CN112798129A - Temperature measuring device - Google Patents
Temperature measuring device Download PDFInfo
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- CN112798129A CN112798129A CN202011608091.9A CN202011608091A CN112798129A CN 112798129 A CN112798129 A CN 112798129A CN 202011608091 A CN202011608091 A CN 202011608091A CN 112798129 A CN112798129 A CN 112798129A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/22—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
Abstract
The invention discloses a temperature measuring device, which adopts a resistive temperature measuring element of a temperature measuring element to be matched with a temperature measuring circuit to measure temperature. The temperature measuring element adopts a four-wire connection method; setting a temperature measuring circuit according to a proportional method measuring principle; the periphery of a lead wire led out by the temperature measuring element and a lead wire extension line is coated with a conductor reference layer, and the conductor reference layer of the lead wire and the lead wire extension line is electrically connected with a reference layer or a grounding end of the temperature measuring circuit board; the two ends of the lead and the lead extension line respectively have similar or equal temperature; switching the current direction of the current flowing through the temperature measuring element at fixed time intervals, and adding and calculating voltage measured values collected before and after the primary current direction; therefore, interference signals introduced by factors such as wire resistance, impedance matching, signal crosstalk and thermoelectric effect in the temperature measuring device are inhibited or eliminated, and the temperature measuring precision is improved.
Description
Technical Field
The invention belongs to the technical field of temperature measurement, and relates to a temperature measuring device.
Background
In advanced manufacturing fields, which often require the use of high precision thermometers, such as in lithographic apparatus in the semiconductor manufacturing field, many sites require temperature control in the range of 20-24 ℃ and temperature fluctuations over time of no more than 0.05 ℃; in order to meet the requirement of temperature control precision, a temperature measuring device serving as one of the temperature feedback control assemblies needs to have excellent measurement precision, and the measurement precision of the temperature measuring device is usually required to be better than 0.01 ℃ or even 0.001 ℃. The temperature measuring device realizes high-precision temperature measurement, requires a temperature measuring element to have good precision, and also needs to be matched with a power and signal processing circuit to have good precision.
In the prior art, resistive electrical elements such as Resistance Temperature Detectors (RTDs) or thermistors are often used as Temperature-sensing elements. The RTD is a resistor made of a metal material, the resistance of which varies with temperature; the RTD is a high-precision temperature measurement element, is suitable for the temperature range of minus 200 ℃ to plus 850 ℃, has excellent long-term stability, has a relatively simple signal processing method, and is widely applied to the field of precision temperature measurement. The thermistor is a resistor made of metal oxide, the resistance of the thermistor can change along with the temperature change, the resistance value of the common type thermistor decreases along with the temperature rise, the thermistor can normally work in the range of-40 ℃ to +150 ℃, the precision is best at 0 ℃ to 100 ℃, the cost of the thermistor is low, but the nonlinearity degree of the relationship between the resistance value and the temperature is high. The basic principle of temperature measurement using RTDs or thermistors is the measurement of resistance. In a high-precision temperature measuring device, in addition to the precision of the RTD itself as a temperature measuring element, the temperature measuring precision is also influenced by factors such as resistance, impedance matching, signal crosstalk, thermoelectric effect, and the like of a lead of a temperature measuring circuit; particularly, on the occasion that the temperature measurement precision is better than 0.01 ℃, the precision of the temperature measurement circuit has obvious influence on the temperature measurement precision.
Disclosure of Invention
The invention aims to provide a temperature measuring device for realizing high-precision temperature measurement by using a resistive temperature detector.
