CN102269775A - Low-cost and high-precision voltage measuring system and method - Google Patents
Low-cost and high-precision voltage measuring system and method Download PDFInfo
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- CN102269775A CN102269775A CN2011101255786A CN201110125578A CN102269775A CN 102269775 A CN102269775 A CN 102269775A CN 2011101255786 A CN2011101255786 A CN 2011101255786A CN 201110125578 A CN201110125578 A CN 201110125578A CN 102269775 A CN102269775 A CN 102269775A
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Abstract
The invention provides a low-cost and high-precision voltage measuring system and method. The low-cost and high-precision voltage measuring system comprises a switching circuit, a signal processing circuit, a processor and a display module; the input end of the switching circuit is connected with a measuring voltage and at least one standard voltage module; the output of the switching circuit is connected with the processor through the signal processing circuit and a control signal output end of the processor is connected with the switching circuit; and the processor is used for outputting a measuring result through the display module. In the invention, the error of the measuring voltage is only related to the standard voltage module only if the linearity error of the signal processing circuit is small enough; and the errors caused by the signal processing circuit, such as an amplifying circuit, an A/D (Analog to Digital) converter and the like, are theoretically eliminated; therefore, the aim of realizing the high-precision voltage measuring by utilizing the low-cost signal processing circuit is achieved; a standard voltage module needed by the system and the method provided by the invention exists as a standard voltage input of the A/D converter in a measuring circuit so that the increase of the cost for the module is not needed in the invention.
Description
Technical field
The present invention relates to a kind of measuring method, especially is a kind of on-line calibration method of utilizing, according to the system and method for the normal voltage calibration measurement voltage of input end, and a kind of voltage measurement method of low-cost and high-precision and adopt the measuring system of this method specifically.
Background technology
At present, the overwhelming majority is used to measure the instrument of various physical quantitys, all be to be converted into voltage signal by the signal that various sensors will need earlier to measure, again by measurement to this voltage signal, draw the value of actual measurement physical quantity, therefore the accuracy that voltage signal is measured has just directly determined the accuracy of measured magnitude of physical quantity.
Traditional measuring method all is by after the voltage signal of sensor output is handled (amplification, decay and filtering etc.), obtain meeting the magnitude of voltage of A/D converter (analog/digital signal conversion device) input range, again by the reading of A/D converter output voltage, and obtain the actual value of measured physical quantity through computing; In this process, amplifying circuit, A/D converter etc. bring error all can for the measurement of signal, and along with the variation of measures ambient temperature, these errors also can change; In order to improve the accuracy of measurement result, must use high-quality signal processing circuit (as the resistance high-accuracy, that low temperature floats, operational amplifier, and high-quality A/D converter etc.) reduces measuring error, and no matter use the how expensive treatment circuit of how accurate, price, error more or less always exists, and can't eliminate this error fully theoretically.
Summary of the invention
The objective of the invention is at instrument in the process of measure physical quantities, in order to improve precision, the signal processing circuit that must adopt expensive, high precision, low temperature to float, even if so also can't eliminate the problem of error fully, a kind of voltage measurement system and measuring method thereof of low-cost and high-precision proposed.Utilize the on-line calibration method,, eliminated the error that signal processing circuit is introduced theoretically fully, to reach purpose with the high-acruracy survey of circuit realization cheaply according to the normal voltage calibration measurement voltage of input end.
Technical scheme of the present invention:
A kind of voltage measurement system of low-cost and high-precision, it comprises switch switching circuit, signal processing circuit, processor and display module, the input termination measuring voltage of described switch switching circuit and at least one normal voltage module, the signal input part of the output termination signal processing circuit of switch switching circuit, the signal output part of signal processing circuit links to each other with processor, the control signal output ends of processor links to each other with switch switching circuit, processor links to each other with display module, display module shows measurement result as the signal output of voltage measurement system.
Switch switching circuit of the present invention comprises a plurality of switches that link to each other with the normal voltage module with measuring voltage, and an end of each switch connects measuring voltage and normal voltage module respectively, and the other end of each switch also connects, and links to each other with the signal input part of signal processing circuit.
