CN210426805U - High-reliability high-precision temperature measuring circuit for spaceflight - Google Patents
High-reliability high-precision temperature measuring circuit for spaceflight Download PDFInfo
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- CN210426805U CN210426805U CN201920621680.7U CN201920621680U CN210426805U CN 210426805 U CN210426805 U CN 210426805U CN 201920621680 U CN201920621680 U CN 201920621680U CN 210426805 U CN210426805 U CN 210426805U
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Abstract
The utility model belongs to a temperature measurement circuit field for the space flight especially relates to a high-reliable high accuracy temperature measurement circuit for the space flight, including platinum resistance sensor bleeder circuit, fortune circuit, AD acquisition circuit, main control unit. The method has the advantages of mild reaction conditions, low requirement on equipment materials and low manufacturing cost; automatic control is set, so that the labor intensity of personnel operation is reduced, and the error rate is reduced; automatic control is set, and the product quality is stable.
Description
Technical Field
The utility model belongs to a temperature measurement circuit field for the space flight especially relates to a high-reliability high accuracy temperature measurement circuit for the space flight.
Background
In recent years, with rapid development of science and technology, temperature measurement is an increasingly important place in the fields of industry, agriculture, scientific research, aerospace and the like. In particular, the requirement on the temperature control precision in the field of aerospace is extremely high, and accurate temperature measurement is an important measurement parameter in aerospace.
With the increasing importance of the country on the aspect of aerospace, the requirement of accurate temperature measurement is also shown, and the variation of the environmental temperature is sometimes very small, and sometimes reaches +/-1 ℃, +/-0.5 ℃, +/-0.1 ℃ and the like, and even higher. Because the temperature change in the aerospace field is complex and changeable, the design of a temperature measurement circuit with high reliability and high precision is very necessary. The accurate temperature measurement and control can effectively improve the stability and reliability of spaceflight,
for the measurement of temperature, the existing methods are many, and the existence of a signal of a sensor during measurement can be divided into non-electrical measurement and electrical measurement; the contact mode of the sensor to be measured and the object to be measured is classified into a contact type and a non-contact type.
The expansion type temperature measurement is carried out by utilizing the principle of expansion with heat and contraction with cold of a substance, namely the relation between the volume of an object and the change of temperature, and the temperature measurement precision of the method is low.
The contact type photoelectric measurement is that a thermal radiation signal caused by temperature is led out by contacting a measured object, temperature measurement is carried out through a photoelectric conversion device, and a sensor is required to be contacted with the measured object in the temperature measurement process. The measuring method has the advantages that the measuring method is not easily interfered by external electromagnetic interference, and has the defect that the measured object is interfered to cause measuring errors.
The electric quantity type measuring and temperature measuring method measures the potential, resistance and other electric properties of the material according to the relationship between the temperature and the potential. Including thermal resistance measurements, thermocouple measurements, and the like.
Non-contact temperature measurement methods such as radiation method temperature measurement, spectroscopic temperature measurement, laser method temperature measurement, and the like. Compared with a contact temperature measurement method, the non-contact temperature measurement method is not in contact with a measurement object, does not interfere the temperature of the measured object, but is influenced by a measurement medium and a measurement environment, and signals are unstable.
Therefore, a highly reliable and highly accurate temperature measuring circuit for aerospace use is urgently needed to be provided, and the reliability can be improved while high-accuracy measurement is carried out.
SUMMERY OF THE UTILITY MODEL
The utility model provides a high-reliability high-precision temperature measuring circuit for spaceflight for solve the problem that exists among the present background art.
A high-reliability high-precision temperature measurement circuit for spaceflight comprises a platinum resistance sensor voltage division circuit, an operational amplifier circuit, an AD acquisition circuit and a main controller; platinum resistance sensor bleeder circuit through the electricity connect transmit to with the fortune is amplified circuit, the signal process fortune is amplified the back and is transmitted to through the electricity connection the AD acquisition circuit in turn to analog signal serial data and through the electricity connection transmission extremely in the AD acquisition circuit in the main control unit, and by the main control unit passes through data connector output.
