High-sampling-rate temperature monitoring device and method and high-sampling-rate temperature monitoring system for superconducting magnet
By combining signal acquisition, preprocessing, and temperature compensation modules, the problem of sensor thermal response delay in superconducting magnet temperature monitoring is solved, enabling rapid and accurate temperature monitoring at high sampling rates and meeting the requirements for stable operation and quench warning of superconducting magnets.
Patent Information
- Application Number
- CN202511788472.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-02-13
AI Technical Summary
Existing high-sampling-rate temperature monitoring equipment suffers from sensor thermal response delay in extremely low-temperature environments, resulting in delayed sampling data and large measurement errors, which cannot meet the requirements for quench warning of superconducting magnets.
By employing a signal acquisition module, a signal preprocessing module, and a temperature compensation module, combined with a Cernox temperature sensor, an ADS1248 chip, and a DSP chip, and using a temperature compensation formula and a resistance-temperature calibration table, temperature monitoring at high sampling rates is achieved, eliminating the effects of thermal response delay.
At high sampling rates, measurement errors are reduced, enabling rapid and accurate temperature monitoring to meet the stable operation requirements of superconducting magnets and ensure imaging quality and diagnostic reliability.
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Figure CN121521285A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of temperature sensing detection, and particularly relates to a high-sampling-rate temperature monitoring device and method and a high-sampling-rate temperature monitoring system for a superconducting magnet. BACKGROUND
[0002] Superconducting magnets have become an indispensable part of modern scientific and technological development, and their working principle is based on the characteristics of superconducting materials showing zero resistance and complete diamagnetism under certain low-temperature conditions, playing a key role in many fields. Since the superconducting characteristics of superconducting materials must be under certain low-temperature conditions, once the temperature exceeds the critical temperature of the superconducting material, the superconducting magnet will lose superconductivity, i.e., transition from the superconducting state to the normal state, which will cause a series of serious problems. Therefore, fast and accurate temperature monitoring is crucial for the reliable operation of superconducting magnets.
[0003] When the superconducting magnet is running, the temperature change is often extremely rapid and subtle, and ordinary sampling rate monitoring equipment may not be able to detect these key temperature fluctuations in time. High-sampling-rate equipment can sample the temperature of the superconducting magnet at a very high frequency, thereby accurately capturing the instantaneous change in temperature. However, this process requires matching the fast thermal response capability of the sensor and the high-efficiency data processing capability - there is a significant thermal response delay of the sensor under extremely low-temperature conditions (such as the Cernox1050 model sensor with a delay time of 1.5 ms under 4.2K working conditions), which easily leads to lagging of the sampling data, and the measurement error of the traditional non-compensation scheme is large, which cannot meet the actual needs of superconducting magnet quenching early warning.
[0004] High-sampling-rate has irreplaceable key significance in superconducting magnet temperature monitoring, and its core value lies in its ability to quickly capture the instantaneous change in temperature, providing timely and effective protection for the safe and stable operation of superconducting magnets. Taking the superconducting magnetic resonance imaging equipment in the medical field as an example, high-sampling-rate temperature monitoring equipment can ensure that the superconducting magnet is always at a stable operating temperature, ensuring the stability and accuracy of the imaging quality and providing reliable basis for doctors' diagnosis.
[0005] Taking the lakeshore 218 temperature measuring instrument as an example, single-channel one-second data collection is performed sixteen times, but this process requires matching the fast thermal response capability of the sensor and the high-efficiency data processing capability - there is a significant thermal response delay of the sensor under extremely low-temperature conditions (such as the Cernox1050 model sensor with a delay time of 1.5 ms under 4.2K working conditions), which easily leads to lagging of the sampling data, and the measurement error of the traditional non-compensation scheme is large, which cannot meet the actual needs of superconducting magnet quenching early warning. SUMMARY
[0006] The application aims to provide a high sampling rate temperature monitoring device, method and high sampling rate temperature monitoring system for superconducting magnets, which can eliminate the influence of thermal response delay through temperature compensation and reduce measurement error under high frequency sampling.