Switch of the present invention is the contact switch of analog switch or relay, and all switches are opened by processor control or be closed.
Measuring voltage of the present invention is one or more.
Signal processing circuit of the present invention be A/D converter.
Signal processing circuit of the present invention also comprises amplifier, attenuator circuit and wave filter.
A kind of voltage measurement method of low-cost and high-precision, the voltage measurement system of application low-cost and high-precision, it comprises following three kinds of disposal routes:
(a), when the linearity error of signal processing circuit satisfies requiring of measuring accuracy, adopt two normal voltage modules;
Processor gauge tap commutation circuit switches to normal voltage 1 and normal voltage 2 successively with the input voltage x of signal processing circuit, and processor is read the output y as a result of the signal processing circuit of each input voltage correspondence, and substitution linear transmission equation y=kx+b; Processor solves the transmission coefficient k of signal processing circuit and the zero migration b of signal processing circuit, switch to measuring voltage then, read the output of corresponding measuring voltage after signal processing circuit y as a result, according to transmission equation and result y that above step obtains, processor obtains the measuring voltage value;
(b), when the linearity error of signal processing circuit satisfies requiring of measuring accuracy, and the zero migration b of signal processing circuit or transmission coefficient k are known, adopt a normal voltage module;
Processor gauge tap commutation circuit, the input voltage x of signal processing circuit is switched to normal voltage 1, processor is read through the output of signal processing circuit y as a result, and substitution linear transmission equation: y=kx+b, solve transmission coefficient k or zero migration b according to known zero migration b or transmission coefficient k; Switch to measuring voltage then, read the output of corresponding measuring voltage after signal processing circuit y as a result, according to transmission equation and result y that above step obtains, processor obtains the measuring voltage value;
(c), when the linearity error of signal processing circuit exceeds requiring of measuring accuracy, adopt a plurality of normal voltage modules;
Processor gauge tap commutation circuit, the input voltage x of signal processing circuit is switched to all normal voltage module and measuring voltage successively, read their through the output of signal processing circuit y as a result, judge from the big normal voltage module of the nearest ratio measuring voltage of measuring voltage with from the nearest little normal voltage module of ratio measuring voltage of measuring voltage according to their y, according to the voltage x of these two normal voltage modules and their through the output of signal processing circuit y as a result, substitution linear transmission equation y=kx+b; Solve transmission coefficient k and zero migration b, then according to the output of measuring voltage after signal processing circuit as a result y calculate the measuring voltage value.
Among the method a of the present invention, normal voltage 1 and normal voltage 2 are made as the upper and lower limit of voltage to be measured or near the magnitude of voltage of upper and lower limit.
Among the method b of the present invention, if the transmission coefficient k of signal processing circuit is known, then the normal voltage module is set to the lower limit of measuring voltage input or near the magnitude of voltage of lower limit; If the zero migration b of signal processing circuit is known, then the normal voltage module is set to the upper limit of measuring voltage input or near the magnitude of voltage of the upper limit; When being limited to no-voltage instantly, directly with signal ground as the standard no-voltage.
Among the method c of the present invention, a plurality of normal voltage modules are a plurality of independent standard voltage modules or are made of a normal voltage module and resistance decrement network that a described normal voltage module produces a plurality of normal voltages through the resistance decrement network.
Normal voltage module of the present invention adds amplification or attenuator circuit for voltage reference chip or the voltage reference chip of selecting for use according to the requirement of The measuring precision; Require as The measuring precision that precision is better than at 0.5% o'clock in 0 to the 70 degree scope, can select that precision is better than 0.2%, temperature is floated the voltage reference chip that is better than 20ppm for use, as ADR01AR.
Beneficial effect of the present invention:
In the present invention, as long as the linearity error of signal processing circuit is enough little (in actual the use, the employed device of signal processing circuit cheaply at last just, as resistance, operational amplifier and A/D converter etc., their linearity error all is negligible), the error of measuring voltage is just only relevant with the normal voltage module, this has just eliminated signal processing circuit theoretically, as amplifier circuit, the error that A/D converter etc. brought, thus reached the purpose that only need use signal processing circuit cheaply just can realize high-acruracy survey voltage; And needed normal voltage module among the present invention all is to import and existing as the reference voltage of A/D converter in metering circuit, and the present invention need not be that this module increases cost again.