A temperature measuring device comprises a temperature measuring resistor temperature measuring element, a reference resistor, a current source, a voltage measurer and a connector; the temperature measuring element is a resistive electric element, and the resistance value of the temperature measuring element changes along with the change of temperature; the temperature measuring resistance temperature measuring element adopts a four-wire connection method, a lead is led out from one end of the temperature measuring resistance temperature measuring element and is electrically connected with one pole of the current source, and a lead is led out from the other end of the temperature measuring resistance temperature measuring element and is electrically connected with the other pole of the current source or a grounding end; the two ends of the temperature measuring resistance and temperature measuring element are respectively led out of a lead wire and are electrically connected with the first input end of the voltage measurer; the reference resistor is connected with the temperature measuring element of the temperature measuring resistor in series, and leads are led in from two ends of the reference resistor and are electrically connected with the second input end of the voltage measurer; the current source, the voltage measurer, the reference resistor and the grounding end are positioned on the temperature measuring circuit board; four leads led out from the temperature measuring resistance and temperature measuring element are electrically connected with the extension lead through a lead connector on the connector, and the extension lead is connected with the current source, the voltage measurer and the grounding end through a wiring terminal on the temperature measuring circuit board;
the conducting wire and the extension conducting wire led out from the temperature measuring resistance temperature measuring element are respectively coated with a conductor reference layer which is electrically insulated with the conducting wire and the extension conducting wire, and the conductor reference layer coated outside the conducting wire and the extension conducting wire is electrically connected through a reference layer connecting head on the connector; the temperature measuring circuit board comprises a circuit board reference layer, the circuit board reference layer is a conductor interlayer in the circuit board, and the circuit board reference interlayer covers the current source, the reference resistor, the voltage measurer and the projection of the connected wires on the circuit board, but is not electrically connected with the current source, the reference resistor, the voltage measurer and the connected wires; the conductor reference layer is electrically connected with the circuit board reference layer, and the conductor reference layer is electrically connected with a grounding end on the temperature measuring circuit board.
The circuit board reference layer is electrically connected with the grounding end of the temperature measuring circuit board.
And all the lead wire connector lugs on the connector are positioned on the same connector, so that all the lead wire connector lugs are thermally coupled.
The wire lugs and the reference layer lugs are continuously coated with alumina or thermally conductive silicone grease.
And all the wiring terminals electrically connected with the temperature measuring element and the extended lead reference layer on the temperature measuring circuit board are continuously coated with alumina or heat-conducting silicone grease.
The lead wire led out from the temperature measuring element, the extension lead wire and the lead wire on the temperature measuring circuit board are made of the same conductive materials.
Two selection switches are arranged on the temperature measuring circuit board, and the temperature measuring element is connected with the reference resistor in series; the two ends of the temperature measuring element and the reference resistor which are connected in series are respectively electrically connected with the selection end of the first selection switch, and the fixed end of the first selection switch is electrically connected with the current source; two ends of the temperature measuring element and the reference resistor which are connected in series are respectively electrically connected with a selection end of a second selection switch, and a fixed end of the second selection switch is connected with a grounding end; and when the first selection switch is selectively connected with one end of the temperature measuring element connected with the reference resistor in series, the second selection switch is selectively connected with the other end of the temperature measuring element connected with the reference resistor in series.
The first selection switch and the second selection switch are switched at fixed time intervals.
The fixed time interval is in the range of 2ms to 500 ms.
A temperature measuring device comprises a temperature measuring resistor temperature measuring element, a reference resistor, a current source, a voltage measurer and a connector; the temperature measuring element is a resistive electric element, and the resistance value of the temperature measuring element changes along with the change of temperature; the temperature measuring resistance temperature measuring element adopts a four-wire connection method, a lead is led out from one end of the temperature measuring resistance temperature measuring element and is electrically connected with one pole of the current source, and a lead is led out from the other end of the temperature measuring resistance temperature measuring element and is electrically connected with the other pole of the current source or a grounding end; the two ends of the temperature measuring resistance and temperature measuring element are respectively led out of a lead wire and are electrically connected with the first input end of the voltage measurer; the reference resistor is connected with the temperature measuring element of the temperature measuring resistor in series, and leads are led in from two ends of the reference resistor and are electrically connected with the second input end of the voltage measurer; the current source, the voltage measurer, the reference resistor and the grounding end are positioned on the temperature measuring circuit board; four leads led out from the temperature measuring resistance and temperature measuring element are electrically connected with the extension lead through a lead connector on the connector, and the extension lead is connected with the current source, the voltage measurer and the grounding end through a wiring terminal on the temperature measuring circuit board; the conducting wire and the extension conducting wire led out from the temperature measuring element are respectively coated with a conductor reference layer which is electrically insulated with the conducting wire and the extension conducting wire, the conductor reference layer coated outside the conducting wire and the extension conducting wire is electrically connected through a reference layer connecting head on the connector, and the conductor reference layer is electrically connected with a grounding end on the temperature measuring circuit board.