[0007] To achieve the above-mentioned purpose, the application provides a high sampling rate temperature monitoring device in the first aspect, which comprises a signal acquisition module, a signal preprocessing module and a temperature compensation module. The signal acquisition module comprises a temperature sensor, an analog-digital conversion unit and a data storage unit, the temperature sensor is used to acquire temperature signals of an environment to be measured, the analog-digital conversion unit is used to convert the temperature signals into digital signals, and the data storage unit is used to store the digital signals according to time labels. The signal preprocessing module is used to convert the digital signals to obtain an initial temperature value T0 at the current time, and the signal acquisition and processing frequencies of the signal acquisition module and the signal preprocessing module are both greater than or equal to 500 Hz. The temperature compensation module is used to perform temperature compensation according to the following formula to obtain a real temperature value T at the current time comp :
[0008]
[0009] Wherein, τ is the thermal response delay time of the temperature sensor, and the unit is ms; is the temperature change rate, and the unit is K / ms; T is the initial temperature value at the last time of , and the unit is K; is the initial temperature value at the last time of , and the unit is K; Ts is the signal acquisition period, and the unit is ms.
[0010] Further, the data storage unit also stores a resistance-temperature calibration table in the temperature range of 4.2K-20K; the initial temperature value T0 at the current time is obtained by querying the resistance-temperature calibration table.
[0011] Further, the signal preprocessing module performs zero-point calibration and gain calibration on the digital signals to obtain a corrected voltage value U, and then obtains the resistance according to the current of the temperature sensor.
[0012] Further, the temperature sensor is a Cernox temperature sensor, the thermal response delay time τ of the Cernox temperature sensor is 1.5 ms; and the temperature change range of the environment to be measured is 4.2K-20K.
[0013] Furthermore, the high sampling rate temperature monitoring device also includes a constant current source module, which is used to excite the microampere-level current output of the Cernox temperature sensor through operational amplifier feedback adjustment.
[0014] Furthermore, the analog-to-digital conversion unit uses an ADS1248 chip, the signal preprocessing module uses a DSP chip, and the RAM of the DSP chip has a three-point historical data buffer area, into which the digital signal is stored.
[0015] A second aspect of the present invention provides a high sampling rate temperature monitoring method, comprising the following steps: The temperature sensor acquires the temperature signal of the environment under test at a sampling frequency of 500 Hz or higher. The temperature signal is converted into a digital signal and stored according to a time stamp; The digital signal is converted to obtain the initial temperature value T0 at the current moment; The current true temperature value T is obtained by performing temperature compensation on the initial temperature value T0 according to the following formula. comp :
[0016]
[0017] Where τ is the thermal response delay time of the temperature sensor, in milliseconds; This is the rate of temperature change, expressed in K / ms. for The initial temperature value at the previous moment, in K; for The initial temperature value at the previous moment, in K; Ts is the signal acquisition period, in ms.
[0018] Furthermore, the specific steps include: When the Cernox temperature sensor is placed in the environment to be measured, the ADS1248 chip starts the ADC conversion, which converts the analog voltage signal output by the Cernox temperature sensor into a digital signal after being amplified by the PGA in real time. The ADS1248 chip sends a ready signal to the DSP chip through the DRDY pin. The DSP chip reads the digital signal through the SPI interface, and then performs zero-point calibration and gain calibration on the digital signal to obtain the corrected voltage value U. The resistance is obtained from the current, and the corresponding initial temperature value T0 is obtained from the resistance-temperature calibration table; finally, the actual temperature value is obtained from the temperature compensation.
[0019] Furthermore, when the temperature change rate When the temperature compensation is not used, the initial temperature value T0 is directly output as the true value, and the start time of temperature compensation is greater than or equal to 3ms.
[0020] A third aspect of the present invention provides a high sampling rate temperature monitoring system for a superconducting magnet, comprising a superconducting magnet, a cryogenic cooling module, and the high sampling rate temperature monitoring device described in any one of the above. The cryogenic cooling module is used to create a cryogenic environment for the superconducting magnet, and the temperature sensor of the high sampling rate temperature monitoring device is set in the cryogenic environment; the temperature of the cryogenic environment is lower than the critical temperature of the superconducting magnet.