Further, the platinum resistance sensor voltage division circuit comprises a platinum resistance sensing circuit and a voltage division circuit; the platinum resistor sensing circuit is connected with the platinum resistor and outputs variable voltage Z _ TEMP _ YC _1 which changes along with temperature; the voltage division circuit always outputs a fixed voltage Z _ TEMP _ YC __ REF _1, and the platinum resistance sensor voltage division circuit simultaneously outputs a variable voltage signal and a fixed voltage signal.
Furthermore, the temperature characteristic of the voltage dividing resistor of the voltage dividing circuit is +/-10 multiplied by 10-6/K。
Furthermore, the temperature characteristic of the resistance of the operational amplifier circuit is +/-10 multiplied by 10-6And the operational amplifier adopts OP400 AY.
Furthermore, the AD acquisition circuit adopts AD7890 as an A/D converter.
Further, the master controller employs XQ6SLX 75T.
Further, the AD acquisition circuit is connected with more than one operational amplifier circuit.
Further, the operational amplifier circuit is connected with more than one platinum resistance sensor voltage division circuit.
Furthermore, the high-reliability high-precision temperature measurement circuit for spaceflight further comprises a power module and a power interface, wherein the power interface supplies power to the operational amplifier circuit, the AD acquisition circuit and the main controller respectively through the power module.
The utility model has the advantages that:
1. the temperature measurement range is wide, and the temperature measurement device can adapt to a high-temperature or low-temperature working state;
2. the high-precision resistor is used, so that the influence of temperature is overcome, and the operational amplifier with low noise and low temperature drift is used, so that the influence of noise on the measurement precision is overcome;
3. along with the change of the external temperature, the error generated by the influence of the external temperature on the whole temperature measuring circuit is small, the reliability and the measuring precision are improved, and the precision of the whole measuring circuit can reach 0.3K.
Drawings
FIG. 1 is a schematic view of the connection structure of the present invention;
FIG. 2 is a logic block diagram of the present invention;
fig. 3 is a voltage dividing circuit diagram of the platinum resistance sensor of the present invention;
fig. 4 is a circuit diagram of the operational amplifier of the present invention;
fig. 5 is the AD acquisition circuit diagram of the present invention.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Example 1
As shown in fig. 1-5, a high-reliability high-precision temperature measurement circuit for aerospace comprises a platinum resistance sensor voltage division circuit, an operational amplifier circuit, an AD acquisition circuit, and a main controller; platinum resistance sensor bleeder circuit through the electricity connect transmit to with the fortune is amplified circuit, the signal process fortune is amplified the back and is transmitted to through the electricity connection the AD acquisition circuit in turn to analog signal serial data and through the electricity connection transmission extremely in the AD acquisition circuit in the main control unit, and by the main control unit passes through data connector output.
In this embodiment, the platinum resistance sensor voltage dividing circuit includes a platinum resistance sensing circuit and a voltage dividing circuit; the platinum resistor sensing circuit is connected with the platinum resistor and outputs variable voltage Z _ TEMP _ YC _1 which changes along with temperature; the voltage division circuit always outputs a fixed voltage Z _ TEMP _ YC __ REF _1, and the platinum resistance sensor voltage division circuit simultaneously outputs a variable voltage signal and a fixed voltage signal.
In this embodiment, the AD acquisition circuit is connected to more than one of the operational amplifier circuits.
In this embodiment, the operational amplifier circuit is connected to more than one platinum resistance sensor voltage divider circuit.
In this embodiment, aerospace is with high-reliable high accuracy temperature measurement circuit still includes power module, power source passes through power module is respectively for the operational amplifier circuit AD acquisition circuit the main control unit power supply.
