CN209485564U - It is a kind of to correct the nonlinear temperature transmitter of platinum resistance using negative resistance - Google Patents
It is a kind of to correct the nonlinear temperature transmitter of platinum resistance using negative resistance Download PDFInfo
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- CN209485564U CN209485564U CN201920518232.4U CN201920518232U CN209485564U CN 209485564 U CN209485564 U CN 209485564U CN 201920518232 U CN201920518232 U CN 201920518232U CN 209485564 U CN209485564 U CN 209485564U
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Abstract
The utility model belongs to detection field, and in particular to a kind of to correct the nonlinear temperature transmitter of platinum resistance using negative resistance.Transmitter is made of constant-current source circuit, equivalent negative resistance circuit, the differential amplifier circuit of high cmrr, differential amplifier circuit, output driving circuit and the D.C. regulated power supply that gain is 1.In the lower limit of dut temperature, adjusting RP2 makes the electric current 4mA on recipient；In the upper limit of dut temperature, adjusting RP1 makes the electric current 20mA on recipient；When normal thermometric, the pick-up output electric current for flowing through load resistance RL is 4~20mA.The utility model can not only improve the measurement accuracy of temperature signal, and be suitable for remote transmission.
Description
Technical field
The utility model belongs to detection field, is related to a kind of utilization negative resistance correction nonlinear 4~20mA temperature of platinum resistance
Spend transmitter.
Background technique
Temperature measurement and control accounts for sizable specific gravity in industrial application, it is mainly by temperature sensor, connecting cable
(to remote transmission), temperature display and control device form.In most cases, temperature sensor is very severe, noisy
It works in environment, measuring instrument will be far from sensor, and transmission line actually required is very long.When with voltage signal transmission it is longer away from
From when, vulnerable to electromagnetic noise interference；If being transmitted with current signal, not vulnerable to the influence of length of transmission line.4~20mA electric current becomes
The function of sending device interface is exactly that the output of sensor is converted to electric current to be transferred to load, improves the remote transmission of measured signal
Ability.
Platinum resistance temperature sensor has many advantages, such as that stability is good, temperature range is wide, anti-vibration, shock resistance, examines in temperature
It is widely used in examining system.Within the scope of 0~850 DEG C, platinum resistance value variation with temperature and non-linear relation influence platinum resistance
The precision of temperature detection.In 0~850 DEG C of temperature range, non-linear is about 2.7%.
In order to carry out linearity correction to platinum resistance, and the remote transmittability of temperature signal is improved, develops linearisation
Platinum resistance current transducer has important practical value.
The utility model carries out gamma correction to platinum resistance using equivalent negative resistance, and temperature transmitter can not only improve
The measurement accuracy of temperature signal, and it is suitable for remote transmission.
Utility model content
The technical scheme adopted by the utility model is
Temperature transmitter is by constant-current source circuit, equivalent negative resistance circuit, the differential amplifier circuit of high cmrr, increasing
Benefit is constituted for 1 differential amplifier circuit, output driving circuit and D.C. regulated power supply；
D.C. regulated power supply is 24VDC, anode VDD, negative terminal VSS；
Constant-current source circuit is made of REF200 chip, the anode VDD phase of REF200 chip input terminal and D.C. regulated power supply
Connection, REF200 chip export the 100 constant micro-currents of μ A to equivalent negative resistance circuit；
Equivalent negative resistance circuit is by amplifier IC0, positive temperature coefficient resistor RJ, resistance R10=10K Ω and resistance R11=10K
Ω composition, amplifier IC0 select high precision operating amplifier OP07；Two ends of positive temperature coefficient resistor RJ couple amplifier IC0 respectively
Positive input terminal and output end, two ends of resistance R10 couple amplifier IC0 negative input end and output end, bis- end resistance R11 difference respectively
Connection amplifier IC0 output end and D.C. regulated power supply negative terminal VSS, amplifier IC0 output end are connected with REF200 chip output；
