument amplifier is connected with microcontroller.
Optionally, the sample circuit includes sampling resistor, and the type of the sampling resistor is four terminal resistances.
Optionally, the voltage amplifier have inverting input and in-phase input end, the inverting input with it is described
The sampling resistor is equipped between in-phase input end.
Optionally, feedback resistance Rf, institute are equipped between the inverting input of the voltage amplifier and the output terminal of itself
The inverting input for stating voltage amplifier is grounded through current-limiting resistance R0.
Optionally, the instrument amplifier has in-phase input end and inverting input, the same phase of the instrument amplifier
The loop resistance is equipped between the inverting input of input terminal and the instrument amplifier.
Optionally, at least there are two input terminals for the A/D converter.
Optionally, relay is equipped between the experiment power supply and the microcontroller.
The advantageous effect that technical solution provided by the invention is brought is：
With reference to the connection relation of each device in above-mentioned measuring circuit, by using dynamic zero resetting method measuring loop resistance
Voltage and current, in the state that experiment power supply is closed, first time measurement is carried out to the voltage and current of loop resistance, will be got
Voltage and current is denoted as zero point；In the state that experiment power supply starts, second is carried out to the voltage and current of loop resistance and is measured, it will
It gets after voltage and current subtracts the voltage and current as zero point, itself divided by amplification factor is obtained into accurate voltage and current, into
And from the influence of Amplifier Temperature drift so that measurement result is accurate.
Description of the drawings
It, below will be to attached drawing needed in embodiment description in order to illustrate more clearly of technical scheme
It is briefly described, it should be apparent that, the accompanying drawings in the following description is only some embodiments of the present invention, general for this field
For logical technical staff, without creative efforts, other attached drawings are can also be obtained according to these attached drawings.
Fig. 1 is the structure diagram provided by the present invention for the measuring circuit of measuring loop resistance；
Fig. 2 is the circuit connection diagram provided by the present invention for the measuring circuit of measuring loop resistance.
Specific embodiment
To make the structure of the present invention and advantage clearer, the structure of the present invention is made further below in conjunction with attached drawing
Description.
Embodiment one
The present invention provides the measuring circuit for measuring loop resistance, the measuring circuit includes experiment power supply, described
Loop resistance, sample circuit, microcontroller are connected on experiment power supply, the output terminal of the loop resistance is connected with the sampling
Circuit, the output terminal of the sample circuit are connected with voltage amplifier, and the output terminal of the voltage amplifier is connected with A/D conversions
Device, the output terminal of the A/D converter are connected with the microcontroller；Another output terminal of the loop resistance is connected with instrument
Amplifier, the output terminal of the instrument amplifier are connected with the A/D converter, and the gain control end of the instrument amplifier connects
It is connected to microcontroller.
In force, as shown in Figure 1, in order to avoid because for measuring the amplifier of voltage and current, there are low pressure imbalance, temperature
The situation of drift is spent, and then measurement result is caused deviation occur.Therefore, the voltage and current of measuring loop resistance uses dynamic zero resetting
Method specifically measures loop resistance twice, measures for the first time, microcontroller is made to close experiment power supply, in experiment power supply
When being closed, the analog quantity electric current of sample circuit acquisition circuit resistance will collect analog quantity electric current and be transmitted to voltage
Amplifier, voltage amplifier carries out preset multiple amplification to analog quantity electric current, and then amplified analog quantity electric current is converted through A/D
Digital quantity electric current is converted into after device, and digital quantity electric current is transmitted to microcontroller, microcontroller reads digital quantity electric current, and will
The digital quantity electric current is denoted as zero point.
Meanwhile the analog quantity voltage of instrument amplifier acquisition circuit resistance, due to A/D converter, there are readings to preset model
It encloses, when the analog quantity voltage that instrument amplifier collects is not in the reading preset range of A/D converter, instrument amplifier just will
It collects voltage and is transmitted to microcontroller through gain control end, make microcontroller by controlling gain control end to analog quantity voltage
Preset multiple amplification is carried out, and then amplified analog quantity voltage is converted into digital quantity voltage through A/D converter, microcontroller is read
Digital quantity voltage is taken, and the digital quantity voltage is denoted as zero point.