[0021] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. The high sampling rate temperature monitoring device provided by the present invention, through joint improvement of software and hardware, eliminates the influence of thermal response delay of temperature sensor by temperature compensation under the condition of high-speed sampling, reduces measurement error, and achieves fast and accurate temperature monitoring.
[0022] 2. This invention is based on the collaborative design of DSP and ADS1248, combined with the optimization of Cernox1050 sensor characteristics. Firstly, a 1µA current source is used at 4.2K to reduce self-heating interference. At the same time, the built-in PGA amplifier of ADS1248 is set to a gain of 128 times to amplify the weak 5mV signal to 640mV, ensuring a signal-to-noise ratio of ≥82dB, thus solving the problem of insufficient signal strength under low current excitation.
[0023] 3. This invention uses a "pre-calibration lookup table + linear interpolation iterative compensation" scheme to replace the traditional Chebyshev polynomial fitting method, which greatly improves the data processing speed. The temperature change rate is derived by "current sampled value + previous two frames of historical sampled data", and the 1.5ms thermal response delay is gradually eliminated through iterative compensation, avoiding the problem of asynchronous sampling and response.
[0024] 4. This invention not only meets the monitoring requirements of superconducting magnet experiments in low-temperature environments (4.2K-20K), but also maintains a measurement accuracy of ±0.05K under high sampling rate conditions by utilizing a high-precision sampling chip and optimized algorithms, thus meeting the technical requirements of high-speed and fast-response temperature acquisition in superconducting magnet quenching experiments. Compared with traditional temperature monitoring equipment, this invention significantly improves the sampling rate and response speed.
[0025] 5. This invention can be used for high sampling rate temperature monitoring of superconducting magnets, can be used in low-temperature environments for superconducting magnet experiments, and can meet the requirements for rapid acquisition and response in quenching experiments. It can provide early warning in the early stage of quenching, and can also respond quickly to temperature fluctuations caused by other non-quenching conditions, so as to make timely responses. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 The component block diagram of the high sampling rate temperature monitoring device of the present application; Figure 2 The control flow chart of the data acquisition module and the DSP chip; Figure 3 The connection circuit schematic diagram of the ADS1248 chip and the DSP chip; Figure 4 The temperature-resistance fitting curve diagram of the Cernox sensor; Figure 5 The flow chart of the high sampling rate temperature monitoring method of the present application; Figure 6 The schematic diagram of the external machine of the present application. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.
[0028] Please refer to Figures 1-6 The present application provides a high sampling rate temperature monitoring device, comprising a signal acquisition module, a signal preprocessing module and a temperature compensation module; The signal acquisition module comprises a temperature sensor, an analog-to-digital conversion unit and a data storage unit, the temperature sensor is used to acquire the temperature signal of the environment to be measured; the analog-to-digital conversion unit is used to convert the temperature signal into a digital signal; the data storage unit is used to store the digital signal according to the time tag; The signal preprocessing module is used to convert the digital signal to obtain the initial temperature value T0 at the current time; the signal acquisition and processing frequency of the signal acquisition module and the signal preprocessing module are both greater than or equal to 500Hz; The temperature compensation module is used to compensate the temperature according to the following formula to obtain the real temperature value T at the current time comp :
[0029]
[0030] Wherein, τ is the thermal response delay time of the temperature sensor, the unit is ms; is the temperature change rate, the unit is K / ms; is the initial temperature value at the last time of T , the unit is K. T0 is the initial temperature value of the last time, and the unit is K; Ts is the signal acquisition period, and the unit is ms. T0 is the initial temperature value of the last time, and the unit is K; Ts is the signal acquisition period, and the unit is ms.
[0031] The signal acquisition and processing frequency of the application is preferably 800-1200Hz, for example 1000Hz, and the acquisition period is 1ms. Because the sampling rate is very fast, the temperature sensor has a deviation between the sensed temperature and the real temperature due to the thermal response time. Therefore, the application performs temperature compensation based on the temperature change rate to reduce the difference between the output temperature and the real temperature of the environment and improve the detection accuracy.