Description of drawings
Fig. 1 is a theory diagram of the present invention.
Fig. 2 is to use the transmission curve figure of a plurality of normal voltage modules.
Fig. 3 is to use a normal voltage module and resistance decrement network to produce the synoptic diagram of a plurality of normal voltage modules.
Embodiment
The present invention is further illustrated below in conjunction with drawings and Examples.
As shown in Figure 1, a kind of voltage measurement system of low-cost and high-precision, it is characterized in that it comprises switch switching circuit, signal processing circuit, processor and display module, the input termination measuring voltage of described switch switching circuit and at least one normal voltage module, the signal input part of the output termination signal processing circuit of switch switching circuit, the signal output part of signal processing circuit links to each other with processor, the control signal output ends of processor links to each other with switch switching circuit, processor links to each other with display module, display module shows measurement result as the signal output of voltage measurement system.
Signal processing circuit of the present invention comprises A/D converter, amplifier, attenuator circuit and wave filter.The effect of signal processing circuit is measuring voltage and normal voltage process amplification or decay and filtering etc., be processed into the voltage that meets the A/D converter requirement, if measuring voltage is without any need for handling the voltage that just meets the A/D converter requirement, then amplifier, attenuator circuit and wave filter can omit.
The transmission equation of signal processing circuit is (linearity error of supposing signal processing circuit is ignored) among Fig. 1:
y?=?kx?+?b
Wherein: y---the output result of signal processing circuit;
X---input voltage;
The transmission coefficient of k---circuit;
B---zero migration;
According to the difference of measuring system accuracy requirement, this invention has following four kinds of implementations:
A, the linearity error of signal processing circuit is ignored, only need obtain the zero migration and the transmission coefficient of signal processing circuit accurately, (two normal voltage modules of needs this moment in the time of just satisfying the measuring accuracy requirement, the voltage of these two normal voltage modules be set to usually measuring voltage input on, lower limit, this disposal route is invented modal a kind of disposal route for this, because the employed device of treatment circuit cheaply at last just, its linearity error can be ignored, but its zero migration and transmission coefficient are can error bigger, and most critical is that they can change along with time and variation of temperature simultaneously):
Processor gauge tap commutation circuit switches to normal voltage 1 and normal voltage 2 successively with the input voltage x of signal processing circuit, and processor is read the output y as a result of the signal processing circuit of each input voltage correspondence, and substitution linear transmission equation y=kx+b; Processor solves the transmission coefficient k of signal processing circuit and the zero migration b of signal processing circuit, switch to measuring voltage then, read the output of corresponding measuring voltage after signal processing circuit y as a result, transmission equation that obtains according to above step and output is y as a result, and processor obtains the measuring voltage value;
When reality is used, variation along with temperature and time, the parameter of signal processing circuit itself can change (just k in the transmission equation and b can change), but as long as processor gauge tap commutation circuit switch to normal voltage again and revise k and b (this action can regularly be carried out, if processor also is connected with temperature sensor, also can carry out according to variation of temperature), just can guarantee that the value of actual measurement voltage and the variation of the parameter of circuit own have nothing to do.
The linearity error of B, signal processing circuit is ignored, only need obtain the zero migration of signal processing circuit accurately, (this moment is normal voltage module of needs only in the time of just satisfying the measuring accuracy requirement, the voltage of this normal voltage module is set to the lower limit of measuring voltage input usually, when being limited to no-voltage instantly, can be directly with signal ground as normal voltage):
Processor passes through switch switching circuit, the input voltage x of signal processing circuit is switched to normal voltage 1, the output that processor is read corresponding signal processing circuit is y as a result, and substitution linear transmission equation: y=kx+b, transmission coefficient k is according to the calculated value or the manual measurement value substitution equation of side circuit, solve b according to equation, switching input voltage x then is the measuring voltage input, the output of reading corresponding signal processing circuit is y as a result, transmission equation that obtains according to above step and output is y as a result, and processor obtains the measuring voltage value.
