CN203241168U - Platinum resistor non-linear correction temperature transmitter - Google Patents
Platinum resistor non-linear correction temperature transmitter Download PDFInfo
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- CN203241168U CN203241168U CN 201320213248 CN201320213248U CN203241168U CN 203241168 U CN203241168 U CN 203241168U CN 201320213248 CN201320213248 CN 201320213248 CN 201320213248 U CN201320213248 U CN 201320213248U CN 203241168 U CN203241168 U CN 203241168U
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- temperature
- bridge
- gain amplifier
- programmable gain
- linear correction
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Abstract
The utility model relates to a platinum resistor non-linear correction temperature transmitter, comprising a temperature measurement electrical bridge and a programmable gain amplifier GPA, wherein a power supply negative terminal of the temperature measurement electrical bridge is connected with a signal ground through a common-mode coupling resistor Rc; an output terminal of the temperature measurement electrical bridge is connected with an input terminal of the programmable gain amplifier GPA; a non-linear compensation resistor Rf is connected between an input positive terminal and an output terminal of the programmable gain amplifier GPA to form positive feedback; and the temperature measurement electrical bridge is a Wheatstone bridge taking a platinum resistor TR as an arm of a bridge circuit. The platinum resistor non-linear correction temperature transmitter adopts the common-mode coupling resistor and the non-linear compensation resistor and converts the platinum resistor's resistance value, which changes along with the temperature, into voltage signals through the temperature measurement electrical bridge and the programmable gain amplifier. The platinum resistor non-linear correction temperature transmitter employs a hardware linear correction method and adopts digital zero and full scale adjustment, thereby preventing the defects of debugging error and poor stability caused by a potentiometer or a resistor and realizing low-cost high-precision temperature measurement.
Description
Technical field
The utility model relates to detection technique and automatic control technology field, specifically, relates to a kind of temperature transmission circuit.
Background technology
Temperature relates to an important physical amount of industrial and agricultural production, scientific research, environmental protection, meteorology and even daily life, how to realize measuring accurately tool and has very important significance.Especially for the temperature instrumentation of process industrial, require especially temperature measurement accuracy height, good reliability, but also the low characteristics of cost will be arranged.
Temperature transmitter in the past all adopts analogue technique and singlechip technology to realize, adopt the temperature transmitter of analogue technique, although cost is not high, but owing to be to use potentiometer (or resistor) to adjust zero-bit and full scale, therefore be difficult to the adjustment accuracy that reaches high, and potentiometer can drift about in time, and reliability and stability are all bad, and the result who directly brings is that measuring accuracy is difficult to improve; Adopt the temperature transmitter of singlechip technology to carry out non-linear correction with software, the software adjustment of zero-bit and full scale, measuring accuracy is high, good reliability, but cost is higher, is unfavorable for batch production, and application is restricted.
At present, platinum resistance is temperature sensor the most frequently used in the industrial processes.Therefore the characteristics such as platinum resistance has that measurement range is wide, precision is high, good stability and resistance to oxidation, have obtained using very widely at middle low-temperature space.
The formula that the temperature variant relation of platinum resistance is deferred to is:
R
t=R
0[1+A
t+Bt
2+Ct
3(t-100)] -200℃～0℃
R
t=R
0(1+At+Bt
2) 0℃～600℃
In the formula,
R
tBe the resistance value of platinum resistance element when the temperature t;
R
0Be the resistance value of platinum resistance element 0 ℃ the time;
A, B, C are the calibration constant;
T is the measured medium temperature.
This shows between the resistance of platinum resistance and the temperature and have nonlinear relationship, in the application process of platinum sensor, usually utilize unbalance bridge circuit that the resistance variations of platinum sensor is changed into voltage, after platinum resistance access bridge for measuring temperature circuit, owing to have nonlinear relationship between arm resistance and the bridge output voltage, the voltage of electric bridge output and the nonlinear degree of temperature also can strengthen, and the non-linear and uneven bridge for measuring temperature unintentional nonlinearity of platinum resistance is brought very large nonlinearity erron to temperature survey.Therefore, be necessary it is carried out non-linear correction.
The utility model content
Large, the problems referred to above such as precision is low, poor stability of nonlinearity erron that the utility model exists during for existing temperature transmitter thermometric provide that a kind of nonlinearity erron is little, measuring accuracy is high, good stability, the non-linear correction temperature of platinum resistance transmission circuit that cost is low.
