CN211317556U - A ambient temperature monitoring devices for carrier rocket - Google Patents

Abstract

The utility model discloses an ambient temperature monitoring devices for carrier rocket uses integrated chip MAX31856 and MAX31865, and the chip adopts SPI serial bus technique and microprocessor communication, can make the hardware of device simplify, the volume reduces, the reliability improves, makes the upgrading of device and the easy that the extension becomes simultaneously. The device has strong expansibility and diversified selection, can selectively connect thermal resistors of PT100, PT1000 and other models or AD590 and DS18B20, has diversified wiring modes of the thermal resistors, and can select three wiring modes of a two-wire system, a three-wire system and a four-wire system. In addition, the device has excellent electromagnetic compatibility, the anti-interference capability of the sensor is improved, and the device is more reliable than an analog signal.

Description

A ambient temperature monitoring devices for carrier rocket

Technical Field

The utility model belongs to the design field of ambient temperature monitoring especially relates to an ambient temperature monitoring devices for carrier rocket.

Background

The environment experienced from launch vehicle firing to ballistic flight includes heat, vibration, shock, etc. The pneumatic heating of the rocket during flying, the heat generated by the working of the instrument, the temperature reflection of the flame of the engine to the tail part of the rocket, the low-temperature propellant and the like can form a severe thermal environment, and the normal working of the instrument and the performance of materials are influenced. Therefore, the method is particularly important for accurate and high-precision measurement of temperature.

In the traditional carrier rocket environmental parameter monitoring module, a contact thermocouple and a thermal resistor are mostly used for measuring temperature. The thermocouple has the characteristics of simple structure, simplicity in use, easiness in realizing automatic measurement and control, capability of measuring high temperature and relatively mature technology. For a long time, the temperature sensor becomes the main temperature measuring sensor for measuring the temperature of the carrier rocket.

Thermocouples are commonly used for medium to high temperature measurements. The thermocouple is influenced by temperature to generate potential effect, and a differential voltage signal is generated through conversion. The signal is amplified by an amplifier, converted by voltage and current, then output by an independent converter to be 4-20 mA current signal or 0-5 v voltage signal corresponding to the measuring range, and finally output in a long distance and sent to a processor to calculate the actual temperature value. As shown in fig. 1.

However, in the particular environment of a launch vehicle, contact thermocouples have a number of disadvantages.

Firstly, signal conditioning is complex: a separate converter is required to convert the potential signal of the temperature into an analog current or voltage signal to convert the voltage into a usable temperature reading, and the signal conditioning is complicated. Signal conditioning has historically consumed significant design time, and mishandling can introduce errors, resulting in reduced accuracy.

Secondly, the precision is low: in addition to inherent inaccuracies in the thermocouple due to metallic properties, the thermocouple measurement accuracy can only achieve the measurement accuracy of the reference junction temperature, typically within 1 ℃ to 2 ℃.

Thirdly, the noise immunity is poor: noise from stray electric and magnetic fields can cause problems when measuring millivolt-level signal variations.

Fourthly, the cost is high: because the design circuit is complicated, the manpower and material resources used from circuit design, device model selection to PCB manufacture, sample plate debugging and the like are high.

Fifthly, the space utilization rate is low: the large area of the PCB and the large volume of the sensor lead to large space occupied by the single measurement machine, and further lead to low space utilization rate of the effective load of the carrier rocket.

Thermal resistors are generally used for low temperature measurement, and are one of the most common temperature detectors used in medium and low temperature regions. As is known from the principle of measuring the temperature of a thermal resistor, the change in the measured temperature is directly measured by the change in the resistance of the thermal resistor, and therefore, the change in the resistance of various wires such as the lead wire of the thermal resistor affects the temperature measurement. On the other hand, since a minute signal is measured, a differential amplifier circuit, a separate transmitter, or the like is used.

In conclusion, the multifunctional environmental parameter monitoring module of the traditional carrier rocket has the advantages of inheritance, high reliability after being subjected to task inspection for many times. The traditional environmental parameter monitoring module has the disadvantages of complex signal conditioning and low precision; the available space occupied by the arrow body is large, and the space utilization rate of the effective load is low; the power supply voltages of the sensors are inconsistent, the number of conversion circuits is large, the power supply voltage is too high, and the energy consumption is too large; the power supply battery pack is more, the size is large, and the weight is heavy; the sensor is older in model, and poor in precision and instantaneity.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an ambient temperature monitoring devices for carrier rocket can realize the temperature test of high accuracy, low-power consumption, and simple structure, small, light in weight.