Second of measurement, makes microcontroller firing test power supply, when experiment power supply is in the state started, then tests electricity
Source output is more than 100A electric currents, the analog quantity electric current of sampling resistor acquisition circuit resistance, and analog quantity electric current is transported to voltage and is put
Big device, voltage amplifier carries out preset multiple amplification to analog quantity electric current, and then amplified analog quantity electric current is through A/D converter
Digital quantity electric current is converted into, microcontroller reads digital quantity electric current, digital quantity electric current is subtracted the digital quantity electric current as zero point
Afterwards divided by preset multiple obtains accurate digital quantity electric current.
Meanwhile the analog quantity voltage of instrument amplifier measuring loop resistance, due to A/D converter, there are readings to preset model
It encloses, when the analog quantity voltage that instrument amplifier collects is not in the reading preset range of A/D converter, instrument amplifier just will
It collects voltage and is transmitted to microcontroller through gain control end, make microcontroller by controlling gain control end to analog quantity voltage
Preset multiple amplification is carried out, and then amplified analog quantity voltage is converted into digital quantity voltage through A/D converter, microcontroller is read
Digital quantity voltage is taken, after digital quantity voltage is subtracted the digital quantity voltage as zero point divided by preset multiple obtains accurate number
Measure voltage.
Since Amplifier Temperature drift variation is slower, every time the voltage and current of loop resistance is required for being surveyed twice
Amount in the state that experiment power supply is closed, carries out first time school zero to the voltage and current of loop resistance and measures, will get voltage
Electric current is denoted as zero point；In the state that experiment power supply starts, second is carried out to the voltage and current of loop resistance and is measured, will be obtained
After subtracting the voltage and current as zero point to voltage and current, itself divided by amplification factor are obtained into accurate voltage and current, into without
It is influenced by Amplifier Temperature drift, improves measurement result accuracy.
Optionally, the sample circuit includes sampling resistor, and the type of the sampling resistor is four terminal resistances.
In force, the type of sample circuit is many, and typical sample circuit is sampling resistor, and sampling resistor is used to gather
The electric current of loop resistance.The sampling resistor of the present embodiment is tetra- terminal resistances of 0.75m Ω that Low Drift Temperature copper-manganese material makes, maximum
Sample rate current 100A.As shown in Fig. 2, sampling resistor R1 tools there are four output terminal, be respectively the first output terminal, second output terminal,
3rd output terminal, the 4th output terminal, input terminal of the first output terminal of sampling resistor R1 through loop resistance R2 joint test power supplys,
Another input terminal of the second output terminal joint test power supply of sampling resistor R1, the 3rd end connection voltage of sampling resistor R1 are put
The in-phase input end of big device U1, the inverting input of the 4th end connection voltage amplifier U1 of sampling resistor R1, sampling resistor R1
The analog quantity electric current of loop resistance R2 is collected by the first output terminal, second output terminal, sampling resistor R1 passes through the 3rd end,
Four ends will collect analog quantity electric current and be transmitted to voltage amplifier U1.
Optionally, the voltage amplifier have inverting input and in-phase input end, the inverting input with it is described
The sampling resistor is equipped between in-phase input end.
In force, in order to obtain the electric current of loop resistance, as described above, sampling resistor R1 is for collecting loop electricity
The analog quantity electric current of R2 is hindered, therefore, sampling resistor is equipped between the inverting input and in-phase input end of voltage amplifier U1
R1, and then voltage amplifier U1 gets analog quantity electric current, and the mould that will be got by inverting input and in-phase input end
Analog quantity electric current carries out preset multiple amplification.
Optionally, feedback resistance Rf, institute are equipped between the inverting input of the voltage amplifier and the output terminal of itself
The inverting input for stating voltage amplifier is grounded through current-limiting resistance R0.
In force, voltage amplifier U1 is in-phase voltage amplifier, and the closed loop gain of voltage amplifier U1 is by reverse phase
The decision of feedback resistance Rf and current-limiting resistance R0 is connected between input terminal and output terminal, input signal Ui is added to voltage amplifier U1
In-phase input end, the phase of output voltage Uo is identical with output signal U i, closed-loop gain A=1+Rf/R0, voltage amplification
Device to analog quantity electric current carry out preset multiple amplification so that amplified analog quantity electric current in the range of readings of A/D converter,
And then A/D converter is changed into digital quantity.Wherein, according to measurement demand, preset multiple value range is 1~1000 times.
