CN2510837Y - Temperature measurement circuit model set of sea-floor heat probe - Google Patents
Temperature measurement circuit model set of sea-floor heat probe Download PDFInfo
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- CN2510837Y CN2510837Y CN 01270013 CN01270013U CN2510837Y CN 2510837 Y CN2510837 Y CN 2510837Y CN 01270013 CN01270013 CN 01270013 CN 01270013 U CN01270013 U CN 01270013U CN 2510837 Y CN2510837 Y CN 2510837Y
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- temperature
- thermal probe
- circuit module
- multiplexer
- measuring circuit
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Abstract
Disclosed is a temperature measurement circuit module group for submarine thermal probe, which has a constant current element, an A/D transition element, two multiplexers, a plurality of reference resistances and thermistors etc, matching trilinear grounding loop, composing an innovative multiplex trilinear thermistor measuring circuit, the multiplexer and the grounding loop provide each channel with same electric and temperature characteristics, achieving effect of decreasing interference of external noise and increasing analytic degree.
Description
Technical field
The utility model relates to the temperature measurement technology field, especially carry out the temperature measuring circuit module of a kind of seabed thermal probe of ground thermal measurement at marine bottom sediment, circuit arrangement by multiplex's three-wire type thermistor etc., to reach effects such as reducing wiring number, the outside noise interference of attenuating, further obtain the thermograph of high-res.
Background technology
The seabed main purpose of ground hot-probing is to find out the underground heat flow valuve, further know geologic background and the ground body structure of measuring ground by the size of underground heat flow valuve, wherein the underground heat flow valuve is with underground temperature gradient obtain with the sediment heat-conduction coefficient (underground heat flow valuve=underground temperature gradient value * sediment heat-conduction coefficient) on duty, so the design of seabed thermal probe is mainly promptly obtaining this thermograde value and sediment heat-conduction coefficient.And the seabed thermal probe of commonly seeing, be to be provided with seven thermal sensors (thermalsensor) in instrument, and each thermal sensor spacing 40-100 centimetre, can rely on the power effect like this for support and insert the sea bed surface deposit, and then record the temperature of the various different depths of sediment, try to achieve the underground temperature gradient value with this.And this seabed thermal probe can be by discharge mode, make electric current pass through resistance wire and heat release, just can learn the sedimental heat-conduction coefficient that probe inserts with thermal sensor record variation of temperature again, can try to achieve the underground heat flow valuve according to aforesaid way like this, the unit of its hot-fluid is: heatflowunit (hfu)=10-6calcm-2s-1=4.18 * 10-2Wm-2.
The temperature measuring circuit module framework of traditional seabed thermal probe, (as shown in Figures 1 and 2) thus thermistor (thermistor) constitute the thermometric equivalent electrical circuit of direct current, wherein RL1, RL2 are the stray resistance (parasitic) that is serially connected with the thermistor two ends, comprise connection resistance, connector contact resistance and line resistance etc.; At the voltage of A/D (analog to digital converter) input end is Vad=1s * (RL1+RL2+RT), extremely make (RL1+RL2) Vad ≈ 1s * RT when being lower than RT when the wiring of this thermistor RT like this near A/D, the resolution of the big more then circuit of the resistance value of thermistor is high more under this framework, promptly lowers the influence of circuit stray resistance with the high resistance thermistor.But this kind circuit framework can't be reached effective raising for accuracy of measurement and resolution, mainly be because of:
1, hot noise (the Thermal Noise of thermistor, Et=(4KTR Δ f) 1/2, K is Boltzmann ' s constant in the formula, T is Temperature in Kelvin, R is Resistance, Δ f is Noise bandwidth in hertz) be proportional to its resistance value, so its resistance value of the thermistor of high precision designs usually in smaller value.
2, after thermistor wiring length is higher than certain-length, its line resistance value just can't be ignored.