The linearity error of C, signal processing circuit is ignored, only need obtain the transmission coefficient of signal processing circuit accurately, in the time of just satisfying the measuring accuracy requirement (this moment is normal voltage module of needs only, and the voltage of this normal voltage module is set to the upper limit of measuring voltage input usually):
Processor passes through switch switching circuit, the input voltage x of signal processing circuit is switched to normal voltage 1, the output that processor is read corresponding signal processing circuit is y as a result, and substitution linear transmission equation: y=kx+b, zero migration b is according to the calculated value or the manual measurement value substitution equation of side circuit, solve k according to equation, switching input voltage x then is the measuring voltage input, the output of reading corresponding signal processing circuit is y as a result, transmission equation that obtains according to above step and output is y as a result, and processor obtains the measuring voltage value.
D, the linearity error of signal processing circuit can not be ignored, when just transmission equation can not be handled as a straight-line equation, can transmission curve be equally divided into multistage according to the size (relative and measuring accuracy) of linearity error, the big more segments that then needs of linearity error is many more, each segment is handled as straight line, so just need a plurality of normal voltage modules to calibrate the interior measuring voltage of each little segment limit, as Fig. 2, and these a plurality of normal voltage modules also can be directly replace by a normal voltage module and resistance decrement network, as Fig. 3):
Processor gauge tap commutation circuit, the input voltage x of signal processing circuit is switched to all normal voltage module and measuring voltage successively, read the y as a result that they are handled through signal processing circuit, judge from the big normal voltage module of the nearest ratio measuring voltage of measuring voltage with from the nearest little normal voltage module of ratio measuring voltage of measuring voltage according to their y, according to the y as a result that handle through signal processing circuit voltage x and they of these two normal voltage modules, substitution linear transmission equation y=kx+b; Solve transmission coefficient k and zero migration b, calculate the measuring voltage value according to the result y of measuring voltage after signal processing circuit then;
The part that the present invention does not relate to prior art that maybe can adopt all same as the prior art is realized.
Claims (10)
1. the voltage measurement system of a low-cost and high-precision, it is characterized in that it comprises switch switching circuit, signal processing circuit, processor and display module, the input termination measuring voltage of described switch switching circuit and at least one normal voltage module, the signal input part of the output termination signal processing circuit of switch switching circuit, the signal output part of signal processing circuit links to each other with processor, the control signal output ends of processor links to each other with switch switching circuit, processor links to each other with display module, display module shows measurement result as the signal output of voltage measurement system.
2. the voltage measurement system of low-cost and high-precision according to claim 1, it is characterized in that described switch switching circuit comprises a plurality of switches that link to each other with the normal voltage module with measuring voltage, one end of each switch connects measuring voltage and normal voltage module respectively, the other end of each switch also connects, and links to each other with the signal input part of signal processing circuit.
3. the voltage measurement system of low-cost and high-precision according to claim 1 is characterized in that described switch is the contact switch of analog switch or relay, and all switches are opened by processor control or be closed.
4. the voltage measurement system of low-cost and high-precision according to claim 1 is characterized in that described measuring voltage is one or more.
5. the voltage measurement system of low-cost and high-precision according to claim 1 is characterized in that the A/D converter that is of described signal processing circuit.
6. the voltage measurement system of low-cost and high-precision according to claim 5 is characterized in that described signal processing circuit also comprises amplifier, attenuator circuit and wave filter.