Selecting the type of the temperature measuring sensor: for precision and reliability that realize improving the temperature measurement circuit, the utility model discloses will use PT1000 thermal resistance to measure as temperature sensor.
The advantage of using platinum resistor PT1000 to measure temperature is:
1. the physical property and the chemical property of the platinum are very stable, and oxidation-reduction reaction is not easy to occur.
2. The specific resistance of platinum is large.
3. The temperature coefficient of platinum is relatively large, and the average temperature coefficient is about 3.925 x 10 between 0 and 100 DEG C-3℃-1。
4. The relation between the resistance of the platinum and the temperature is smooth, and calculation is convenient.
The resistance of the platinum resistor PT1000 is related to the temperature as follows:
when the temperature is-200 DEG C<t<At 0 ℃, Rt＝R0[1+At+Bt2+C(t-100)t3]
When the temperature is 0 DEG C<t<At 850 ℃, Rt＝R0[1+At+Bt2]
Wherein:
Rtis the resistance value at t ℃, R0Is the resistance value at 0 ℃. And t is the measured temperature.
A is constant equal to 118.477473278402, B is constant equal to-0.000246002468134874, and C is constant equal to 0.110012529165921.
The use method of the high-reliability high-precision temperature measuring circuit comprises the following steps:
the method comprises the following steps: the whole test circuit is powered on through a power module, as shown in a platinum resistor voltage division circuit in fig. 3, a connection position of a platinum resistor sensor is at a position J1, and the rest of the platinum resistor voltage division circuit divides a 1.8V voltage by a voltage division resistor, the principle is that the resistance value of the platinum resistor is influenced by temperature and can change, when the resistance value of the platinum resistor changes, in the circuit, the voltage divided by the platinum resistor can change along with the change of the output voltage to be Z _ TEMP _ YC _1, the voltage divided by the other group of resistors always outputs a fixed voltage value to be Z _ TEMP _ YC __ REF _1, and at the moment, the platinum resistor voltage division circuit can output two groups of voltage values, one group of which is the fixed voltage value, and the other group of voltage value changes. In order to improve the measurement accuracy, the allowable deviation of the resistance value of the used voltage dividing resistor needs to be very small, a high-precision sheet type film fixed resistor is selected for the purpose, the allowable deviation of the resistance value is +/-0.05%, and in order to reduce the influence of the external temperature on the voltage dividing resistor in the voltage dividing circuit, the temperature characteristic of the selected resistor is +/-10 multiplied by 10 < -6 >/K.
Step two: the differential operational amplifier circuit, as shown in fig. 4, inputs two groups of voltage values output by the platinum resistor voltage division circuit into the same differential amplifier circuit, and obtains a stable voltage signal through operational amplification. In order to stabilize the amplification factor of the operational amplifier circuit and avoid the influence of the external temperature, a high-precision chip type film fixed resistor with the resistance value allowable deviation of +/-0.05% and the resistance temperature characteristic of +/-10 multiplied by 10 < -6 >/K is also selected. In order to improve the precision, the selection of the operational amplifier is also very important, and the operational amplifier selects OP400AY, and has the advantages of extremely low input offset voltage, low noise of 11 nV/Hz at 1kHz, high open-loop gain of 5000V/mV, low offset voltage drift of 1.2 PV/DEG C at the maximum of-55 ℃ to +125 ℃ and the like.
Step three: referring to fig. 5, the electrical signal amplified by the operational amplifier circuit of the previous stage reaches the AD acquisition circuit, and the AD circuit is completed by an integrated a/D converter AD 7890. The AD7890 is a low power, high precision, high speed 12-bit a/D converter. The chip is internally provided with 8 single-end analog input channels, allows control of channel selection and can convert analog signals into serial data to be output, and the AD7890 provides a serial port through which a high-speed serial interface can be connected to a DSP or an FPGA.
Step four: main control unit uses Xilinx's FPGA, and the model is XQ6SLX75T, controls AD conversion chip and gathers the serial data of AD output.