The invention adopts RTD or thermistor type temperature measurement element, and cooperates with temperature measurement circuit to measure temperature. The temperature measuring element adopts a four-wire connection method, so that the influence of the resistance of the wire on the temperature measuring precision is eliminated; the influence of factors such as current source output current fluctuation, circuit zero drift and the like on temperature measurement precision is eliminated by using a proportional method measurement principle; the conductor reference layer is coated on the periphery of the lead and the lead extension line led out by the temperature measuring element, and the conductor reference layer of the lead and the lead extension line is electrically connected with the reference layer or the grounding end of the temperature measuring circuit board, so that noise signals introduced by impedance matching, environmental electromagnetic interference and crosstalk factors among leads in the lead are inhibited, and the temperature measuring precision is improved; the two ends of the lead and the extension line of the lead are respectively provided with similar or equal temperature, so that the temperature difference electromotive force interference signals caused by unequal temperatures at the two ends of the lead are inhibited; the current flowing through the temperature measuring element is switched in the current direction at fixed time intervals, the voltage measured values collected before and after the primary current direction are added and calculated, the temperature difference electromotive force interference signals introduced by the temperature gradient in the lead are eliminated, and the temperature measuring precision is improved.
Drawings
FIG. 1 is a schematic circuit diagram of a first embodiment of the present invention;
FIG. 2 is a schematic circuit diagram according to a second embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of a third embodiment of the present invention;
FIG. 4 is a schematic circuit diagram of a fourth embodiment of the present invention;
fig. 5 is a schematic diagram of the principle of eliminating the thermoelectromotive force according to the fourth embodiment of the invention.
Detailed Description
Example one
A temperature measuring device according to the present invention, as shown in fig. 1, includes a temperature measuring element Rs; the temperature measuring element Rs has resistance characteristics and is a resistive electric element, and the temperature is measured according to the rule that the resistance value of the temperature measuring element Rs changes along with the temperature change; the Temperature sensing element Rs may be a Resistance Temperature Detector (RTD), such as a Pt100 type platinum resistor or a PT1000 type platinum resistor; the temperature sensing element Rs may also be a thermistor, such as a model 5611T thermistor available from Fluke, calibrated to an accuracy of 0.0001 ℃. The temperature measuring element Rs is thermally coupled with the object to be measured, the resistance of the temperature measuring element Rs is detected, and the temperature of the temperature measuring element Rs and the object to be measured can be calculated. The temperature measuring element Rs has wiring methods such as a two-wire system, a three-wire system, a four-wire system and the like, and the four-wire system wiring method is used in the invention to eliminate the influence of lead resistance on temperature measuring precision; specifically, two lead terminals 1a and 1b of the temperature measuring element Rs are respectively connected with two poles of a current source Is through power lines 2a and 2 b; the lead terminals 1a and 1b of the temperature measuring element Rs are also connected to a voltage measuring device, which is an analog-to-digital conversion circuit (ADC) or an integrated circuit thereof in this embodiment, through measuring lines 3a and 3b, respectively; the current source Is provides stable current for the temperature measuring element Rs, the resistance value of the temperature measuring element Rs Is calculated by detecting the voltage at the two ends of the temperature measuring element Rs, and then the corresponding temperature value Is calculated. More specifically, in the present embodiment, the resistance value of the temperature measuring element Rs is measured and calculated by a proportional method; a reference resistor Rref Is connected in series between the temperature measuring element Rs and the current source Is, and leads are led out from two ends of the reference resistor Rref and connected into the ADC to detect voltages at two ends of the reference resistor Rref; the reference resistor Rref is a high-precision resistor with a resistance value determined, and the resistance value of the reference resistor Rref can be selected to be equal to that of the temperature measuring element Rs so as to fully utilize the voltage acquisition range of the ADC; placing the reference resistor Rref in a temperature stable environment; the ADC respectively collects voltages at two ends of the temperature measuring element Rs and the reference resistor Rref, and the actual resistance value of the temperature measuring element Rs can be calculated according to the fact that the voltages at the two ends of the temperature measuring element Rs and the reference resistor Rref are in direct proportion to the resistance values of the temperature measuring element Rs and the reference resistor Rref. The actual resistance value of the temperature measuring element Rs is measured by adopting a proportional method, so that the resistance measurement error caused by the fluctuation of the output current of the constant current source can be eliminated, and the measurement error caused by the zero drift and the temperature drift of the circuit can be eliminated.