In order to solve the above problem, the technical scheme of the utility model is that:

an ambient temperature monitoring device for a launch vehicle, comprising:

a microprocessor for controlling the operation of the microprocessor,

the first converter is connected with the microprocessor through an SPI bus and converts data acquired by the resistance-type temperature sensor into a digital temperature value and transmits the digital temperature value to the microprocessor;

the second converter is connected with the microprocessor through an SPI bus and converts data collected by the thermocouple temperature sensor into a digital temperature value and transmits the digital temperature value to the microprocessor;

the first temperature detector is connected with the microprocessor through a single data bus and transmits the acquired temperature value to the microprocessor; the detection range of the first temperature detector is-55 ℃ to +125 ℃;

the second temperature detector is electrically connected with the microprocessor and transmits the acquired data to the microprocessor; the detection range of the second temperature detector is-55 ℃ to +150 ℃, and high impedance is output.

According to an embodiment of the present invention, the first converter is a MAX31865 chip, a pin SCLK of the MAX31865 chip is connected to a pin CLK of the SPI bus, a pin SDI of the MAX31865 chip is connected to a pin SIMO of the SPI bus, and a pin SDO of the MAX31865 chip is connected to a pin SOMI of the SPI bus;

the resistance type temperature sensor is PT100, and the PT100 can be connected with the MAX31865 chip by adopting a two-wire system or three-wire system or four-wire system connection mode.

According to an embodiment of the present invention, the second converter is a MAX31856 chip, a pin SCK of the MAX31856 chip is connected to a pin CLK of the SPI bus, a pin SDI of the MAX31856 chip is connected to a pin SIMO of the SPI bus, and a pin SDO of the MAX31856 chip is connected to a pin SOMI of the SPI bus;

the MAX31856 chip is connected with the thermocouple temperature sensor in a twisted mode through a shielding cable, temperature lookup tables of thermocouples with different division numbers are integrated in the MAX31856 chip, and the temperature lookup tables conduct nonlinear correction on temperature data collected by the thermocouple temperature sensor.

According to the utility model discloses an embodiment, first thermoscope is DS18B20 digital temperature sensor, and it is a plurality of to connect in parallel on the single strip data bus DS18B20 digital temperature sensor realizes the multiple spot temperature measurement.

According to the utility model discloses an embodiment, the second thermoscope is AD590 temperature sensor, AD590 temperature sensor's positive pole with the microprocessor electricity is connected, AD590 temperature sensor's negative pole ground connection.

The utility model discloses owing to adopt above technical scheme, make it compare with prior art and have following advantage and positive effect:

1) the environmental temperature monitoring device for the carrier rocket in one embodiment of the utility model adopts the thermocouple to detect the temperature aiming at the prior environmental temperature monitoring device, the thermocouple needs to be processed by signal amplification, and then processed by an independent converter which converts a temperature potential signal into an analog quantity current or voltage signal, and then the actual temperature value is calculated by a microprocessor, so that the signal conditioning is complex, a large amount of time is consumed, if the processing is improper, the problem of reduced precision can be caused, the utility model discloses connect a converter between microprocessor and thermocouple, convert the data that the thermocouple gathered into digital temperature value and transmit for microprocessor, need not to handle through a plurality of devices, just can make microprocessor obtain the temperature value that the thermocouple detected, simplified the signal conditioning process greatly, shortened signal conditioning time, improved the temperature detection precision; and the volume of the device is reduced, and the device is more suitable for a carrier rocket.

2) The utility model relates to an ambient temperature monitoring devices for carrier rocket in the embodiment, the problem that the detection precision is low (the precision is 1 ℃) to current temperature-detecting device, the utility model discloses a MAX31865 chip is as signal conditioning device, and the nominal temperature resolution ratio of this MAX31865 chip can reach 0.03125 ℃, under operating condition, and the precision can keep at 0.5 ℃, has improved the temperature detection precision greatly.