The technical solution of the utility model: the non-linear correction temperature of a kind of platinum resistance transmission circuit, comprise bridge for measuring temperature and programmable gain amplifier PGA, the power supply negative terminal of bridge for measuring temperature is connected with signal ground by common mode build-out resistor Rc, the output terminal of bridge for measuring temperature is connected with the input end of programmable gain amplifier PGA, be connected to the nonlinear compensation resistance R _ f between the input anode of programmable gain amplifier PGA and its output terminal, form positive feedback; Bridge for measuring temperature is by the wheatstone bridge of platinum resistance RT as bridge circuit one arm.
Preferably, described temperature transmission circuit also comprises the V/I change-over circuit, and the power supply of bridge for measuring temperature is just terminating at the reference voltage terminal of V/I change-over circuit, and the output terminal of programmable gain amplifier PGA is connected with the input end of V/I change-over circuit.
Preferably, described temperature transmission circuit also comprises excitation voltage source Vr, and excitation voltage source Vr is connected on the power supply anode of bridge for measuring temperature.
Preferably, described platinum resistance RT adopts two-wire system or three-wire system platinum resistance.
Preferably, programmable gain amplifier PGA adopts the programmable gain amplifier of adjustable zero position, full scale.
The beneficial effects of the utility model: the utility model utilizes the method for hardware linear revise, adjusts zero-bit and full scale with numeral, has avoided debugging error that potentiometer or resistance brings and the shortcoming of poor stability, has realized low-cost, high-precision temperature survey; Bridge for measuring temperature power supply negative terminal is connected with signal ground by common mode build-out resistor Rc, the signal that makes programmable gain amplifier be used for temperature detecting resistance amplifies and becomes possibility, and be connected to the nonlinear compensation resistance R _ f between the input anode of programmable gain amplifier and its output terminal, temperature variant resistance value nonlinearities change signal amplifies through programmable gain amplifier, the part of its output feeds back to the input anode of programmable gain amplifier through the nonlinear compensation resistance R _ f, again with the rear non-linear correction that realizes temperature detecting resistance of temperature detecting resistance signal stack, as long as the range of temperature detecting resistance is determined, just can see whether the error of range mid point output signal is minimum by zeroing position and full scale, determine the size of compensating resistance, namely in the situation of other parameter constants, nonlinear compensation resistance is only relevant with range, be easy to batch production, can accomplish nonlinearity erron≤0.025%FS.Temperature detecting resistance refers to the resistor of positive temperature coefficient (PTC).The utility model adopts platinum resistance as temperature detecting resistance, can realize low cost, high-precision temperature survey in the temperature-measuring range of platinum resistance.
Description of drawings
Accompanying drawing 1 is the circuit theory diagrams of the utility model embodiment one.
Accompanying drawing 2 is the circuit theory diagrams of the utility model embodiment two.
Embodiment
The utility model is described in further detail below in conjunction with accompanying drawing.
Embodiment 1: as shown in Figure 1, the non-linear correction temperature of a kind of platinum resistance transmission circuit, comprise bridge for measuring temperature, programmable gain amplifier PGA and V/I change-over circuit, the power supply of bridge for measuring temperature is just terminating at the reference voltage terminal of V/I change-over circuit, be bridge for measuring temperature power supply by the V/I change-over circuit, the power supply negative terminal of bridge for measuring temperature is connected with signal ground by common mode build-out resistor Rc, the signal that makes programmable gain amplifier PGA be used for temperature detecting resistance amplifies and becomes possibility, the output terminal of bridge for measuring temperature is connected with the input end of programmable gain amplifier PGA, and the output terminal of programmable gain amplifier PGA is connected with the input end of V/I change-over circuit; Be connected to the nonlinear compensation resistance R _ f between the input anode of programmable gain amplifier PGA and its output terminal, form positive feedback, realized the nonlinear compensation function.Bridge for measuring temperature is by the wheatstone bridge of platinum resistance RT as bridge circuit one arm, adopts platinum resistance RT as temperature detecting resistance, has realized low-cost, high-precision temperature survey in the temperature-measuring range of platinum resistance.
Above-mentioned platinum resistance RT adopts two-wire system or three-wire system platinum resistance.