In many temperature measurement occasions, the position of setting up of temperature measurement element Rs is far away from signal acquisition devices such as ADC, and the wire length between temperature measurement element Rs and the ADC is longer, and the electrical characteristics of wire will produce the influence to the temperature measurement precision: the impedance of the wire and the impedance of the upstream and downstream conductors do not match, causing the signal to oscillate in the wire; crosstalk noise is introduced between two wires at close positions due to mutual inductance and mutual capacitance; the instability of the impedance between the wire and the environment causes noise to be introduced into the transmission signal; temperature unevenness on the wire causes a thermoelectromotive force and the like. In order to improve the temperature measurement accuracy, in this embodiment, the temperature measurement element Rs adopts a four-wire wiring method, two power lines 2a and 2b and two measurement lines 3a and 3b are led out from two ends of the temperature measurement element Rs, and are respectively connected with the extension lead 5 through a lead connector 41a on the connector 4, are connected with the wiring terminal 6 on the temperature measurement circuit board 7 after being extended by the extension lead 5, and are respectively connected with two ends of the current source Is or the input end of the ADC. In order to suppress noise introduced by lead impedance factors, insulating layers are coated outside the power lines 2a and 2b and the measuring lines 3a and 3b, and a conductor layer is further coated outside the insulating layers, wherein the conductor layer can be in a structural form of a metal woven net and can play a role in shielding environmental electromagnetic signal interference; the conductor layers that surround the power lines 2a, 2b and the measuring lines 3a, 3b are electrically connected together to form an equipotential point, which is labeled as a lead reference layer 81 in fig. 1. Similarly, the outer portion of the extended wires 5 is covered with an insulating layer, and a conductor layer is further covered on the outer portion of the insulating layer to play a role of shielding signal interference, so that the conductor layers outside the four extended wires 5 are electrically connected together to form an equipotential point, which is marked as an extended wire reference layer 82 in fig. 1; electrically connecting the lead reference layer 81 and the extended lead reference layer 82 via the reference layer connector 41b of the connector 4; the temperature measuring circuit board 7 comprises a conductor interlayer called a circuit board reference layer 71, wherein the circuit board reference layer 71 covers the current source Is, the reference resistor Rref, the ADC and the projection of the lead wires connected with the current source Is, the reference resistor Rref and the ADC on the circuit board, but Is not electrically connected with the current source Is, the reference resistor Rref, the ADC and the lead wires connected with the current source Is, the reference resistor Rref and the ADC; the noise signals in the wires on the temperature measuring circuit board 7 are connected in an electromagnetic induction mode; electrically connecting the extended lead reference layer 82 with the circuit board reference layer 71 through the reference layer wiring terminal 61; thus, the lead reference layer 81, the extended lead reference layer 82, and the circuit board reference layer 71 form an equipotential reference layer; the lead of the temperature measuring element Rs, the extension lead, the lead on the temperature measuring circuit board 7 and the equipotential reference layer have relatively stable and relatively small impedance, noise signals generated by factors such as environmental interference and crosstalk between lines in the lead tend to be spread to the equipotential reference layer and are consumed, the noise signals in the temperature measuring circuit are restrained, and the temperature measuring precision is improved.