3, when using multiplex (MUX) (multiplex) method to connect a plurality of thermistor simultaneously, in the circuit except this connection resistance, more internal resistance values of multiplexer, and this resistance value has hundred ohm of sizes approximately.
4, also temperature influence of these stray resistances itself can't further promote the resolution of temperature.
So (please refer to shown in Figure 3) general commercially available its resolution of seabed thermal probe only is 0.7 ℃, is under 0.02 ℃ of situation at the temperature axis scale, measures temperature damping's curve of marine bottom sediment and resolve not good.
Edge this, for overcoming the measuring error that connection resistance causes and promoting its resolution, relevant dealer proposes the metering circuit design that a kind of three-wire type connects, (as shown in Figure 4) this three-wire type circuit connecting be in above-mentioned basic metering circuit, add second constant current source (constant currentsource) 12 together ground circuit in order to the payment error that RL1, RL2 produced.Suppose that this RL1 also is complementary with big or small identical (wiring and joint use identical material equal length usually) and the current source of RL2, then because of error voltage that RL1 produced is identical with error voltage on the RL2, behind the differential voltage of input a/d converter (differential) input end because of the i.e. payment voluntarily of error voltage that RL1, RL2 produced.And produce the voltage drop that is twice on RL1, the RL2 on the connection resistance limit RL3 of common ground circuit, but this voltage is common mode (common mode) voltage, does not exert an influence for the A/D converter of used difference input.Reference voltage is taken out by the current source voltage drop that is produced on the Rref of flowing through, and can eliminate the error that is produced because of each component temperature coefficient.
Though above-mentioned three-wire type connection has good characteristic, but when number of active lanes increases, the wiring volume just becomes one and bears greatly, system with the temperature inductor of one seven passage, as long as the tradition connection is 14 wiring, above-mentioned three-wire type connection then needs 21 wiring, know when the temperature decline curve that utilizes after the resistance wire heat release is found the solution sedimental heat-conduction coefficient, The sooner the better for radiating efficiency, therefore in the thermal probe pipe of seabed except will installing seven thermistors, still need and install two resistive heaters additional, therefore real difficult 21 connections that in the finite space, adopt, and back panel wiring too much also hinders the transmission of heat again, the time of delay measurements, really non-rational design.
Summary of the invention
Fundamental purpose of the present utility model, it is the temperature measuring circuit module that is to provide a kind of seabed thermal probe, make seabed thermal probe circuit framework have a constant flow element, an A/D conversion element, two multiplexers, a plurality of reference resistance and a plurality of thermistors etc., constitute the metering circuit of multiplex's three-wire type thermistor whereby, make several thermistors can shared same current source and A/D converter with multiplexer, identical electric and temperature characterisitic is all arranged to reach each passage.
An of the present utility model purpose, it is the temperature measuring circuit module that is to provide a kind of seabed thermal probe, be further to utilize a constant current source, an A/D converter, two multiplexers, a plurality of reference resistance and a plurality of thermistors to mate the common ground circuit of improveing basic three-wire connections and forming, make several thermistors constitute the measurement current return by shared ground circuit altogether to be total to ground circuit, provide the A/D converter input end can adopt the differential type input, disturb to lower outside noise, reach the effect of promoting seabed thermal probe resolution.
The purpose of this utility model is achieved in that
Adopt a probe tube to be provided with several thermistors and constitute the thermometric equivalent electrical circuit of three-wire type direct current in its intermediate reach, in circuit, be provided with the constant flow element that comprises two constant current sources, and in circuit, be provided with an A/D conversion element, wherein constant flow element is connected with a multiplexer MUX1 and makes electric current and distribute to use, and the A/D conversion element is connected do input selection use with another multiplexer MUX2, and make several thermistors be connected with multiplexer MUX1 output terminal, and multiplexer MUX2 output terminal is connected with the wiring of seven thermistors, and make one of the common use of several thermistors be total to the ground circuit connection as measuring current return, so promptly construct the temperature measuring circuit that becomes multiplex's three-wire type thermistor, the geothermal heat flow that can be provided as marine bottom sediment is measured.