The differential amplifier circuit of high cmrr by amplifier IC1, amplifier IC2, adjust full scale potentiometer RP1=10K Ω,
Zero potentiometer RP2=10K Ω, feedback resistance R1=10K Ω, feedback resistance R2=10K Ω, resistance R3=10K Ω, resistance R4
=10K Ω, resistance R5=10K Ω and testing temperature thermal resistance RTD composition, amplifier IC1 and amplifier IC2 select high-accuracy arithmetic amplification
Device OP07；Two ends of feedback resistance R1 couple amplifier IC1 negative input end and output end respectively, and two ends of feedback resistance R2 join respectively
Connect amplifier IC2 negative input end and output end；Two fixing ends of full scale potentiometer RP1 are adjusted to couple amplifier IC1 negative input end respectively
With amplifier IC2 negative input end, the adjustable end of full scale potentiometer RP1 is adjusted to be connected with a fixing end；Bis- end testing temperature thermal resistance RTD
Couple amplifier IC1 positive input terminal and amplifier IC2 positive input terminal respectively；Two fixing ends of zero potentiometer RP2 couple electricity respectively
One end of R3 and one end of resistance R4 are hindered, the other end of resistance R3 and the anode VDD of D.C. regulated power supply are connected, and resistance R4's is another
The negative terminal VSS of one end and D.C. regulated power supply is connected；One end of resistance R5 is connected with amplifier IC2 negative input end, and resistance R5 is another
It holds and is connected with the adjustable end of potentiometer RP2；The positive input terminal and amplifier IC1 positive input terminal of the amplifier IC0 of equivalent negative resistance circuit
It is connected, amplifier IC2 positive input terminal is connected with D.C. regulated power supply negative terminal VSS；
The differential amplifier that gain is 1 is by amplifier IC3, input resistance R6=10K Ω, input resistance R7=10K Ω, feedback
Resistance R8=10K Ω, feedback resistance R9=10K Ω composition, amplifier IC3 select high precision operating amplifier OP07；Input resistance
Bis- end R7 couples amplifier IC1 output end and amplifier IC3 positive input terminal respectively, and it is defeated that bis- end input resistance R7 couples amplifier IC2 respectively
Outlet and amplifier IC3 negative input end；
Output driving circuit is by driving triode Q, resistance R12=1K Ω, resistance R13=150 Ω, resistance R14=150
Ω, capacitor C1=0.1 μ F, capacitor C2=0.1 μ F and load resistance RL composition, driving triode Q model 9013；Resistance R12
Two ends couple the end b of driving triode Q and the end e of driving triode Q, the end c of driving triode Q and D.C. regulated power supply respectively
Anode VDD be connected, amplifier IC3 output end and the end b of driving triode Q are connected；Capacitor C1, capacitor C2 and resistance R13, resistance
R14 series connection, the other end of capacitor C1 and the anode VDD of D.C. regulated power supply be connected, and capacitor C1 and capacitor C2 are connected place and direct current
Regulated power supply negative terminal VSS is connected；Resistance R13 and the resistance place of being connected R14 and the end e of driving triode Q are connected, and resistance R14's is another
One end is connected with feedback resistance R8, and the feedback resistance R8 other end is connected with amplifier IC3 negative input end；Capacitor C2 and resistance R13 phase
It is connected at connection with feedback resistance R9, the feedback resistance R9 other end is connected with amplifier IC3 positive input terminal；The one end load resistance RL passes through
Long connecting line is connected with D.C. regulated power supply negative terminal VSS, the one end load resistance RL by long connecting line and another capacitor C2 and
The place of being connected resistance R13 is connected；
In the lower limit of dut temperature, adjusting RP2 makes the electric current 4mA on load RL；In the upper limit of dut temperature, adjust
RP1 makes the electric current 20mA on load RL；When normal thermometric, the pick-up output electric current for flowing through load resistance RL is 4~20mA.
The beneficial effects of the utility model are: the nonlinear temperature transmitter of platinum resistance is corrected using negative resistance, it can not only
The measurement accuracy of temperature signal is improved, and is suitable for remote transmission.
Detailed description of the invention
Attached drawing 1 is a kind of utilization negative resistance correction nonlinear temperature transmitter line map of platinum resistance.
Specific embodiment
The specific embodiment of utility model device is described further with reference to the accompanying drawing.