[0032] The data storage unit also stores a resistance-temperature calibration table in the temperature interval of 4.2K-20K; and the initial temperature value T0 of the current time is obtained by querying the resistance-temperature calibration table. The application is mainly designed for low-temperature superconducting magnet temperature monitoring, and is mainly suitable for monitoring in the temperature interval of 4.2K-20K. The temperature compensation method of the application in this interval is simple, fast and relatively high in accuracy.
[0033] The signal preprocessing module performs zero point calibration and gain calibration on the digital signal to obtain a corrected voltage value U, and then obtains the resistance according to the current of the temperature sensor.
[0034] Further, the temperature sensor is a Cernox temperature sensor, and the thermal response delay time τ of the Cernox temperature sensor is 1.5ms.
[0035] The high sampling rate temperature monitoring device further comprises a constant current source module for realizing excitation output of the microampere-level current of the Cernox temperature sensor through operational amplifier feedback adjustment.
[0036] The analog-to-digital conversion unit adopts an ADS1248 chip, the signal preprocessing module adopts a DSP chip, the RAM of the DSP chip is provided with a three-point historical data buffer area, and the digital signal is stored in the three-point historical data buffer area.
[0037] The second aspect of the application provides a high sampling rate temperature monitoring method, comprising the following steps: The temperature sensor collects the temperature signal of the environment to be measured at a sampling frequency greater than or equal to 500Hz; The temperature signal is converted into a digital signal and stored according to a time tag; The digital signal is converted to obtain the initial temperature value T0 of the current time; The initial temperature value T0 is temperature-compensated according to the following formula to obtain the real temperature value T of the current time comp :
[0038]
[0039] Wherein, τ is the temperature sensor thermal response delay time, unit is ms; is the temperature change rate, unit is K / ms; is the initial temperature value of the last time of T, unit is K; is the initial temperature value of the last time of T, unit is K; Ts is the signal acquisition period, unit is ms. is the initial temperature value of the last time of T, unit is K; Ts is the signal acquisition period, unit is ms. is the initial temperature value of the last time of T, unit is K; Ts is the signal acquisition period, unit is ms.
[0040] Further, specifically comprising the following steps: The Cernox temperature sensor is placed in the environment to be measured, the ADS1248 chip starts the ADC conversion, and the analog voltage signal output by the Cernox temperature sensor is converted into a digital signal after PGA amplification in real time; The ADS1248 chip sends a ready signal to the DSP chip through the DRDY pin, the DSP chip reads the digital signal through the SPI interface, and then carries out zero point calibration and gain calibration on the digital signal to obtain the corrected voltage value U; According to the current, the resistance is obtained, and then the corresponding initial temperature value T0 is obtained according to the resistance-temperature calibration table; finally, the real temperature value is obtained according to the temperature compensation.
[0041] Further, when the temperature change rate is not used, and the initial temperature value T0 is directly output as the real value, and the starting time of the temperature compensation is greater than or equal to 3ms.
[0042] The third aspect of the present application provides a high sampling rate temperature monitoring system of a superconducting magnet, comprising a superconducting magnet, a low-temperature cooling module and the high sampling rate temperature monitoring device of any one of the above; The low-temperature cooling module is used for constructing a low-temperature environment for the superconducting magnet, and the temperature sensor of the high sampling rate temperature monitoring device is arranged in the low-temperature environment; the temperature of the low-temperature environment is lower than the critical temperature of the superconducting magnet.
[0043] The present application is further described in detail through specific embodiments.
[0044] The high sampling rate temperature monitoring device provided by the present application comprises a power supply module, a Cernox temperature sensor, a constant current source module, a data acquisition module and a temperature compensation module. The power supply module mainly supplies power for the constant current source module, the data acquisition module and the temperature compensation module. Here, the data acquisition module covers an analog-to-digital conversion unit, a data storage unit and a signal preprocessing module.