Optionally, the instrument amplifier has in-phase input end and inverting input, the same phase of the instrument amplifier
The loop resistance is equipped between the inverting input of input terminal and the instrument amplifier.
In force, in order to obtain the analog quantity voltage of loop resistance, since instrument amplifier is different from voltage amplifier,
Instrument amplifier can directly acquire the voltage of loop resistance, therefore, in the in-phase input end and anti-phase input of instrument amplifier
End is equipped with loop resistance, and the analog quantity voltage of the loop resistance got is carried out preset multiple amplification.As shown in Fig. 2, instrument
Both ends of the in-phase input end and inverting input of table amplifier U2 respectively with loop resistance R2 are connected, the electricity of instrument amplifier U2
Press reference edge REF ground connection, the gain control end A1/A0 connection microcontrollers of instrument amplifier U2.
Wherein, instrument amplifier U2 is a special differential amplifier, has ultra-high input impedance, extremely good common
Molding ratio processed, low input offset, low output impedance can amplify those signals under common-mode voltage.It is a kind of with difference
Input and the closed loop gain component of opposite reference edge output.Two differential input ends of instrument amplifier U2 apply input signal,
Its gain by user by pin inner portions can also be set by internal preset or the outside by isolating with input signal is increased
Beneficial resistance is preset.
Optionally, at least there are two input terminals for the A/D converter.
In force, the type of A/D converter is many, the present embodiment A/D converter 16 AD7656, specific 6 A/D turn
Passage is changed, has only used two passages herein.As shown in Fig. 2, the V1 input terminals connection instrument amplifier U2's of A/D converter U3 is defeated
The output terminal of the V2 input terminals connection voltage amplifier U1 of outlet OUT, A/D converter U3, the ground connection termination of A/D converter U3
Ground, the CONVST start ends of A/D converter U3 ,/RD read control line end, DB8~DB15 data bus terminals connection microcontroller,
In, A/D converter U3 receives the amplified analog quantity voltages of instrument amplifier U2 by V1 input terminals, and A/D converter U3 will connect
The analog quantity voltage received is converted into digital quantity voltage, and reads the digital quantity voltage by microcontroller；A/D converter U3 passes through
Amplified analog quantity electric current is converted into digital quantity electricity by the amplified analog quantity electric currents of V2 input terminal receiving voltage amplifier U1
Stream makes microcontroller read digital quantity electric current.
Optionally, relay is equipped between the experiment power supply and the microcontroller.
In force, for microcontroller by controlling the startup and closing of relay Control experiment power supply, relay includes line
Circle and contact during when microcontroller so that the coil of relay and contact disconnect, and then close experiment power supply, work as microcontroller
So that when the coil and contact closure of relay, and then start experiment power supply.
Other devices with switching function are also provided between experiment power supply and microcontroller, are not gone to live in the household of one's in-laws on getting married again herein
It states.
The present invention provides the measuring circuit for measuring loop resistance, measuring circuit include experiment power supply, loop resistance,
Sample circuit, microcontroller, voltage amplifier, A/D converter, instrument amplifier.With reference to each device in above-mentioned measuring circuit
Connection relation, by using the voltage and current of dynamic zero resetting method measuring loop resistance, in the state that experiment power supply is closed,
First time measurement is carried out to the voltage and current of loop resistance, voltage and current will be got and be denoted as zero point；Start in experiment power supply
During state, second is carried out to the voltage and current of loop resistance and is measured, voltage and current will be got and subtract voltage as zero point
After electric current, itself divided by amplification factor are obtained into accurate voltage and current, and then from the influence of Amplifier Temperature drift so that it surveys
It is accurate to measure result.
Each sequence number in above-described embodiment is for illustration only, does not represent the elder generation during the assembling or use of each component
Order afterwards.
The foregoing is merely the embodiment of the present invention, are not intended to limit the invention, all in the spirit and principles in the present invention
Within, any modifications, equivalent replacements and improvements are made should all be included in the protection scope of the present invention.