According to platinum resistance RTD within the scope of 0~850 DEG C, the relational expression Rt=R0 (1+at+bt of temperature and impedance2), it draws
The relation curve of voltage in the case of constant value exciting current on RTD and temperature out, it finds that as the temperature rises, voltage base
Linearly increasing in sheet, only curve is somewhat sagging slightly.If the electric current of RTD is flowed through in appropriate increase, this as temperature increases
It is sagging to mitigate, it is non-linear also to reduce.Can play the role of improving just to a RTD negative resistance in parallel it is nonlinear,
This is because negative resistance both end voltage is higher, the electric current for flowing through negative resistance will be smaller, then flows through RTD's under constant value current excitation
Electric current is increase accordingly.One positive resistance RJ is placed on the output end of amplifier IC0 to positive input terminal by circuit shown in 1 dotted line frame of attached drawing
Feedback loop on, circuit characteristic is equivalent to the resistance an of-RJ.Chip REF200 is RTD and negative resistance connected in parallel
The constant value exciting current of 100 μ A is provided.Suitable negative electricity resistance value is chosen, non-linear will be corrected well of RTD response is non-
Linearly it can be reduced to about 0.08% from about 2.7%, improve more than 30 times, and temperature range is smaller, improvement is just more obvious.
The value of required negative resistance depends on interested temperature range, and the value for accurately calculating resistance RJ is difficult, below
Empirical equation can obtain preferable calibration result.
RJ=R0 × (27.3-0.00455 × T1-0.0057 × T2), 850 DEG C > T2 > T1 > 0 DEG C
In formula, the resistance value of RTD when R0 is 0 DEG C, unit is Ω.；T1 and T2 is the upper limit of dut temperature range respectively under
Limit, unit is DEG C.Such as to Pt1000, in 0~850 DEG C of temperature range, RJ=22.46K Ω.
To guarantee to remain to reach good performance when using very long transmission line, should be matched between all similar resistance resistance
Well；Plus capacitor C1 and C2 to prevent from vibrating between power supply and output end.
It should be calibrated using the transmission line actually connected when debugging, in the lower limit of dut temperature, adjusting RP2 makes loading
Electric current on RL is 4mA；In the upper limit of dut temperature, adjusting RP1 makes the electric current 20mA on load RL.Temperature transmitter pair
Pt1000 carries out thermometric experiment within the scope of 0~850 DEG C, the results showed that, the above-mentioned transmitter with nonlinear compensation, temperature test
Precision is better than 1%.
Above-described is only preferred embodiments of the present invention, and the utility model is not limited to above embodiments.It can
To understand, what those skilled in the art directly exported or associated under the premise of not departing from the spirit and design of the utility model
Oher improvements and changes are considered as being included within the scope of protection of this utility model.
Claims (1)
1. a kind of correct the nonlinear temperature transmitter of platinum resistance using negative resistance, which is characterized in that temperature transmitter is by constant current
Source circuit, equivalent negative resistance circuit, the differential amplifier circuit of high cmrr, the differential amplifier circuit, defeated that gain is 1
Driving circuit and D.C. regulated power supply are constituted out；
D.C. regulated power supply is 24VDC, anode VDD, negative terminal VSS；
Constant-current source circuit is made of REF200 chip, and the anode VDD of REF200 chip input terminal and D.C. regulated power supply is connected,
REF200 chip exports the 100 constant micro-currents of μ A to equivalent negative resistance circuit；
Equivalent negative resistance circuit is by amplifier IC0, positive temperature coefficient resistor RJ, resistance R10=10K Ω and resistance R11=10K Ω group
At amplifier IC0 selects high precision operating amplifier OP07；It is just defeated that two ends of positive temperature coefficient resistor RJ couple amplifier IC0 respectively
Enter end and output end, two ends of resistance R10 couple amplifier IC0 negative input end and output end respectively, and bis- end resistance R11 couples respectively
Amplifier IC0 output end and D.C. regulated power supply negative terminal VSS, amplifier IC0 output end are connected with REF200 chip output；
The differential amplifier circuit of high cmrr is by amplifier IC1, amplifier IC2, tune full scale potentiometer RP1=10K Ω, zeroing
Potentiometer RP2=10K Ω, feedback resistance R1=10K Ω, feedback resistance R2=10K Ω, resistance R3=10K Ω, resistance R4=
10K Ω, resistance R5=10K Ω and testing temperature thermal resistance RTD composition, amplifier IC1 and amplifier IC2 select high precision operating amplifier
OP07；Two ends of feedback resistance R1 couple amplifier IC1 negative input end and output end respectively, and two ends of feedback resistance R2 couple respectively