Description of drawings
Figure 1 shows that the equivalent circuit diagram that the traditional thermal resistance temperature is measured;
Figure 2 shows that the equivalent circuit diagram that general thermistor temp is measured;
Figure 3 shows that the analysis diagram that general thermistor temp is measured;
Figure 4 shows that the three-wire type thermistor temp metering circuit figure that commonly sees;
Figure 5 shows that the thermometric synoptic diagram of the utility model marine bottom sediment;
Figure 6 shows that the temperature measuring circuit figure of many merits of the utility model three-wire type;
Figure 7 shows that the utility model thermistor invests the synoptic diagram of probe tube;
Figure 8 shows that the bulk temperature record diagram that the utility model seabed each thermistor of thermal probe is reacted in measuring process;
Figure 9 shows that the utility model utilizes thermograph in 12 minutes just can inquire into the due temperature synoptic diagram of sediment behind the deduction frictional heat;
Figure 10 shows that the utility model utilizes the temperature decline curve after the heat release just can try to achieve sedimental heat-conduction coefficient figure;
Figure 11 shows that the thermometric analysis diagram of the utility model sediment.
Embodiment
Extremely shown in Figure 7 as Fig. 5, " the temperature measuring circuit module of seabed thermal probe " of the present utility model, mainly be to comprise a constant flow element 1, an A/D conversion element 2, two multiplexer MUXI, MUX2, number reference resistance and several thermistors 3 etc., and the formed ground circuit 4 altogether of the basic three-wire connection of coupling improvement constitutes, wherein:
Constant flow element 1, its inside has two 100uA constant current sources that coupling is good, do to make in the temperature two constant current source electric currents output difference to be lower than 0.25% (actual selecting when using is lower than 0.1%) at 0-25 ℃ whereby, the temperature contrast that two constant current sources are caused keeps far below the difference between two thermistors (0.05 ℃), promptly the constant current source temperature contrast is about 0.0006 ℃ @5 ℃ in twos, and it is calculated as follows:
Thermister?YSI?46047?6KΩ?@25℃
4-5 ℃ of resistance variations is 16.02K Ω-15.24K Ω
The about 180 Ω @7.5V VDD of multi-function device AD 407 passage internal resistances, 25 ℃
0.000609 ℃ of current source temperature error=(180+10) * 0.0025/16020-15240 ≈
A/D conversion element 2, it is converted into galvanic rectifier for a kind of alternating current, comprise preposition signal processing capacity, and use SIGMA-DELTA A/D switch technology, and have high-res (24bits), low noise (150nV), low consumption electric current (350uA), differential type signal input (the interference resistant function is strong) and differential type reference voltage input functions such as (being easy to the resistance measurement of usage ratio formula);
Multiplexer MUX1, MUX2 (multiplexer), have another name called and be data selector switch (dataselector), and meet two multiplexer MUX1, MUX2, can be in digital display circuit, more than one digital signal need be transported to single receiving end, can determine that by the coding on the selection wire numerical data of one of them passage is read on the input end;
Reference resistance, because the resistance measurement of usage ratio formula is converted to temperature with it again, therefore reference resistance has decisive influence power for instrument accuracy grade and resolution, the superprecision reference resistance that the utility model adopted must possess extremely low temperature coefficient (@25 ℃ of 0.3PPM/ ℃), high accuracy (± 0.01 ℃ @25 ℃) and low-heat noise (Thermal EMF) characteristic;
Thermistor 3, it constitutes the temperature sense resistive element of the utility model seabed thermal probe, and possess low temperature drift (Thermometric Drift-＜0.01 ℃ per 100 months@25 ℃), relative error little (＜± 0.05 ℃) are arranged, reaction velocity fast (2.5SEC Bath) and glass material sealing characteristic functions such as (not perishable);
Whereby, the temperature measuring circuit of the seabed thermal probe 10 of the utility model indication, system adopts the needle tubing that diameter is eight least bit, be provided with seven thermistors 3 (thermistor) in its intermediate reach (spacing can be adjusted) and constitute the thermometric equivalent electrical circuit of direct current between the 40-100 centimetre, in the basic circuit of this three-wire connection, be provided with the constant flow element 1 that comprises two 100uA constant current sources, and in circuit, be provided with an A/D conversion element 2, wherein this constant flow element 1 is connected with a multiplexer MUX1 and makes electric current and distribute to use, and A/D conversion element 2 is connected do input selection use with another multiplexer MUX2, and make seven thermistors 3 be connected with multiplexer MUX1 output terminal, and multiplexer MUX2 output terminal is connected with the wiring of seven thermistors 3, and make 3 one of the common use of seven thermistors be total to ground circuit 4 connections as measuring current return, so promptly construct the temperature measuring circuit that becomes multiplex's three-wire type thermistor, can be provided as the ground thermal measurement of marine bottom sediment.