Step five: in order to improve the measurement accuracy, the temperature measurement circuit needs to be calibrated, a high-precision resistor box is used for replacing a platinum resistor PT1000 to calibrate the whole measurement circuit, the high-precision resistor box is connected into a voltage division circuit, the resistance value of the high-precision resistor box is changed to simulate the resistance value change of the platinum resistor caused by temperature change, so that the nominal value of the corresponding temperature measurement point is calibrated, and the generated voltage signal passes through an operational amplifier circuit, an AD acquisition circuit and the corresponding measured value calculated by an upper computer by changing the resistance value of the high-precision resistor box. The measurement data are shown in Table 1:
TABLE 1 measurement data Table
As can be seen from the table data, under the condition that the calibration error is accurate enough, the whole circuit meets the requirement of high precision.
In order to detect that the temperature measurement error of the whole circuit is very small under the condition of different temperatures, the whole measuring circuit is placed in a thermostat, and 3 temperature points are randomly selected for testing.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.
Claims (8)
1. A high-reliability high-precision temperature measurement circuit for spaceflight is characterized by comprising a platinum resistance sensor voltage division circuit, an operational amplifier circuit, an AD acquisition circuit and a main controller; the platinum resistance sensor voltage division circuit comprises a platinum resistance sensing circuit and a voltage division circuit; the platinum resistor sensing circuit is connected with the platinum resistor and outputs variable voltage Z _ TEMP _ YC _1 which changes along with temperature; the voltage dividing circuit always outputs a fixed voltage Z _ TEMP _ YC __ REF _1, and the platinum resistance sensor voltage dividing circuit simultaneously outputs a variable voltage signal and a fixed voltage signal; platinum resistance sensor bleeder circuit through the electricity connect transmit to with the fortune is amplified circuit, the signal process fortune is amplified the back and is transmitted to through the electricity connection the AD acquisition circuit in turn to analog signal serial data and through the electricity connection transmission extremely in the AD acquisition circuit in the main control unit, and by the main control unit passes through data connector output.
2. The aerospace high-reliability high-precision temperature measuring circuit according to claim 1, wherein the voltage dividing circuit has a voltage dividing resistance temperature characteristic of ± 10 x 10-6/K。
3. The aerospace high-reliability high-precision temperature measuring circuit according to claim 1, wherein the temperature characteristic of the resistance of the operational amplifier circuit is ± 10 x 10-6And the operational amplifier adopts OP400 AY.
4. The aerospace high-reliability high-precision temperature measuring circuit according to claim 1, wherein the AD acquisition circuit adopts AD7890 as an A/D converter.
5. The aerospace high-reliability high-precision temperature measuring circuit of claim 1, wherein the main controller adopts XQ6SLX 75T.
6. The aerospace high-reliability high-precision temperature measuring circuit according to claim 1, wherein the AD acquisition circuit is connected with more than one operational amplifier circuit.
7. The aerospace high-reliability high-precision temperature measuring circuit according to claim 1, wherein the operational amplifier circuit is connected with more than one platinum resistance sensor voltage dividing circuit.
8. The aerospace high-reliability high-precision temperature measuring circuit according to any one of claims 1-7, further comprising a power module and a power interface, wherein the power interface supplies power to the operational amplifier circuit, the AD acquisition circuit and the main controller through the power module.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920621680.7U CN210426805U (en) | 2019-04-30 | 2019-04-30 | High-reliability high-precision temperature measuring circuit for spaceflight |
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| CN201920621680.7U CN210426805U (en) | 2019-04-30 | 2019-04-30 | High-reliability high-precision temperature measuring circuit for spaceflight |
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| CN210426805U true CN210426805U (en) | 2020-04-28 |
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| CN201920621680.7U Active CN210426805U (en) | 2019-04-30 | 2019-04-30 | High-reliability high-precision temperature measuring circuit for spaceflight |
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