Programmable gain amplifier PGA is when realizing that signal to platinum resistance RT amplifies, and in order to realize the numeral adjustment of zero-bit and full scale, above-mentioned programmable gain amplifier PGA adopts the programmable gain amplifier of adjustable zero position, full scale.
The output current of above-mentioned V/I change-over circuit is 4mA-20mA.
The resistance value of common mode build-out resistor Rc sees by adjusting zero-bit, full scale whether the output signal of programmable gain amplifier PGA is normally selected, and its resistance value is greater than critical value usually.
The resistance value of nonlinear compensation resistance R _ f sees by adjusting zero-bit, full scale whether the signal errors value of range mid point is minimum next definite, and resistance value at this moment is the nonlinear compensation resistance value under this range.
Adopt the non-linear correction temperature transmitter of platinum resistance of the non-linear correction temperature of present embodiment platinum resistance transmission circuit, in 0 ℃ of-100 ℃ of scope, replace the result of platinum resistance test with resistance box, its maximum error≤0.025%FS.
The non-linear correction temperature of present embodiment platinum resistance transmission circuit is applicable to the current output type temperature transmitter.
Principle of work: the V/I change-over circuit is the bridge for measuring temperature power supply, make programmable gain amplifier PGA realize the non-linear correction of platinum resistance RT thermometric by common mode build-out resistor Rc, the signal of the temperature variant resistance value nonlinearities change of platinum resistance RT amplifies through programmable gain amplifier PGA, a part of nonlinear properties of programmable gain amplifier PGA output feed back to the input anode of programmable gain amplifier PGA through the nonlinear compensation resistance R _ f, realize the non-linear correction of platinum resistance RT again with after the stack of platinum resistance RT signal.
Embodiment 2: as shown in Figure 2, the non-linear correction temperature of a kind of platinum resistance transmission circuit, comprise bridge for measuring temperature, programmable gain amplifier PGA and excitation voltage source, the power supply anode of bridge for measuring temperature is connected with excitation voltage source, be bridge for measuring temperature power supply by excitation voltage source, the power supply negative terminal of bridge for measuring temperature is connected with signal ground by common mode build-out resistor Rc, the signal that makes programmable gain amplifier PGA be used for temperature detecting resistance amplifies and becomes possibility, and the output terminal of bridge for measuring temperature is connected with the input end of programmable gain amplifier PGA; Be connected to the nonlinear compensation resistance R _ f between the input anode of programmable gain amplifier PGA and its output terminal, form positive feedback, realized the nonlinear compensation function.Bridge for measuring temperature is by the wheatstone bridge of platinum resistance RT as bridge circuit one arm, adopts platinum resistance RT as temperature detecting resistance, has realized low-cost, high-precision temperature survey in the temperature-measuring range of platinum resistance.
Above-mentioned platinum resistance RT adopts two-wire system or three-wire system platinum resistance.
Programmable gain amplifier PGA is when realizing that signal to platinum resistance RT amplifies, and in order to realize the numeral adjustment of zero-bit and full scale, above-mentioned programmable gain amplifier PGA adopts the programmable gain amplifier of adjustable zero position, full scale.
The resistance value of common mode build-out resistor Rc sees by adjusting zero-bit, full scale whether the output signal of programmable gain amplifier PGA is normally selected, and its resistance value is greater than critical value usually.
The resistance value of nonlinear compensation resistance R _ f sees by adjusting zero-bit, full scale whether the signal errors value of range mid point is minimum next definite, and resistance value at this moment is the nonlinear compensation resistance value under this range.
Adopt the non-linear correction temperature transmitter of platinum resistance of the non-linear correction temperature of present embodiment platinum resistance transmission circuit, in 0 ℃ of-100 ℃ of scope, replace the result of platinum resistance test with resistance box, its maximum error≤0.025%FS.
The non-linear correction temperature of present embodiment platinum resistance transmission circuit is applicable to output voltage type temperature transmitter.
Principle of work: excitation voltage source is the bridge for measuring temperature power supply, make programmable gain amplifier PGA realize the non-linear correction of platinum resistance RT thermometric by common mode build-out resistor Rc, the signal of the temperature variant resistance value nonlinearities change of platinum resistance RT amplifies through programmable gain amplifier PGA, a part of nonlinear properties of programmable gain amplifier PGA output feed back to the input anode of programmable gain amplifier PGA through the nonlinear compensation resistance R _ f, realize the non-linear correction of platinum resistance RT again with after the stack of platinum resistance RT signal.