Because the utility model is in the advantage with three-wire type connection, be provided with multiplexer MUX1, MUX2 and improve the three-wire type connection and have altogether ground circuit 4, therefore this multiplexer MUX1, MUX2 can make several thermistors 3 can a shared constant flow element 1 and A/D conversion element 2, therefore each passage has identical circuit and temperature characterisitic, can reduce each interchannel difference.And altogether ground circuit 4 constitutes the temperature measuring circuit of multiplex's three-wire type thermistors, A/D conversion element 2 input ends because constant current source 1 electric current is not flowed through, so A/D conversion element 2 input ends can adopt the differential type input, disturb with the outside noise of further attenuating.The design of ground circuit 4 has reduced the wiring number really altogether again, so the utility model is implemented in the tiny thermal probe more than conventional three-wire formula connection is easier.And each interchannel difference of reaching by the utility model reduces and reduces the effect of external disturbance, and the temperature resolution that can promote seabed thermal probe 10 can be better than 0.1m ℃ (the traditional wired method only can reach in 0.7m ℃).
As shown in Figure 5, the utility model thermal probe 10 reality write down the job step of temperature at sea, be that thermal probe 10 is sunk down into apart from the seabed about 30 meters from the deck constant speed on the ship, the measured temperature of this section sinking time is the temperature of seawater, and be the stability that keeps thermal probe 10, make in the insertion sediment that it can be upright, thermal probe 10 must stop about 5 minutes with as each thermistor 3 usefulness of correction each other, and the temperature that measure seawater this moment keeps certain value generally.Vertically pour thermal probe 10 in the marine bottom sediment more whereby, wait for and measured sedimental temperature variation (as shown in Figure 9 0) in about 12 minutes, just can infer sediment subtracted probe friction give birth to temperature after due temperature, can be used to calculate underground temperature gradient (being the thermogram of seven thermistors of whole operation process as shown in Figure 8).And then the thermal pulse of emitting about 10 seconds makes its heat release, temperature is sharply raise after decline gradually, can calculate sedimental heat-conduction coefficient by the temperature decline curve, as shown in figure 10.Because the utility model resolution is 0.1m ℃, so show that through amplifying the record of measuring temperature obtains high effect of resolving as seen from Figure 11, more attains precision more than traditional resolution 0.7m ℃ (aforementioned shown in Figure 3).Obtaining geothermic gradient and sedimental heat-conduction coefficient whereby can above aforementioned manner (underground heat flow valuve=underground temperature gradient value * sediment heat-conduction coefficient), and then obtain the underground heat flow valuve on stratum, seabed, and can know geothermal structure, geologic background and the ground body structure of measuring ground by inference.
