CN205861236U - Novel platinum thermal resistance sensor temperature collection circuit - Google Patents
Novel platinum thermal resistance sensor temperature collection circuit Download PDFInfo
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- CN205861236U CN205861236U CN201620760431.2U CN201620760431U CN205861236U CN 205861236 U CN205861236 U CN 205861236U CN 201620760431 U CN201620760431 U CN 201620760431U CN 205861236 U CN205861236 U CN 205861236U
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Abstract
This utility model relates to a kind of novel platinum thermal resistance sensor temperature collection circuit.Including the first circuit being sequentially connected with and second circuit, described first circuit is constant voltage partial pressure type three-wire system temperature measurement circuit, is used for eliminating transmission line resistance；Described second circuit is reverse low-pass filter amplifier, for the electric power environmental series mode interference of intensifier circuit.This utility model circuit uses three-wire system thermometric, difference subtraction amplifier processes line resistance signal, the reverse low pass filter of then signal entrance carries out anti-interference process, last AD gathers signal, this novel circuit completely on hardware circuit by line resistance, various series mode interference have processed, and make the temperature signal collected more accurate, more reliable.
Description
Technical field
This utility model relates to a kind of novel platinum thermal resistance sensor temperature collection circuit.
Background technology
Temperature controller is used widely in fields such as commercial production, power equipment, communication apparatus.Aborning, temperature
Degree is extremely important technological parameter, and in power equipment runs, temperature is also very important on the impact of power equipment, institute
It is indispensable with the control accurate, stable to temperature controller.
Field of electrical equipment is very important to the detection of power equipment running temperature, daily life, production, factory's fortune
Row etc. all be unable to do without electricity, so to ensure the transmission of the stable safety of electricity, it is necessary that the safe operation of power equipment.At present
The Electric control field commonly used platinum resistance thermometer sensor, of thermometric, platinum resistance has that temperature-measuring range is big, accuracy is high, stable performance, repetition
Property the feature such as good, be a kind of more satisfactory detector unit.But platinum resistance is due to the shadow such as lead resistance, various environmental disturbances
Ringing, temperature measurement accuracy is affected, and even results in control by mistake and causes power equipment to trip, and on producing, living, impact is the biggest.
Based on the electricity importance to our daily life, the monitoring to power equipment is also most important.To power equipment
The problem that running environment thermometric mainly has three aspects: one, the resistance of platinum resistance thermometer sensor, own is little, and electric power monitoring district and measurement zone away from
From the most farther out, line resistance is bigger on the impact of temperature；Two, sensor experiences failure, circuit comes off to be needed to detect and report
Alert；Three, power equipment running environment is complicated, various harmonic waves, and series mode interference is big on temperature signal impact.Traditional temperature measuring equipment exists
Eliminate line resistance aspect and mainly use three-wire system balanced bridge method and three-wire system constant voltage dividing potential drop method.
(1) three-wire system balanced bridge method
For Pt100 platinum resistance thermometer sensor, international temperature scale BS-90 is given its resistance and varies with temperature shown in relation such as formula (1).
In formula, Rt be thermal resistance in the resistance that temperature is when t DEG C, R0 is that thermal resistance is at the resistance that temperature is when 0 DEG C, R0=
100 Ω, A=3.968 47 × 10-3 DEG C-1, B=-5.847x10-7 DEG C-2, C=-4.22x10-12 DEG C-3 is and sensor self
Relevant coefficient.
From formula (1), the sensitivity of Pt100 thermal resistance be about 0.38 Ω/DEG C, for reduce connect wire line electricity
The resistance impact on measurement result, general conventional three-wire system bridge method measures.Its circuit theory of VR=1 V is as shown in Figure 1.Rt
For temperature detecting resistance, r is for connecting conductor resistance, and R1, R2, R3 are fixing brachium pontis, and R1=R2=1 000 Ω, R3=100 Ω, VR are base
Quasi-reference voltage, G is measuring instruments.In the circuit, 3 wires connect sensor brachium pontis, resistance brachium pontis and outfan respectively.
Use this method can measure testing resistance Rt easily.But, when actually used, temperature sensor and temperature measurement circuit
Between often have a certain distance, the resistivity connecting wire is about 0.1～0.5 Ω/m, connects the survey caused by conductor resistance r
Amount error can not be ignored.