7. the voltage measurement method of a low-cost and high-precision is used the voltage measurement system of low-cost and high-precision as claimed in claim 1, it is characterized in that it comprises following three kinds of disposal routes:
(a), when the linearity error of signal processing circuit satisfies requiring of measuring accuracy, adopt two normal voltage modules;
Processor gauge tap commutation circuit switches to normal voltage 1 and normal voltage 2 successively with the input voltage x of signal processing circuit, and processor is read the output y as a result of the signal processing circuit of each input voltage correspondence, and substitution linear transmission equation y=kx+b; Processor solves the transmission coefficient k of signal processing circuit and the zero migration b of signal processing circuit, switch to measuring voltage then, read the output of corresponding measuring voltage after signal processing circuit y as a result, according to transmission equation and result y that above step obtains, processor obtains the measuring voltage value;
(b), when the linearity error of signal processing circuit satisfies requiring of measuring accuracy, and the zero migration b of signal processing circuit or transmission coefficient k are known, adopt a normal voltage module;
Processor gauge tap commutation circuit, the input voltage x of signal processing circuit is switched to normal voltage 1, processor is read through the output of signal processing circuit y as a result, and substitution linear transmission equation: y=kx+b, solve transmission coefficient k or zero migration b according to known zero migration b or transmission coefficient k; Switch to measuring voltage then, read the output of corresponding measuring voltage after signal processing circuit y as a result, according to transmission equation and result y that above step obtains, processor obtains the measuring voltage value;
(c), when the linearity error of signal processing circuit exceeds requiring of measuring accuracy, adopt a plurality of normal voltage modules;
Processor gauge tap commutation circuit, the input voltage x of signal processing circuit is switched to all normal voltage module and measuring voltage successively, read their through the output of signal processing circuit y as a result, judge from the big normal voltage module of the nearest ratio measuring voltage of measuring voltage with from the nearest little normal voltage module of ratio measuring voltage of measuring voltage according to their y, according to the voltage x of these two normal voltage modules and their through the output of signal processing circuit y as a result, substitution linear transmission equation y=kx+b; Solve transmission coefficient k and zero migration b, then according to the output of measuring voltage after signal processing circuit as a result y calculate the measuring voltage value.
8. the voltage measurement method of low-cost and high-precision according to claim 7 is characterized in that among the described method a, and normal voltage 1 and normal voltage 2 are made as the upper and lower limit of voltage to be measured or near the magnitude of voltage of upper and lower limit.
9. the voltage measurement method of low-cost and high-precision according to claim 7, it is characterized in that among the described method b, if the transmission coefficient k of signal processing circuit is known, then the normal voltage module is set to the lower limit of measuring voltage input or near the magnitude of voltage of lower limit; If the zero migration b of signal processing circuit is known, then the normal voltage module is set to the upper limit of measuring voltage input or near the magnitude of voltage of the upper limit; When being limited to no-voltage instantly, directly with signal ground as the standard no-voltage.
10. the voltage measurement method of low-cost and high-precision according to claim 7, it is characterized in that among the described method c, a plurality of normal voltage modules are a plurality of independent standard voltage modules or are made of a normal voltage module and resistance decrement network that a described normal voltage module produces a plurality of normal voltages through the resistance decrement network.
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| CN2011101255786A CN102269775A (en) | 2011-05-16 | 2011-05-16 | Low-cost and high-precision voltage measuring system and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487639A (en) * | 2012-06-07 | 2014-01-01 | 亚旭电脑股份有限公司 | Current measuring system |
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| CN1376911A (en) * | 2001-03-27 | 2002-10-30 | 湘潭工学院 | Analysis linearizing and automatic heat capacity compensating method for intelligent calorimeter |
| US20050007802A1 (en) * | 2003-04-11 | 2005-01-13 | Gerpheide George E. | Zero drift analog memory cell, array and method of operation |
| CN1614440A (en) * | 2003-11-07 | 2005-05-11 | 上海燃料电池汽车动力系统有限公司 | Voltage measuring circuit of single accumulator |
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2011
- 2011-05-16 CN CN2011101255786A patent/CN102269775A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US5121051A (en) * | 1988-09-22 | 1992-06-09 | U.S. Philips Corporation | Method and apparatus for measuring small electrical signals |
| CN1376911A (en) * | 2001-03-27 | 2002-10-30 | 湘潭工学院 | Analysis linearizing and automatic heat capacity compensating method for intelligent calorimeter |
| US20050007802A1 (en) * | 2003-04-11 | 2005-01-13 | Gerpheide George E. | Zero drift analog memory cell, array and method of operation |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103487639A (en) * | 2012-06-07 | 2014-01-01 | 亚旭电脑股份有限公司 | Current measuring system |
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Application publication date: 20111207 |