Claims (7)
1, the temperature measuring circuit module of a kind of seabed thermal probe includes constant flow element, A/D conversion element, multiplexer, a plurality of reference resistance and a plurality of thermistor, it is characterized in that:
In a probe tube, be provided with these a plurality of thermistors equally spacedly and constitute the thermometric equivalent electrical circuit of three-wire type direct current, this constant flow element comprises two constant current sources, and in this circuit module, be provided with an A/D conversion element, wherein this constant flow element is connected with a multiplexer (MUX1) and makes electric current and distribute to use, and this A/D conversion element is connected do input selection use with another multiplexer (MUX2), and these a plurality of thermistors of order are connected with multiplexer (MUX1) output terminal, and multiplexer (MUX2) output terminal is connected with the wiring of these a plurality of thermistors, and makes one of the common use of these a plurality of thermistors be total to the ground circuit connection as measuring current return.
2, the temperature measuring circuit module of seabed thermal probe according to claim 1 is characterized in that: this constant flow element inside has two 100uA constant current sources of coupling mutually, and its temperature contrast is about 0.0006 ℃ @5 ℃.
3, the temperature measuring circuit module of seabed thermal probe according to claim 1, it is characterized in that: this A/D conversion element, for a kind of alternating current is converted to galvanic rectifier, comprise preposition signal processing capacity, and use SIGMA-DELTA A/D switch technology, its resolution is that 24bits, noise are 150nV, power consumption stream is for 350uA and has the input of differential type signal and the input of differential type reference voltage.
4, the temperature measuring circuit module of seabed thermal probe according to claim 1, it is characterized in that: this multiplexer (MUX1), (MUX2) are a kind of single receiving end of more than one digital signal can being transported in digital display circuit, promptly can determine the element that the numerical data of one of them passage is read on the input end by the coding on the selection wire.
5, the temperature measuring circuit module of seabed thermal probe according to claim 1, it is characterized in that: this reference resistance is accurate reference resistance, its temperature is that @25 ℃ of 0.3PPM/ ℃, accuracy are ± 0.01 ℃ @25 ℃.
6, the temperature measuring circuit module of seabed thermal probe according to claim 1, it is characterized in that: this thermistor is the temperature sense resistive element, its temperature drift (Thermometric Drift)＜0.01 ℃ per100 months ℃, relative error＜± 0.05 ℃, reaction velocity are 2.5SEC Bath, and adopt not perishable glass material sealing.
7, the temperature measuring circuit module of seabed thermal probe according to claim 1 is characterized in that this thermal probe pipe diameter is 8 millimeters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01270013 CN2510837Y (en) | 2001-10-31 | 2001-10-31 | Temperature measurement circuit model set of sea-floor heat probe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01270013 CN2510837Y (en) | 2001-10-31 | 2001-10-31 | Temperature measurement circuit model set of sea-floor heat probe |
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| Publication Number | Publication Date |
|---|---|
| CN2510837Y true CN2510837Y (en) | 2002-09-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01270013 Expired - Lifetime CN2510837Y (en) | 2001-10-31 | 2001-10-31 | Temperature measurement circuit model set of sea-floor heat probe |
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| CN (1) | CN2510837Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102353470A (en) * | 2011-09-30 | 2012-02-15 | 国电南京自动化股份有限公司 | Voltage dynamic tracking thermal resistance measurement method |
| CN104062692A (en) * | 2014-07-08 | 2014-09-24 | 广州海洋地质调查局 | High-precision seabed terrestrial heat flow detection device |
-
2001
- 2001-10-31 CN CN 01270013 patent/CN2510837Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102353470A (en) * | 2011-09-30 | 2012-02-15 | 国电南京自动化股份有限公司 | Voltage dynamic tracking thermal resistance measurement method |
| CN104062692A (en) * | 2014-07-08 | 2014-09-24 | 广州海洋地质调查局 | High-precision seabed terrestrial heat flow detection device |
| CN104062692B (en) * | 2014-07-08 | 2017-02-15 | 广州海洋地质调查局 | High-precision seabed terrestrial heat flow detection device |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CX01 | Expiry of patent term |
Expiration termination date: 20111031 Granted publication date: 20020911 |