Electric bridge as shown in Figure 1, when not considering line resistance r, electric bridge is output as: V ' c=VRRt/ (R1+Rt)-
VRR3/ (R2+R3), it is considered to during line resistance, electric bridge output Vc=VR (Rt+r)/(R1+Rt+r)-VR (R3+r)/(R2+R3+r),
Assume electric bridge bridge balance, i.e. R2Rx=R1R3 when Rt=Rx, and meet arm resistance R1=R2=R3=Rx=R, when Rt occurs △ R
During change, i.e. Rt=R+ △ R, can calculate the error that now electric bridge causes because of the existence of line resistance r is:
Can be seen that conductor resistance r affects the measurement result of Rt, and cannot be completely eliminated by zeroing circuit.
(2) three-wire system constant voltage dividing potential drop method
Constant voltage partial pressure type three-wire system method measuring resistance can get rid of conductor resistance, and its equivalent schematic diagram is as shown in Figure 2.Wherein Rt
For thermal resistance.R is wire equivalent resistance.Reference voltage on the basis of VR, VAD is the reference voltage of A/D converter, and β is that voltage is put
Big multiple.
Basic relational expression can be obtained by Ohm's law:
Can be calculated by relation above formula:
From formula (3) it can be seen that in the case of known Rv and VR, Rt to be asked only need to measure V2 and V1, and electric with wire
It doesn't matter for resistance r.And certainty of measurement is solely dependent upon precision and the V1 of RV, the certainty of measurement of V2.Bridge method cannot eliminate
Conductor resistance is completely eliminated in constant voltage partial pressure type three-wire system method.
Be above two kinds of at present conventional thermometric Acquisition Circuit, scheme one eliminate on line resistance complete not, thermometric away from
Away from from, when line resistance is big, eradicating efficacy is bad；Scheme two is eliminating on line resistance well by complete, at a distance for line resistance process
Testing temperature is no problem, but AD gathers letter process and must gather two signals (V1, V2), needs to design two-way AD in design and adopts
Collection or employing switch switching gather signal.But thermal resistance signal is the least signal to be easily subject to circuit in transmitting procedure and does
The impact disturbed, above-mentioned two scheme does not the most process at anti-interference aspect, so comparing shortcoming in actual applications,
Comprehensive above scheme, devises a novel thermometric Acquisition Circuit.
Summary of the invention
The purpose of this utility model is to provide a kind of novel platinum thermal resistance sensor temperature collection circuit, and this circuit makes to adopt
The temperature signal that collection arrives is more accurate, more reliable.
For achieving the above object, the technical solution of the utility model is: a kind of novel platinum thermal resistance sensor temperature acquisition
Circuit, including the first circuit being sequentially connected with and second circuit, described first circuit is constant voltage partial pressure type three-wire system temperature measurement circuit,
For eliminating transmission line resistance；Described second circuit is reverse low-pass filter amplifier, for the electric power environmental string of intensifier circuit
Mould disturbs.
In this utility model one embodiment, described first circuit include thermal resistance sensor, the first to the 3rd line resistance,
First to fourth resistance, the first amplifier, one end of described thermal resistance sensor is connected to the ground through First Line resistance, and thermal resistance passes
One end of sensor is also connected to the positive input of the first amplifier through the second line resistance, the first resistance, thermal resistance sensor another
One end of one end the 3rd line resistance and the second resistance, the 3rd resistance connects, the other end of the second resistance and input power anode
Connecting, the other end of the 3rd resistance is connected to the anti-phase input of the first amplifier, and the other end of the 3rd resistance is also through the 4th resistance
It is connected to the outfan of the first amplifier, and as the outfan of the first circuit, the positive power source terminal of described first amplifier, negative electricity
Source is connected with input power anode, input power negative terminal respectively.
In this utility model one embodiment, described 3rd resistance, the 4th resistance resistance identical, the resistance of the first resistance
It is the 3rd resistance, the half of the 3rd resistance.
In this utility model one embodiment, described second circuit includes the 5th to the 7th resistance, electric capacity, the second amplification
Device, A/D module, the outfan of described first circuit is through described 5th resistance and the anti-phase input of the second amplifier, the 6th resistance
One end, one end of electric capacity connect, and the outfan of the other end of the 6th resistance, the other end of electric capacity and the first amplifier connects, and
Being connected to A/D module, the positive input of described second amplifier is connected to the ground through the 7th resistance, the positive electricity of described second amplifier
Source, negative power end are connected with input power anode, input power negative terminal respectively.