3) The utility model discloses an ambient temperature monitoring devices for carrier rocket in the embodiment, when measuring millivolt level signal change to current temperature-detecting device, can't shield the problem of the noise that stray electric field and magnetic field produced, the utility model discloses a MAX31856 chip links to each other with the thermocouple in the mode of stranded wiring, can reduce magnetic field coupling by a wide margin to shield the noise that stray magnetic field produced; in addition, the shielding cable is adopted as the connecting wire, so that the electric field coupling can be reduced, and the noise generated by a stray electric field can be shielded.

4) The environmental temperature monitoring device for the carrier rocket in an embodiment of the present invention, because the AD590 temperature sensor is used to detect the temperature, the output of the device has high impedance, on one hand, the device can keep normal work even if the device uses the well-insulated twisted pair to output for a long distance (25 meters); on the other hand, the influence of supply voltage drift and ripple on temperature detection can be greatly eliminated.

5) The utility model discloses an ambient temperature monitoring devices for carrier rocket in the embodiment adopts the thermal resistance to detect to current temperature-detecting device, and the thermal resistance generally is used for microthermal measurement, the problem of unable measurement high temperature, the utility model discloses a DS18B20 digital temperature sensor, its temperature measurement scope is-55 ℃ - +125 ℃, but measuring 125 ℃'s high temperature has enlarged temperature-detecting device's temperature measurement scope.

Drawings

FIG. 1 is a schematic structural diagram of a conventional device for detecting temperature by using a thermocouple;

fig. 2 is a schematic structural diagram of an ambient temperature monitoring device for a launch vehicle according to an embodiment of the present invention;

fig. 3 is a wiring diagram of a MAX31865 chip according to an embodiment of the present invention;

fig. 4 is a wiring diagram of a MAX31856 chip according to an embodiment of the present invention.

Description of reference numerals:

1: a microprocessor; 2: MAX31865 chip; 3: a PT100 temperature sensor; 4: MAX31856 chip; 5: a thermocouple; 6: DS18B20 digital temperature sensor; 7: AD590 temperature sensor.

Detailed Description

The following provides a further detailed description of the ambient temperature monitoring device for a launch vehicle according to the present invention with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more fully apparent from the following description and appended claims.

The utility model provides an ambient temperature monitoring devices for carrier rocket, as shown in FIG. 2, include: the temperature measuring device comprises a Microprocessor (MCU)1, a first converter (MAX31865 chip 2), a second converter (MAX31856 chip 4), a first temperature detector (DS18B20 digital temperature sensor 6) and a second temperature detector (AD590 temperature sensor 7).

Specifically, the MAX31865 chip 2 is connected to the microprocessor 1 via an SPI bus, and converts data collected by the resistance temperature sensor (PT100 temperature sensor 3) into a digital temperature value and transmits the digital temperature value to the microprocessor 1. As shown in FIG. 3, the SCLK pin of the MAX31865 chip 2 is connected to the CLK pin of the SPI bus, the SDI pin of the MAX31865 chip 2 is connected to the SIMO pin of the SPI bus, and the SDO pin of the MAX31865 chip 2 is connected to the SOMI pin of the SPI bus. The MAX31865 chip 2 is compatible with two-wire, three-wire, and four-wire sensor connection modes, and for example, a PT100 temperature sensor 3 is connected to each of the FORCE +, RTDIN +, and RTDIN-pins of the MAX31865 chip 2.

The utility model discloses a MAX31865 chip 2 that the integrated level is high, the technique is mature has the integrated level height, and the system low power dissipation can simplify the design, reduces design cycle's advantage. The MAX31865 chip 2 supports a platinum resistor of 100 ohms to 1000 ohms and is compatible with sensor connection modes such as a two-wire system, a three-wire system and a four-wire system. The platinum resistor is connected to the MAX31865 chip 2 by a twisted shielded cable, and the voltage value collected by the platinum resistor is converted into a digital value within 21ms by a 15-bit analog/digital converter built in the MAX31865 chip 2. The MAX31865 chip 2 and the microprocessor 1 adopt an SPI communication mode to form a master-slave relationship, and the microprocessor 1 polls each MAX31865 chip 2 in a time-sharing mode through an SPI bus to obtain a temperature value detected by each PT100 temperature sensor 3. The nominal temperature resolution of this MAX31865 chip 2 was 0.03125 ℃ (non-linearly dependent on RTD), and the total accuracy was kept at 0.5 ℃ (equivalent to 0.05% full scale) throughout the operating conditions.