[0045] Cernox temperature sensor Cernox 1050 type sensor of Lakeshore company is selected, which can measure temperature as low as 4.2K and has a resistance change range of 10kΩ, meeting the monitoring demand of superconducting magnet in extremely low temperature scene. The resistance changes greatly in different temperature ranges, but the working voltage needs to be controlled within 10mV, so a constant current source module is needed to provide adjustable current excitation; The constant current source module is realized by operational amplifier feedback regulation, and cooperates with adjustable resistors to realize 1 microampere, 10 microamperes and 100 microamperes current excitation output, with an output precision of 0.03%, which ensures that the Cernox sensor works in the normal voltage range; meets the excitation demand of Cernox temperature sensor, and selects through the front panel button; The data acquisition module selects ADS1248 (24-bit high precision) as the analog-to-digital conversion chip, which supports a data rate of 2000SPS, can effectively collect the weak voltage signal (range 0~10mV) output by the Cernox sensor, and the ADS12148 is connected with the DSP according to the circuit shown in the figure. The DSP chip has a main frequency of 150Hz and has high-speed data operation capability, which can realize real-time voltage-resistance conversion and temperature fitting calculation, and communicates with the PC through the RS232 serial port. The data rate is configured to be 1000SPS by the DSP, and the data transmission can reach 1ms, while the traditional temperature monitoring equipment usually has a data rate of about 0.1s, and the sampling rate is much higher than that of the traditional detection equipment; the communication baud rate is set to 115200bps, which is much higher than the 9600bps of the traditional temperature detection equipment. Figure 3
[0046] The power supply module mainly outputs DC voltage: positive and negative 5V and positive and negative 15V, which powers the circuit to make it in normal working state.
[0047] The Cernox sensor connection adopts four-wire connection, two of which are connected to the output end of the constant current source module for current excitation, and the other two are connected to the differential input channel of ADS1248 for voltage signal transmission.
[0048] The DSP chip communicates with the ADS1248 through the SPI interface: configures the ADC sampling rate, amplification multiple and filter mode.
[0049] Further, the data acquisition and processing steps are as follows: (1) Initialization phase: After the device is powered on, the DSP first completes serial port initialization, SPI interface initialization, and ADS1248 register configuration. By writing instructions to the ADS1248 register, the amplification factor and sampling rate are set to 1000SPS, and filtering is enabled. At the same time, a "three-point historical data buffer area" is opened in the DSP's internal RAM, and the pre-stored 4.2K-20K "resistance-temperature" calibration table is loaded into the internal RAM. After initialization is completed, it enters standby mode and waits for sampling instructions.
[0050] (2) Signal acquisition stage: The DSP sends a sampling trigger command to the ADS1248 via SPI. The ADS1248 starts the ADC conversion, and the 5mV analog voltage signal output by the Cernox sensor is amplified by 128 times by the PGA (Programmable Gain Amplifier) and converted into a 640mV signal. Then the analog signal to digital signal conversion is completed. After the conversion is completed, the ADS1248 sends a ready signal to the DSP via the DRDY pin (pin level is pulled low). The DSP chip reads the digital signal through the SPI interface and updates the "three-point historical data buffer" (newly acquired data is stored in the T0 storage bit, the original T0 data is moved to the T1 storage bit, and the original T1 data is moved to the T2 storage bit). The time for a single acquisition can be controlled within 1ms.
[0051] (3) Data preprocessing stage: The DSP performs zero-point calibration and gain calibration on the acquired digital signal to obtain the corrected voltage value U.
[0052] (4) The temperature conversion and thermal response compensation steps are as follows: (401) Resistance calculation: The DSP identifies the current level of the constant current source module through the DSP pin and calculates the real-time resistance value R of the Cernox sensor using formula (1):
[0053] In the formula, This is the voltage of the temperature sensor. For the current excitation of the temperature sensor, This is the resistance value of the temperature sensor.
[0054] (402) Lookup table location: The DSP chip locates the two adjacent data points corresponding to the real-time resistance R in the pre-stored "resistance-temperature" calibration table using a binary search method. , )and( , ),in These are the temperature data corresponding to the resistance values; when there is no resistor R in the "resistance-temperature" calibration table, the temperature corresponding to R can be estimated based on R1 and R2.
[0055] Cernox sensor is a negative temperature coefficient sensor, so Chebyshev polynomial is selected for least square fitting for calibration fitting. According to formula (2) for fitting: (2) In the formula, T is the temperature; R is the sensor resistance; is the fitting coefficient; A, B are normalization constants, calculated according to formula (3) and formula (4); are the maximum and minimum values of the resistance value respectively.