In this utility model one embodiment, the resistance of described 5th resistance and the 6th resistance is identical.
In this utility model one embodiment, described thermal resistance sensor is platinum thermal resistance sensor.
In this utility model one embodiment, the extended line of described first to the 3rd i.e. platinum thermal resistance sensor of line resistance produces
Raw line resistance.
Compared to prior art, this utility model has the advantages that this utility model uses three-wire system thermometric, poor
Dividing subtraction amplifier to process line resistance signal, the reverse low pass filter of then signal entrance carries out anti-interference process, and last AD gathers
Signal, this novel circuit completely on hardware circuit by line resistance, various series mode interference have processed, the temperature letter making to collect
Number more accurate, more reliable.
Accompanying drawing explanation
Fig. 1 is existing three-wire system bridge balance measurement schematic diagram.
Fig. 2 is existing constant voltage partial pressure type three-wire system method measuring principle figure.
Fig. 3 is novel platinum thermal resistance sensor temperature collection circuit principle schematic of the present utility model.
Detailed description of the invention
Below in conjunction with the accompanying drawings, the technical solution of the utility model is specifically described.
As it is shown on figure 3, one of the present utility model novel platinum thermal resistance sensor temperature collection circuit, including being sequentially connected with
The first circuit and second circuit, described first circuit is constant voltage partial pressure type three-wire system temperature measurement circuit, is used for eliminating transmission line electricity
Resistance；Described second circuit is reverse low-pass filter amplifier, for the electric power environmental series mode interference of intensifier circuit.Described first electricity
Road includes thermal resistance sensor, the first to the 3rd line resistance, first to fourth resistance, the first amplifier, and described thermal resistance senses
One end of device is connected to the ground through First Line resistance, and one end of thermal resistance sensor is also connected to through the second line resistance, the first resistance
The positive input of the first amplifier, the other end of thermal resistance sensor through the 3rd line resistance and the second resistance, the one of the 3rd resistance
End connects, and the other end of the second resistance is connected with input power anode, and the other end of the 3rd resistance is connected to the first amplifier
Anti-phase input, the other end of the 3rd resistance is also connected to the outfan of the first amplifier through the 4th resistance, and as the first circuit
Outfan, the positive power source terminal of described first amplifier, negative power end are respectively with input power anode, input power negative terminal even
Connect.Described second circuit includes the 5th to the 7th resistance, electric capacity, the second amplifier, A/D module, the outfan of described first circuit
Connect through described 5th resistance and the anti-phase input of the second amplifier, one end of the 6th resistance, one end of electric capacity, the 6th resistance
The outfan of the other end, the other end of electric capacity and the first amplifier connects, and is connected to A/D module, and described second amplifier is just
Input mutually and be connected to the ground through the 7th resistance, the positive power source terminal of described second amplifier, negative power end respectively with input power anode,
Input power negative terminal connects.
Described 3rd resistance, the 4th resistance resistance identical, the resistance of the first resistance is the 3rd resistance, the 3rd resistance
Half.The resistance of described 5th resistance and the 6th resistance is identical.
Described thermal resistance sensor is platinum thermal resistance sensor.Described first to the 3rd i.e. platinum thermal resistance sensor of line resistance
Extended line produce line resistance.
Below for this utility model circuit implement principle.
As it is shown on figure 3, novel platinum thermal resistance sensor temperature collection circuit of the present utility model, this circuit is divided into two parts
Processing two problems described above, a long-distance transmissions line resistance problem respectively, another electric power environmental series mode interference is asked
Topic.Circuit concrete analysis is as follows:
Circuit 1 part uses the elimination line resistance circuit that constant voltage partial pressure type three-wire system method is designed after transformation, above
Having made a concrete analysis of constant voltage partial pressure type three-wire system method and eliminated the effect of line resistance, r is line resistance in circuit, and Rt is thermal resistance
Sensor, eliminates line resistance and is calculated as:
VRt=I*Rt=V1-Vr-Vr (1)
V1=VRt+2Vr=I* (Rt+2r) (2)
V2=Vr=I*r (3)
V3=2*V2-V1=-VRt (4)
Show that the value of V3 is finally for the negative value of VRt from calculating (4).