Claims (7)
1. for the measuring circuit of measuring loop resistance, the measuring circuit includes experiment power supply, which is characterized in that the experiment
Loop resistance, sample circuit, microcontroller are connected on power supply, the output terminal of the loop resistance is connected with the sampling electricity
Road, the output terminal of the sample circuit are connected with voltage amplifier, and the output terminal of the voltage amplifier is connected with A/D conversions
Device, the output terminal of the A/D converter are connected with the microcontroller, and another output terminal of the loop resistance is connected with instrument
Amplifier, the output terminal of the instrument amplifier are connected with the A/D converter, and the gain control end of the instrument amplifier connects
It is connected to microcontroller.
2. the measuring circuit according to claim 1 for measuring loop resistance, which is characterized in that the sample circuit bag
Sampling resistor is included, the type of the sampling resistor is four terminal resistances.
3. the measuring circuit according to claim 2 for measuring loop resistance, which is characterized in that the voltage amplifier
The sampling electricity is equipped with inverting input and in-phase input end, between the inverting input and the in-phase input end
Resistance.
4. the measuring circuit according to claim 1 for measuring loop resistance, which is characterized in that the voltage amplifier
Inverting input and the output terminal of itself between be equipped with feedback resistance Rf, the inverting input of the voltage amplifier is through current limliting
Resistance R0 is grounded.
5. the measuring circuit according to claim 1 for measuring loop resistance, which is characterized in that the instrument amplifier
With in-phase input end and inverting input, the in-phase input end of the instrument amplifier and the reverse phase of the instrument amplifier are defeated
Enter and be equipped with the loop resistance between holding.
6. the measuring circuit according to claim 1 for measuring loop resistance, which is characterized in that the A/D converter
At least there are two input terminals.
7. the measuring circuit according to claim 1 for measuring loop resistance, which is characterized in that the experiment power supply with
Relay is equipped between the microcontroller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710934094.3A CN108051641A (en) | 2017-10-10 | 2017-10-10 | For the measuring circuit of measuring loop resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710934094.3A CN108051641A (en) | 2017-10-10 | 2017-10-10 | For the measuring circuit of measuring loop resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108051641A true CN108051641A (en) | 2018-05-18 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710934094.3A Pending CN108051641A (en) | 2017-10-10 | 2017-10-10 | For the measuring circuit of measuring loop resistance |
Country Status (1)
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| CN (1) | CN108051641A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111596133A (en) * | 2020-05-26 | 2020-08-28 | 广东电网有限责任公司东莞供电局 | GIS loop resistance testing device and method |
| CN113706128A (en) * | 2021-08-05 | 2021-11-26 | 百富计算机技术（深圳）有限公司 | Financial transaction control circuit and method and financial terminal |
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| CN1928571A (en) * | 2006-09-26 | 2007-03-14 | 华为技术有限公司 | AC voltage sampling method and system |
| CN102636680A (en) * | 2012-04-24 | 2012-08-15 | 深圳市深泰明科技有限公司 | Electric signal measurement device and storage battery floating charge current online monitoring device |
| CN102841260A (en) * | 2012-09-24 | 2012-12-26 | 哈尔滨工业大学 | DC microresistivity measuring system |
| CN202994879U (en) * | 2012-04-24 | 2013-06-12 | 深圳市深泰明科技有限公司 | Electric signal measurement device and device for on-line monitoring of storage-battery float-charging current |
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2017
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1907220A (en) * | 2006-08-16 | 2007-02-07 | 中山市创源电子有限公司 | Human body impedance measuring apparatus and fat meter using same |
| CN1928571A (en) * | 2006-09-26 | 2007-03-14 | 华为技术有限公司 | AC voltage sampling method and system |
| CN102636680A (en) * | 2012-04-24 | 2012-08-15 | 深圳市深泰明科技有限公司 | Electric signal measurement device and storage battery floating charge current online monitoring device |
| CN202994879U (en) * | 2012-04-24 | 2013-06-12 | 深圳市深泰明科技有限公司 | Electric signal measurement device and device for on-line monitoring of storage-battery float-charging current |
| CN102841260A (en) * | 2012-09-24 | 2012-12-26 | 哈尔滨工业大学 | DC microresistivity measuring system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111596133A (en) * | 2020-05-26 | 2020-08-28 | 广东电网有限责任公司东莞供电局 | GIS loop resistance testing device and method |
| CN113706128A (en) * | 2021-08-05 | 2021-11-26 | 百富计算机技术（深圳）有限公司 | Financial transaction control circuit and method and financial terminal |
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Application publication date: 20180518 |
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