In the present embodiment, it can be considered that the temperature of the temperature measuring element Rs and the lead terminals 1a and 1b thereof is equal and equal to the temperature of the object to be measured; the power lines 2a, 2b and the measuring lines 3a, 3b are positioned in the same connector 4 as the lead connector 41a connected with the extension lead 5, and are positioned in the same connector 4 as the reference layer connector 41b, so that the connectors are well thermally coupled, and the temperatures of the lead connector 41a and the reference layer connector 41b are equal; the current source Is, the ADC, the reference resistor and the Rref are arranged on a temperature measuring circuit board 7 and are placed in an environment with stable temperature, and particularly, the connecting terminals 6 electrically connected with the temperature measuring element Rs on the temperature measuring circuit board 7 are in good thermal coupling. Therefore, the temperatures at the two ends of the power lines 2a and 2b are respectively equal, and the current directions are opposite, so that the thermoelectromotive force caused by the temperature difference at the two ends of the wire can be eliminated, interference signals are reduced, and the temperature measuring precision is improved; similarly, the directions of the thermoelectromotive forces in the measuring lines 2a and 2b are opposite and offset with each other; the thermoelectric electromotive forces on the extension leads of the power line and the measuring line are also opposite in direction and mutually offset. Moreover, the same material is used for the power line 2, the measurement line 3, the extension lead 5, and the conductor on the temperature measurement circuit board 7, so that the thermoelectromotive force generated by the seebeck thermoelectric effect can be eliminated. Therefore, the temperature measuring device of the embodiment reduces the temperature difference electromotive force caused by the temperature difference of the end points in the lead, and improves the temperature measuring precision. The good thermal coupling method for each connector or each terminal may be to use a temperature control container with a temperature regulator to accommodate the connector 4 or the temperature measurement circuit board 7, may be to use the connector 4 packaged by a metal structure, or may be to use good thermal conductors such as alumina or thermal conductive silicone grease to continuously coat the wire connector 41a and the reference layer connector 41b or each terminal 6.
Example two
As shown in FIG. 2, the power lines 1a and 1b of the temperature measuring element Rs are connected to one terminal of the current source Is and the ground GND, respectively, and the lead reference layer 81 and the extension lead reference layer 82 are electrically connected to the ground GND via the reference layer connection terminal 61. The lead reference layer 81, the extended lead reference layer 82 and the ground terminal GND form an equipotential reference layer, and the ground terminal GND has more stable potential and impedance characteristics, which is beneficial to the suppression and elimination of noise signals in the temperature measurement circuit. When the lead connected with the input end of the ADC on the temperature measurement circuit board 7 is short, the electromagnetic interference is less, and a conductor interlayer is not arranged in the circuit board.
The other implementation modes are the same as the first embodiment.
EXAMPLE III
As shown in fig. 3, a circuit board reference layer 71 Is disposed on the temperature measuring circuit board 7, and the circuit board reference layer 71 covers the current source Is, the reference resistor Rref, the ADC and the projection of the lead wires connected thereto on the circuit board, but Is not electrically connected to the current source Is, the reference resistor Rref, the ADC and the lead wires connected thereto; the noise signals in the wires on the temperature measuring circuit board 7 are connected in an electromagnetic induction mode; electrically connecting the extended lead reference layer 82 with the circuit board reference layer 71 through the reference layer wiring terminal 61; thus, the lead reference layer 81, the extended lead reference layer 82, and the circuit board reference layer 71 form an equipotential reference layer; the equipotential reference layer is electrically connected with a ground end GND. The rest of the implementation modes are the same as the second embodiment.
Compared with the second embodiment, the second embodiment adds the circuit board reference layer electrically connected to the ground GND, so as to better suppress the noise signal in the wire of the temperature measurement circuit board 7.
Example four
If the distance between the temperature measuring element Rs and the temperature measuring circuit board 7 is long, a long power line 2, a long measuring line 3 or a long extension wire 5 needs to be used, or the temperature of the environment where the power line 2, the long measuring line 3 or the long extension wire 5 is located is unstable, which may cause a large temperature gradient to be generated in the long power line 2, the long measuring line 3 or the long extension wire 5. The temperature gradient on the lead can generate thermoelectromotive force in the lead due to the thermoelectric effect of Thomson, and the thermoelectromotive force has influence on the temperature measurement precision.