[0056] (3) (4) According to the resistance-temperature fitting curve in Figure 3 , the DSP selects the corresponding fitting formula for temperature conversion, and calculates the corresponding temperature value.
[0057] (403) Linear interpolation iterative compensation: Core parameter definition: sampling period , sensor thermal response delay time , temperature change rate under typical quench scenario , historical sampling data includes (current sensor output value), (1ms sampling output value), (2ms sampling output value).
[0058] Calculate the uncompensated error (quench scenario example): assume when the superconducting magnet starts to quench, the real temperature changes with time as , then , the real temperature , the sensor output value in the uncompensated state , the uncompensated error percentage is calculated to be about 43.9%.
[0059] Compensation formula derivation: estimate the temperature change rate from the historical sampling data, the calculation formula is (where is the sampling period), on this basis, superimpose the temperature increment in the lag time to get the real temperature value after compensation, the specific formula is ; In the formula: is the current real temperature value after compensation, is the estimated temperature change rate (unit: ), is the sensor thermal response delay time.
[0060] Single compensation effect verification: take For example, At this time, the temperature change rate is calculated , and the compensation formula is obtained At this time, the measurement error is reduced to 21.9%; Iterative compensation optimization: the single compensation result T comp (t) is taken as the historical data for the next round of compensation calculation (updating the T1 storage bit data), when t = 4ms, , It can be seen that after iterative compensation, the temperature change rate estimation value gradually converges to the true value (10K / ms), which also shows that the present application is more suitable for short-time and rapid temperature accurate monitoring, and can accurately monitor and warn in the working temperature range interval of the superconducting magnet.
[0061] The DSP converts the calculated temperature value into decimal for display, and sends it to the PC host computer through the RS232 serial port for auxiliary analysis and processing.
[0062] The host computer acquisition process is as follows: (1) Host computer initialization: running Labview on the PC, completing serial connection, setting baud rate and data format.
[0063] (2) Data receiving and storage: the host computer receives the temperature data sent by the DSP through the serial port in real time, and automatically stores the data to the table, while real-time drawing temperature-time curve.
[0064] The main panel of the external device is composed of a display screen and buttons, and the display screen displays the temperature and resistance of the channel, and the buttons control the output current source size; the back version is mainly composed of an RS232 interface, a sensor interface and a power supply interface, mainly realizing the connection of the sensor and the connection with the PC end of the host computer.
[0065] Further, the engineering implementation logic of the linear interpolation iterative compensation algorithm is as follows: (1) Historical data caching mechanism: the 3-point data cache area of the DSP chip is updated in real time, and each temperature data is stored in 8-byte floating-point format; (2) Compensation trigger condition setting: the compensation algorithm is started by default from the third sampling (t = 3ms), and the first two samplings only complete data storage, ensuring that there is enough historical data for temperature change rate calculation; (3) Abnormal processing strategy: when the estimated temperature change rate (static or slow temperature change scenario), the compensation algorithm is automatically disabled, and the temperature value output by the lookup table is directly used, avoiding additional measurement error introduced by interpolation operation; when (temperature abnormal sudden change, which may be sensor failure), an alarm signal is immediately triggered and the current measurement data is locked.
[0066] In summary, in order to overcome the defects of low sampling rate, long data processing time, obvious sensor thermal response delay and the like of the conventional temperature monitoring device, the application provides a high sampling rate temperature monitoring device, method and high sampling rate temperature monitoring system for superconducting magnets, which is based on the joint design of DSP and ADS1248, combines the characteristics of Cernox1050 sensor, adopts the optimization technical scheme of "adjustable constant current excitation + built-in PGA amplification of ADS1248 + pre-calibration lookup table + linear interpolation iterative compensation", constructs a combined optimization monitoring system with complementary advantages, improves the sampling rate of the temperature monitoring device to hundreds or even thousands of times per second, shortens the data processing time, eliminates the 1.5ms thermal response delay through the iterative compensation algorithm, and reduces the measurement error.