Circuit 2 part is reverse low-pass filter amplifier, and its result of calculation is as follows:
V4=-β*V3=-(R3/R2)*V3 (5)
V4=(R3/R2)* VRt (6)
Circuit 2 filter factor Fp=1/ (2 π * R2*C1) (7)
After signal is amplified by circuit 2 part, AD, end temperature signal value is inputted owing to the signal of thermal resistance own is smaller
For (R3/R2) * VRt.
After above two parts electrical combination, signal value line resistance is basically eliminated, and circuit 2 enhances the anti-dry of Acquisition Circuit
Disturb ability so that the temperature signal collected is more accurate, stable.
In actual applications, platinum thermal resistance sensor extended line should accomplish that length is the same, the most such guarantee of material
Line resistance on every line is basically identical, and the elimination of line resistance could be more perfect.
It is above preferred embodiment of the present utility model, all changes made according to technical solutions of the utility model, is produced
Function without departing from the scope of technical solutions of the utility model time, belong to protection domain of the present utility model.
Claims (7)
1. a novel platinum thermal resistance sensor temperature collection circuit, it is characterised in that: include the first circuit of being sequentially connected with and
Second circuit, described first circuit is constant voltage partial pressure type three-wire system temperature measurement circuit, is used for eliminating transmission line resistance；Described second electricity
Road is reverse low-pass filter amplifier, for the electric power environmental series mode interference of intensifier circuit.
Novel platinum thermal resistance sensor temperature collection circuit the most according to claim 1, it is characterised in that: described first electricity
Road includes thermal resistance sensor, the first to the 3rd line resistance, first to fourth resistance, the first amplifier, and described thermal resistance senses
One end of device is connected to the ground through First Line resistance, and one end of thermal resistance sensor is also connected to through the second line resistance, the first resistance
The positive input of the first amplifier, the other end of thermal resistance sensor through the 3rd line resistance and the second resistance, the one of the 3rd resistance
End connects, and the other end of the second resistance is connected with input power anode, and the other end of the 3rd resistance is connected to the first amplifier
Anti-phase input, the other end of the 3rd resistance is also connected to the outfan of the first amplifier through the 4th resistance, and as the first circuit
Outfan, the positive power source terminal of described first amplifier, negative power end are respectively with input power anode, input power negative terminal even
Connect.
Novel platinum thermal resistance sensor temperature collection circuit the most according to claim 2, it is characterised in that: described 3rd electricity
Resistance, the 4th resistance resistance identical, the resistance of the first resistance is the 3rd resistance, the half of the 3rd resistance.
Novel platinum thermal resistance sensor temperature collection circuit the most according to claim 2, it is characterised in that: described second electricity
Road includes the 5th to the 7th resistance, electric capacity, the second amplifier, A/D module, and the outfan of described first circuit is through described 5th electricity
Hinder and be connected with the anti-phase input of the second amplifier, one end of the 6th resistance, one end of electric capacity, the other end of the 6th resistance, electric capacity
The other end and the outfan of the first amplifier connect, and be connected to A/D module, the positive input of described second amplifier is through the
Seven resistance are connected to the ground, and the positive power source terminal of described second amplifier, negative power end are born with input power anode, input power respectively
End connects.
Novel platinum thermal resistance sensor temperature collection circuit the most according to claim 4, it is characterised in that: described 5th electricity
Hinder identical with the resistance of the 6th resistance.
6. according to the novel platinum thermal resistance sensor temperature collection circuit described in claim 2 or 4, it is characterised in that: described heat
Electric resistance sensor is platinum thermal resistance sensor.
Novel platinum thermal resistance sensor temperature collection circuit the most according to claim 6, it is characterised in that: described first to
The line resistance that the extended line of the 3rd i.e. platinum thermal resistance sensor of line resistance produces.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201620760431.2U CN205861236U (en) | 2016-07-20 | 2016-07-20 | Novel platinum thermal resistance sensor temperature collection circuit |
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| CN201620760431.2U CN205861236U (en) | 2016-07-20 | 2016-07-20 | Novel platinum thermal resistance sensor temperature collection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112526066A (en) * | 2020-11-20 | 2021-03-19 | 深圳市森世泰科技有限公司 | Gas concentration measuring device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112526066A (en) * | 2020-11-20 | 2021-03-19 | 深圳市森世泰科技有限公司 | Gas concentration measuring device and method |
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