As shown in fig. 4, the temperature measuring circuit board 7 of the temperature measuring device of the present embodiment is provided with two selection switches 9a and 9 b; the temperature measuring element Rs is connected with the reference resistor Rref in series; two ends of the temperature measuring element Rs and the reference resistor Rref which are connected in series are respectively and electrically connected with a selection end of the selection switch 9a, and a fixed end of the selection switch 9a Is connected with the current source Is; similarly, two ends of the temperature measuring element Rs and the reference resistor Rref which are connected in series are respectively electrically connected with a selection end of the selection switch 9b, and a fixed end of the selection switch 9b is connected with a ground end GND; one end of a temperature measuring element Rs can be selected to be communicated with a current source Is through a selection switch 9a, and one end of a reference resistor Rref Is communicated with a ground end GND through a selection switch 9b, so that current flows along a first direction; alternatively, one end of the reference resistor Rref may be selectively connected to the current source Is through the selection switch 9a, while one end of the temperature measuring element Rs may be connected to the ground GND through the selection switch 9b, so that the current flows in a second direction opposite to the first direction. As shown in fig. 5(a) and 5(b) (for simplicity of illustration, the reference resistor Rref part of the circuit is not shown), the selector switches 9a and 9b are switched at regular time intervals to switch the current direction between the first direction and the second direction, and the thermoelectromotive forces Uth1, Uth2, Uth3 and Uth4 generated on the four extension wires 5 due to the temperature gradient will be reversed; the voltage measurement results of two ends of the temperature measuring element Rs measured before and after the current direction is switched along the first direction and the second direction are added, so that the influence of the thermoelectromotive forces Uth1, Uth2, Uth3 and Uth4 on the extension lead 5 in the measurement results can be eliminated; similarly, the influence of the thermoelectric powers Uth1, Uth2, Uth3, and Uth4 on the power line 2 and the measurement line 3 in the measurement result can be eliminated; therefore, the interference of the thermoelectric effect on the temperature measurement signal is reduced, and the temperature measurement precision is improved.
The time interval of the switching selection switches 9a and 9b is properly selected as a small time interval, so that the temperature of the lead and the temperature gradient before and after the current direction is switched are as close as possible, and the effectiveness of eliminating the thermoelectromotive force is improved; however, it is not suitable to select a too small time interval, otherwise, the impact electrical signal generated when the switch is switched is not timely suppressed and eliminated, and the transmission of the temperature measurement signal is interfered. Preferably, the switching time interval of the selection switches 9a and 9b is in the range of 2ms0.5ms-500 ms.
The rest of the embodiments are the same as any one of the first to third embodiments.
The foregoing summary and structure are provided to explain the principles, general features, and advantages of the product and to enable others skilled in the art to understand the invention. The foregoing examples and description have been presented to illustrate the principles of the invention and are intended to provide various changes and modifications within the spirit and scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A temperature measuring device is characterized in that: the temperature measuring device comprises a temperature measuring element, a reference resistor, a current source, a voltage measurer and a connector; the temperature measuring element is a resistive electric element, and the resistance value of the temperature measuring element changes along with the change of temperature; the temperature measuring element adopts a four-wire connection method, a lead is led out from one end of the temperature measuring element and is electrically connected with one pole of the current source, and a lead is led out from the other end of the temperature measuring element and is electrically connected with the other pole of the current source or a grounding end; the two ends of the temperature measuring element are respectively led out of a lead wire and are electrically connected with a first input end of the voltage measurer; the reference resistor is connected with the temperature measuring element in series, and leads are led in from two ends of the reference resistor and are electrically connected with the second input end of the voltage measurer; the current source, the voltage measurer, the reference resistor and the grounding end are positioned on the temperature measuring circuit board; the four leads led out from the temperature measuring element are electrically connected with the extension lead through a lead connector on the connector, and the extension lead is connected with the current source, the voltage measurer and the grounding end through a wiring terminal on the temperature measuring circuit board;
the conducting wire and the extension conducting wire which are led out from the temperature measuring element are respectively coated with a conductor reference layer which is electrically insulated with the conducting wire and the extension conducting wire, and the conductor reference layer coated outside the conducting wire and the extension conducting wire is electrically connected through a reference layer connecting head on the connector; the temperature measuring circuit board comprises a circuit board reference layer, the circuit board reference layer is a conductor interlayer in the circuit board, and the circuit board reference layer covers the current source, the reference resistor, the voltage measurer and the projection of the connected wires on the circuit board, but is not electrically connected with the current source, the reference resistor, the voltage measurer and the connected wires; and the conductor reference layer is electrically connected with the circuit board reference layer.