More than be ultimate principle of the present utility model and feature; the utility model embodiment can not only limit to this; technician for the industry; under the prerequisite that does not break away from the utility model thinking; also can make other similar changes, and this all should be considered as the desired protection domain of the utility model claims.
Claims (5)
1. the non-linear correction temperature of platinum resistance transmission circuit, it is characterized in that: comprise bridge for measuring temperature and programmable gain amplifier PGA, the power supply negative terminal of bridge for measuring temperature is connected with signal ground by common mode build-out resistor Rc, the output terminal of bridge for measuring temperature is connected with the input end of programmable gain amplifier PGA, be connected to the nonlinear compensation resistance R _ f between the input anode of programmable gain amplifier PGA and its output terminal, form positive feedback; Bridge for measuring temperature is by the wheatstone bridge of platinum resistance RT as bridge circuit one arm.
2. the non-linear correction temperature of platinum resistance according to claim 1 transmission circuit, it is characterized in that: described temperature transmission circuit also comprises the V/I change-over circuit, the power supply of bridge for measuring temperature is just terminating at the reference voltage terminal of V/I change-over circuit, and the output terminal of programmable gain amplifier PGA is connected with the input end of V/I change-over circuit.
3. the non-linear correction temperature of platinum resistance according to claim 1 transmission circuit, it is characterized in that: described temperature transmission circuit also comprises excitation voltage source Vr, excitation voltage source Vr is connected on the power supply anode of bridge for measuring temperature.
4. the non-linear correction temperature of platinum resistance according to claim 1 transmission circuit is characterized in that: described platinum resistance RT employing two-wire system or three-wire system platinum resistance.
5. the non-linear correction temperature of platinum resistance according to claim 1 transmission circuit is characterized in that: the programmable gain amplifier of described programmable gain amplifier PGA employing adjustable zero position, full scale.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320213248 CN203241168U (en) | 2013-04-24 | 2013-04-24 | Platinum resistor non-linear correction temperature transmitter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320213248 CN203241168U (en) | 2013-04-24 | 2013-04-24 | Platinum resistor non-linear correction temperature transmitter |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103278257A (en) * | 2013-04-24 | 2013-09-04 | 青岛航天半导体研究所有限公司 | Non-linear platinum resistor correction temperature transmission circuit |
| CN104296919A (en) * | 2014-09-15 | 2015-01-21 | 青岛航天半导体研究所有限公司 | Nonlinear compensating circuit of resistance bridge type sensor |
| CN107063495A (en) * | 2016-11-28 | 2017-08-18 | 科诺伟业风能设备（北京）有限公司 | Two-wire system PT100 resistance and the compatible temperature measurement circuit of NTC resistance |
| CN109443488A (en) * | 2018-10-31 | 2019-03-08 | 四川泛华航空仪表电器有限公司 | A kind of high-precision fuel quantity measurement method with temperature-compensating |
-
2013
- 2013-04-24 CN CN 201320213248 patent/CN203241168U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103278257A (en) * | 2013-04-24 | 2013-09-04 | 青岛航天半导体研究所有限公司 | Non-linear platinum resistor correction temperature transmission circuit |
| CN103278257B (en) * | 2013-04-24 | 2017-04-12 | 青岛航天半导体研究所有限公司 | Non-linear platinum resistor correction temperature transmission circuit |
| CN104296919A (en) * | 2014-09-15 | 2015-01-21 | 青岛航天半导体研究所有限公司 | Nonlinear compensating circuit of resistance bridge type sensor |
| CN104296919B (en) * | 2014-09-15 | 2017-07-11 | 青岛航天半导体研究所有限公司 | A kind of non-linear compensation circuit of resistance bridge type sensor |
| CN107063495A (en) * | 2016-11-28 | 2017-08-18 | 科诺伟业风能设备（北京）有限公司 | Two-wire system PT100 resistance and the compatible temperature measurement circuit of NTC resistance |
| CN109443488A (en) * | 2018-10-31 | 2019-03-08 | 四川泛华航空仪表电器有限公司 | A kind of high-precision fuel quantity measurement method with temperature-compensating |
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Legal Events
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131016 Termination date: 20150424 |
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| EXPY | Termination of patent right or utility model |