The MAX31856 chip 4 is connected with the microprocessor 1 through an SPI bus, and converts data collected by the thermocouple 5 into digital temperature values and transmits the digital temperature values to the microprocessor 1. As shown in fig. 4, pin SCK of the MAX31856 chip 4 is connected to pin CLK of the SPI bus, pin SDI of the MAX31856 chip 4 is connected to pin SIMO of the SPI bus, and pin SDO of the MAX31856 chip 4 is connected to pin SOMI of the SPI bus. The pins BIAS, T + and T-of the MAX31856 chip 4 are connected with a thermocouple 5, and the MAX31856 chip 4 is internally provided with a 19-bit analog-to-digital converter (ADC) with an internal temperature sensor which can automatically compensate the thermocouple 5 at the cold end. The MAX31856 chip 4 is internally provided with temperature lookup tables supporting thermocouples 5 with different graduation numbers, the temperature lookup tables can perform nonlinear correction on data acquired by the thermocouples 5, and output data is formatted in centigrade without conversion. The temperature resolution of the MAX31856 chip 4 is 0.0078125 ℃, allowing temperature values ranging from +1800 ℃ to-210 ℃ (depending on the type of thermocouple 5) to be read, and the voltage measurement accuracy of the thermocouple 5 can reach 0.15V. The connection line of the thermocouple 5 and the MAX31856 chip 4 adopts a twisting mode, so that the magnetic field coupling can be greatly reduced; in addition, the shielding cable or the wiring and protection in the metal conduit can reduce the electric field coupling and shield the noise generated by the stray electric field or magnetic field.

The MAX31856 chip 4 and the microprocessor 1 adopt SPI communication mode to form a master-slave relationship. Because the traditional method for calculating the temperature is to acquire voltage to an ADC (analog to digital converter), the temperature value is calculated; the ADC of the microprocessor is typically 12 bits, which results in a low sampling accuracy. The utility model discloses a MAX31856 chip 4 can utilize its built-in 19 bit analog-to-digital converter (ADC) to obtain the sampling value of higher accuracy to give microprocessor 1 with the sampling value through the SPI communication, its precision can reach 0.1 ℃.

The DS18B20 digital temperature sensor 6 is connected with the microprocessor 1 through a single data bus and transmits the acquired temperature value to the microprocessor 1; the temperature detection range is-55 ℃ to +125 ℃. The DS18B20 digital temperature sensor 6 has the characteristics of simple circuit design and small volume, when a temperature measurement system is formed, a plurality of DS18B20 digital temperature sensors 6 can be connected in parallel by only one bus, multi-point temperature measurement is realized, and networking is very convenient. The DS18B20 digital temperature sensor 6 has 4 components inside: the temperature sensor, 64-bit ROM, non-volatile temperature alarm triggers TH and TI and a configuration register adopt an online temperature measurement technology, and the measurement precision is +/-0.5 ℃ at minus 10-85 ℃. The temperature measuring cable is one shielded four-core twisted pair cable with one pair comprising ground wire and signal wire and the other pair comprising power wire and ground wire, and the shielding layer is grounded in single point at the power end. The DS18B20 digital temperature sensor 6 transmits in a single bus data mode, greatly improves the anti-interference capacity of the device, and has small volume and high precision (the precision can reach 0.625 ℃ when 12 bits).

The AD590 temperature sensor 7 is electrically connected with the microprocessor 1, and transmits the acquired data to the microprocessor 1 for processing and calculating the measured temperature value. The anode of the AD590 temperature sensor 7 is electrically connected to the microprocessor 1, and the cathode of the AD590 temperature sensor 7 is grounded. The AD590 temperature sensor 7 has a temperature detection range of-55 ℃ to +150 ℃ and outputs high impedance, so that the long-distance output of a well-insulated twisted pair has little influence on the operation of the device, and the device can normally operate at a distance of 25 m. And the high output impedance can well eliminate the influence of power supply voltage drift and ripple. The AD590 operates on the principle that the output current varies with the same amount as the temperature, and the output current increases by 1 μ a for every 1℃ increase based on zero (-273 ℃) of the absolute temperature, so that the output current Iout is 298 μ a (273+25) at room temperature of 25 ℃.

The AD590 temperature sensor 7 works by adopting a single power supply, and the current is output instead of the voltage, so that the anti-interference capability is strong, and the required power is low (1.5mv/+5v/+25 ℃), so that the AD590 temperature sensor 7 is particularly suitable for motion measurement.