2. A temperature measuring device according to claim 1, wherein: the circuit board reference layer is electrically connected with the grounding end of the temperature measuring circuit board.
3. A temperature measuring device according to claim 1, wherein: and all the lead wire connector lugs on the connector are positioned on the same connector, so that all the lead wire connector lugs are thermally coupled.
4. A temperature measuring device according to claim 1, wherein: the wire lugs and the reference layer lugs are continuously coated with alumina or thermally conductive silicone grease.
5. A temperature measuring device according to claim 1, wherein: and all the wiring terminals electrically connected with the temperature measuring element and the extended lead reference layer on the temperature measuring circuit board are continuously coated with alumina or heat-conducting silicone grease.
6. A temperature measuring device according to claim 1, wherein: the lead wire led out from the temperature measuring element, the extension lead wire and the lead wire on the temperature measuring circuit board are made of the same conductive materials.
7. A temperature measuring device according to claim 1, wherein: two selection switches are arranged on the temperature measuring circuit board, and the temperature measuring element is connected with the reference resistor in series; the two ends of the temperature measuring element and the reference resistor which are connected in series are respectively electrically connected with the selection end of the first selection switch, and the fixed end of the first selection switch is electrically connected with the current source; two ends of the temperature measuring element and the reference resistor which are connected in series are respectively electrically connected with a selection end of a second selection switch, and a fixed end of the second selection switch is connected with a grounding end; and when the first selection switch is selectively connected with one end of the temperature measuring element connected with the reference resistor in series, the second selection switch is selectively connected with the other end of the temperature measuring element connected with the reference resistor in series.
8. A temperature measuring device according to claim 7, wherein: the first selection switch and the second selection switch are switched at fixed time intervals.
9. A temperature measuring device according to claim 8, wherein: the fixed time interval is in the range of 0.5ms to 500 ms.
10. A temperature measuring device is characterized in that: the temperature measuring device comprises a temperature measuring element, a reference resistor, a current source, a voltage measurer and a connector; the temperature measuring element is a resistive electric element, and the resistance value of the temperature measuring element changes along with the change of temperature; the temperature measuring element adopts a four-wire connection method, a lead is led out from one end of the temperature measuring element and is electrically connected with one pole of a current source, and a lead is led out from the other end of the temperature measuring element and is electrically connected with a grounding end; the two ends of the temperature measuring element are respectively led out of a lead wire and are electrically connected with a first input end of the voltage measurer; the reference resistor is connected with the temperature measuring element in series, and leads are led in from two ends of the reference resistor and are electrically connected with the second input end of the voltage measurer; the current source, the voltage measurer, the reference resistor and the grounding end are positioned on the temperature measuring circuit board; the four leads led out from the temperature measuring element are electrically connected with the extension lead through a lead connector on the connector, and the extension lead is connected with the current source, the voltage measurer and the grounding end through a wiring terminal on the temperature measuring circuit board;
the conducting wire and the extension conducting wire led out from the temperature measuring element are respectively coated with a conductor reference layer which is electrically insulated with the conducting wire and the extension conducting wire, the conductor reference layer coated outside the conducting wire and the extension conducting wire is electrically connected through a reference layer connecting head on the connector, and the conductor reference layer is electrically connected with a grounding end on the temperature measuring circuit board.
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| CN202011608091.9A CN112798129A (en) | 2020-12-30 | 2020-12-30 | Temperature measuring device |
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| CN202011608091.9A CN112798129A (en) | 2020-12-30 | 2020-12-30 | Temperature measuring device |
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