Amplifier IC2 negative input end and output end；Adjust full scale potentiometer RP1 two fixing ends couple respectively amplifier IC1 negative input end and
Amplifier IC2 negative input end adjusts the adjustable end of full scale potentiometer RP1 to be connected with a fixing end；Bis- end testing temperature thermal resistance RTD point
It Lian Jie not amplifier IC1 positive input terminal and amplifier IC2 positive input terminal；Two fixing ends of zero potentiometer RP2 distinguish connection electrical resistance
One end of R3 and one end of resistance R4, the other end of resistance R3 and the anode VDD of D.C. regulated power supply are connected, and resistance R4's is another
It holds and is connected with the negative terminal VSS of D.C. regulated power supply；One end of resistance R5 is connected with amplifier IC2 negative input end, the resistance R5 other end
It is connected with the adjustable end of potentiometer RP2；The positive input terminal of the amplifier IC0 of equivalent negative resistance circuit and amplifier IC1 positive input terminal phase
Connection, amplifier IC2 positive input terminal are connected with D.C. regulated power supply negative terminal VSS；
The differential amplifier that gain is 1 is by amplifier IC3, input resistance R6=10K Ω, input resistance R7=10K Ω, feedback resistance
R8=10K Ω, feedback resistance R9=10K Ω composition, amplifier IC3 select high precision operating amplifier OP07；Input resistance R7 bis-
End couples amplifier IC1 output end respectively and amplifier IC3 positive input terminal, bis- end input resistance R7 couple amplifier IC2 output end respectively
With amplifier IC3 negative input end；
Output driving circuit is by driving triode Q, resistance R12=1K Ω, resistance R13=150 Ω, resistance R14=150 Ω, electricity
Hold C1=0.1 μ F, capacitor C2=0.1 μ F and load resistance RL composition, driving triode Q model 9013；Bis- end resistance R12 point
Not Lian Jie the end b of driving triode Q and the end e of driving triode Q, the end c of driving triode Q and the anode of D.C. regulated power supply
VDD is connected, and amplifier IC3 output end and the end b of driving triode Q are connected；Capacitor C1, capacitor C2 and resistance R13, resistance R14 string
Connection, the other end of capacitor C1 and the anode VDD of D.C. regulated power supply be connected, and capacitor C1 and capacitor C2 are connected place and DC voltage-stabilizing electricity
Source negative terminal VSS is connected；Resistance R13 and the resistance place of being connected R14 and the end e of driving triode Q are connected, the other end of resistance R14 with
Feedback resistance R8 is connected, and the feedback resistance R8 other end is connected with amplifier IC3 negative input end；Capacitor C2 and resistance R13 be connected place with
Feedback resistance R9 is connected, and the feedback resistance R9 other end is connected with amplifier IC3 positive input terminal；The one end load resistance RL passes through long company
Wiring is connected with D.C. regulated power supply negative terminal VSS, and the one end load resistance RL passes through long connecting line and another capacitor C2 and resistance R13
The place of being connected is connected；
In the lower limit of dut temperature, adjusting RP2 makes the electric current 4mA on load RL；In the upper limit of dut temperature, RP1 is adjusted
Make the electric current 20mA on load RL；When normal thermometric, the pick-up output electric current for flowing through load resistance RL is 4~20mA.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920518232.4U CN209485564U (en) | 2019-04-17 | 2019-04-17 | It is a kind of to correct the nonlinear temperature transmitter of platinum resistance using negative resistance |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920518232.4U CN209485564U (en) | 2019-04-17 | 2019-04-17 | It is a kind of to correct the nonlinear temperature transmitter of platinum resistance using negative resistance |
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| Publication Number | Publication Date |
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| CN209485564U true CN209485564U (en) | 2019-10-11 |
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| CN201920518232.4U Expired - Fee Related CN209485564U (en) | 2019-04-17 | 2019-04-17 | It is a kind of to correct the nonlinear temperature transmitter of platinum resistance using negative resistance |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111238673A (en) * | 2020-01-06 | 2020-06-05 | 宁波中车时代传感技术有限公司 | Measuring circuit of film temperature sensor |
-
2019
- 2019-04-17 CN CN201920518232.4U patent/CN209485564U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111238673A (en) * | 2020-01-06 | 2020-06-05 | 宁波中车时代传感技术有限公司 | Measuring circuit of film temperature sensor |
| WO2021139128A1 (en) * | 2020-01-06 | 2021-07-15 | 宁波中车时代传感技术有限公司 | Measurement circuit of thin-film temperature sensor |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20191011 Termination date: 20200417 |
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| CF01 | Termination of patent right due to non-payment of annual fee |