The utility model provides an ambient temperature monitoring devices for carrier rocket uses integrated chip MAX31856 and MAX31865, and the chip adopts SPI serial bus technique and microprocessor 1 communication, can make the hardware of device simplify, the volume reduces, the reliability improves, makes the upgrading of device and the easy that the extension becomes simultaneously. The device has strong expansibility and diversified selection, can selectively connect thermal resistors of PT100, PT1000 and other models or AD590 and DS18B20, has diversified wiring modes of the thermal resistors, and can select three wiring modes of a two-wire system, a three-wire system and a four-wire system. In addition, the device has excellent electromagnetic compatibility, the anti-interference capability of the sensor is improved, and the device is more reliable than an analog signal.

The device can be arranged on the first stage of the carrier rocket, can measure a plurality of multipoint temperature data curves on the first stage contact end surface and the second stage contact end surface when the first stage and the second stage of the carrier rocket are thermally separated, and the temperature data curves can reflect the distribution conditions of the temperature on the first stage contact end surface and the second stage contact end surface when the first stage and the second stage of the carrier rocket are thermally separated, thereby having important significance for the optimization and innovation of the structure and the material of the power device of the carrier rocket. The device overcomes the defects of the traditional monitoring device and has the advantages of small volume, light weight, self-contained battery supply, low power consumption, high measurement precision, high downlink speed, strong real-time performance and the like. In the process of acceptance, the normal work of high-speed operation after the carrier rocket takes off can be ensured through the examination of various environments.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, the changes are still within the scope of the present invention if they fall within the scope of the claims and their equivalents.

Claims (5)

1. An ambient temperature monitoring device for a launch vehicle, comprising:

a microprocessor for controlling the operation of the microprocessor,

the first converter is connected with the microprocessor through an SPI bus and converts data acquired by the resistance-type temperature sensor into a digital temperature value and transmits the digital temperature value to the microprocessor;

the second converter is connected with the microprocessor through an SPI bus and converts data collected by the thermocouple temperature sensor into a digital temperature value and transmits the digital temperature value to the microprocessor;

the first temperature detector is connected with the microprocessor through a single data bus and transmits the acquired temperature value to the microprocessor; the detection range of the first temperature detector is-55 ℃ to +125 ℃;

the second temperature detector is electrically connected with the microprocessor and transmits the acquired data to the microprocessor; the detection range of the second temperature detector is-55 ℃ to +150 ℃, and high impedance is output.

2. The ambient temperature monitoring device for a launch vehicle according to claim 1, wherein said first switch is a MAX31865 chip, a pin SCLK of said MAX31865 chip is connected to a pin CLK of said SPI bus, a pin SDI of said MAX31865 chip is connected to a pin SIMO of said SPI bus, and a pin SDO of said MAX31865 chip is connected to a pin SOMI of said SPI bus;

the resistance type temperature sensor is PT100, and the PT100 can be connected with the MAX31865 chip by adopting a two-wire system or three-wire system or four-wire system connection mode.

3. The ambient temperature monitoring device for a launch vehicle of claim 1, wherein the second switch is a MAX31856 chip, pin SCK of the MAX31856 chip is coupled to pin CLK of the SPI bus, pin SDI of the MAX31856 chip is coupled to pin SIMO of the SPI bus, and pin SDO of the MAX31856 chip is coupled to pin SOMI of the SPI bus;

the MAX31856 chip is connected with the thermocouple temperature sensor in a twisted mode through a shielding cable, temperature lookup tables of thermocouples with different division numbers are integrated in the MAX31856 chip, and the temperature lookup tables conduct nonlinear correction on temperature data collected by the thermocouple temperature sensor.

4. The ambient temperature monitoring apparatus for a launch vehicle of claim 1, wherein said first temperature detector is a DS18B20 digital temperature sensor, and a plurality of said DS18B20 digital temperature sensors can be connected in parallel on a single data bus to achieve multi-point temperature measurement.

5. The ambient temperature monitoring apparatus for a launch vehicle of claim 1, wherein the second temperature detector is an AD590 temperature sensor, a positive terminal of the AD590 temperature sensor being electrically connected to the microprocessor, and a negative terminal of the AD590 temperature sensor being grounded.

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