[0067] Those skilled in the art will readily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A high sampling rate temperature monitoring device, characterized in that, It includes a signal acquisition module, a signal preprocessing module, and a temperature compensation module; The signal acquisition module includes a temperature sensor, an analog-to-digital converter, and a data storage unit. The temperature sensor is used to acquire the temperature signal of the environment under test; the analog-to-digital converter is used to convert the temperature signal into a digital signal; and the data storage unit is used to store the digital signal according to a time stamp. The signal preprocessing module is used to convert the digital signal to obtain the initial temperature value T0 at the current moment; the signal acquisition and processing frequencies of both the signal acquisition module and the signal preprocessing module are greater than or equal to 500Hz; The temperature compensation module is used to perform temperature compensation according to the following formula to obtain the true temperature value T at the current moment. comp : Where τ is the thermal response delay time of the temperature sensor; This represents the rate of change of temperature over time. for The initial temperature value at the previous moment; for The initial temperature value at the previous moment; Ts is the signal acquisition period.
2. The high sampling rate temperature monitoring device according to claim 1, characterized in that, The data storage unit also stores a resistance-temperature calibration table within the temperature range of 4.2K-20K; the initial temperature value T0 at the current moment is obtained by querying the resistance-temperature calibration table.
3. The high sampling rate temperature monitoring device according to claim 2, characterized in that, The signal preprocessing module performs zero-point calibration and gain calibration on the digital signal to obtain the corrected voltage value U, and then obtains the resistance based on the current of the temperature sensor.
4. The high sampling rate temperature monitoring device according to claim 1, characterized in that, The temperature sensor is a Cernox temperature sensor, and the thermal response delay time τ of the Cernox temperature sensor is 1.5ms; the temperature range of the environment to be measured is 4.2K-20K.
5. The high sampling rate temperature monitoring device according to claim 4, characterized in that, The high sampling rate temperature monitoring device also includes a constant current source module, which is used to excite the microampere-level current output of the Cernox temperature sensor through operational amplifier feedback adjustment.
6. The high sampling rate temperature monitoring device according to any one of claims 1-5, characterized in that, The analog-to-digital conversion unit uses an ADS1248 chip, and the signal preprocessing module uses a DSP chip; the RAM of the DSP chip has a three-point historical data buffer area, and the digital signal is stored in the three-point historical data buffer area.
7. A high sampling rate temperature monitoring method, characterized in that, Includes the following steps: The temperature sensor acquires the temperature signal of the environment under test at a sampling frequency of 500 Hz or higher. The temperature signal is converted into a digital signal and stored according to a time stamp; The digital signal is converted to obtain the initial temperature value T0 at the current moment; The current true temperature value T is obtained by performing temperature compensation on the initial temperature value T0 according to the following formula. comp : Where τ is the thermal response delay time of the temperature sensor; This represents the rate of change of temperature over time. for The initial temperature value at the previous moment; for The initial temperature value at the previous moment; Ts is the signal acquisition period.
8. The high sampling rate temperature monitoring method according to claim 7, characterized in that, Specifically, the following steps are included: When the Cernox temperature sensor is placed in the environment to be measured, the ADS1248 chip starts the ADC conversion, which converts the analog voltage signal output by the Cernox temperature sensor into a digital signal after being amplified by the PGA in real time. The ADS1248 chip sends a ready signal to the DSP chip through the DRDY pin. The DSP chip reads the digital signal through the SPI interface, and then performs zero-point calibration and gain calibration on the digital signal to obtain the corrected voltage value U. The resistance is obtained from the current, and the corresponding initial temperature value T0 is obtained from the resistance-temperature calibration table; finally, the actual temperature value is obtained from the temperature compensation.
9. The high sampling rate temperature monitoring method according to claim 7 or 8, characterized in that, When the temperature change rate When the temperature compensation is not used, the initial temperature value T0 is directly output as the true value, and the start time of temperature compensation is greater than or equal to 3ms.
10. A high sampling rate temperature monitoring system for superconducting magnets, characterized in that, Includes a superconducting magnet, a cryogenic cooling module, and a high sampling rate temperature monitoring device as described in any one of claims 1-6; The cryogenic cooling module is used to create a cryogenic environment for the superconducting magnet, and the temperature sensor of the high sampling rate temperature monitoring device is set in the cryogenic environment; the temperature of the cryogenic environment is lower than the critical temperature of the superconducting magnet.