Temperature Compensation Research Articles

Temperature Compensation of Low-cost Sensors for Accurate Temperature Measurement

Evapotranspiration (ET) is a critical process in agricultural system. ET states the combined water loss from the soil and plant surfaces. Predicting ET is vital for effective water resource management. Accurate temperature and humidity measurements is instrumental in calculating Et. Temperature measurement plays a key role in various industrial, scientific, and agricultural applications. The study investigates the performance of three temperature humidity sensors. DHT11, DHT22 and LM35. The sensors are analyzed under different conditions, including compensation, and with a temperature compensation algorithm, and with proportional P and proportional-integral-derivative PID controllers. Sensors are interfaced with a Raspberry Pi 4B model. The sensors were tested in controlled environments with temperatures ranging from 10 degrees to 100 degrees C, and their accuracy was evaluated by comparing their outputs with the reference values. Results revealed that the error percentages for all sensors exceeded permissible limits when used outside their specified ranges. Incorporating temperature compensation algorithm and P and PID controllers significantly improved measurement accuracy, reducing error percentages and root mean square errors (RMSE) across all sensors. Out of the three sensors, LM35 demonstrated a 5-fold reduction in error percentage at higher temperatures compared to other methods. The improved sensor accuracy has significant implications for agricultural applications such as ET calculation, where precise temperature data is necessary. Reducing error enhances better agricultural water management strategies and overall productivity.

Investigation on the temperature dependence and mechanism of conductive behavior of conductive natural rubber composite with negative temperature coefficient

AbstractConductive polymer composites (CPCs) often face complex service‐temperature problems. To systematically investigate the influence of temperature on the electrical conductivity and sensing behavior of CPCs, multiwalled carbon nanotube (MWCNT)/natural rubber (NR) composites were studied herein. The research results showed that within the temperature range of −20°C to 60°C, the MWCNT/NR composites had a negative temperature coefficient. Their conductive behavior strengthened with increasing temperature; thus, the composites showed good temperature cycling stability. Increasing temperature was beneficial for the improvement of the monotonicity and symmetry of the resistance–strain response of the composites and the shoulder peak phenomenon. Between 0°C and 60°C, their resistance was less affected by temperature changes and the internal‐charge conduction mechanism was ohmic conduction. Compared with applied voltage and generated strain, temperature more notably influenced charge transport in the composites. Through analytical testing and coarse‐grained molecular dynamics simulation, the systematic mechanism underlying the influence of temperature on the electrical conductivity and sensing behavior of the MWCNT/NR composites was revealed. Further, the influence of thermal expansion and thermal fluctuations on the electrical conductivity of the MWCNT/NR composites was discussed, indicating that thermal fluctuation plays a dominant role. Overall, this research lays a solid foundation for eliminating temperature interference in the sensing response of MWCNT/NR composites and optimizing their sensing response accuracy.Highlights Exploring the relationship between temperature and sensing behavior of MWCNT/NR. Revealing the influence mechanism of temperature on the sensing of MWCNT/NR. MWCNT/NR exhibits cyclic, stable sensing behavior with negative coefficient. Stable sensing response significant for temperature compensation.

Theoretical and experimental investigations of the CMOS compatible Pirani gauges with a temperature compensation model

In this article, a CMOS-compatible Pirani vacuum gauge was proposed featuring enhanced sensitivity, lower detection limit, and high-temperature stability, achieved through the implementation of a surface micromachining method coupled with a temperature compensation strategy. To improve performance, a T-type device with a 1 µm gap was fabricated resulting in an average sensitivity of 1.10 V/lgPa, which was 2.89 times larger than that (0.38 V/lgPa) of a L-type device with a 100 µm gap. Additionally, FEA simulations were conducted, analyzing the influence of heater temperature on sensitivity and the attenuation of sensitivity across varying ambient temperatures. A semi-empirical theoretical mode was derived for performance prediction, demonstrating strong alignment with experimental results, underscoring its effectiveness in compensating for sensitivity attenuation. Building on the foundation, the device’s performance under different ambient temperatures was characterized and effectively compensated in two distinct operational modes: constant temperature mode and constant temperature difference mode (the whole range temperature compensation error can be controlled within 2.5%). Finally, the short-time stability (variation level is approximately 1 mV), noise floor (Vrms=384 μV) and detection limit (0.07 Pa @1 Hz) of the device were characterized, confirming its suitability for practical implementation.

Circadian gating: concepts, processes, and opportunities.

Circadian clocks provide a biological measure of time that coordinates metabolism, physiology and behaviour with 24 h cycles in the environment. Circadian systems have a variety of characteristic properties, such as entrainment to environmental cues, a self-sustaining rhythm of about 24 h and temperature compensation of the circadian rhythm. In this perspective, we discuss the process of circadian gating, which refers to the restriction of a biological event to particular times of day by the circadian clock. We introduce principles and processes associated with circadian gating in a variety of organisms, including some associated mechanisms. We highlight socioeconomic opportunities presented by the investigation of circadian gating, using selected examples from circadian medicine and agricultural crop production to illustrate its importance.This article is part of the Theo Murphy meeting issue 'Circadian rhythms in infection and immunity'.

Erbium: key to simultaneously achieving superior temperature-stability and high magnetic properties in 2 : 17-type permanent magnets.

To address the demands of rapidly advancing precision instruments requiring higher efficiency and miniaturization, permanent magnets must exhibit exceptional energy density, temperature stability, high magnetic energy product [(BH)max], and adequate coercivity (Hcj). Herein, we design rare earth Er-based magnets (2 : 17-type Er-magnets) with a composition of (Er, Sm)(Co, Fe, Cu, Zr)7.6. Erbium-based compounds (Er2Co17) offer a unique combination of temperature compensation and high saturation magnetization compared to other heavy rare earth elements, resulting in 2 : 17-type Er-magnets with superior temperature stability in Br and (BH)max. Partially substituting Sm reduces the energy barrier for the 2 : 17H-to-2 : 17R phase transition, promoting the development of a complete cellular structure and achieving enhanced coercivity. Notably, the optimal performance is obtained with Er constituting 60% of the total rare earth content, delivering a near-zero temperature-coefficient for Br and (BH)max within 20-150 °C while maintaining Br at 8.92 kG, Hcj at 29.83 kOe, and (BH)max at 18.5 MGOe. These 2 : 17-type Er-magnets provide valuable insights for developing permanent magnets with exceptional comprehensive properties.

System-level modeling with temperature compensation for a CMOS-MEMS monolithic calorimetric flow sensing SoC

We present a system-level model with an on-chip temperature compensation technique for a CMOS-MEMS monolithic calorimetric flow sensing SoC. The model encompasses mechanical, thermal, and electrical domains to facilitate the co-design of a MEMS sensor and CMOS interface circuits on the EDA platform. The compensation strategy is implemented on-chip with a variable temperature difference heating circuit. Results show that the linear programming for the low-temperature drift in the SoC output is characterized by a compensation resistor Rc with a resistance value of 748.21 Ω and a temperature coefficient of resistance of 3.037 × 10−3 °C−1 at 25 °C. Experimental validation demonstrates that within an ambient temperature range of 0–50 °C and a flow range of 0–10 m/s, the temperature drift of the sensor is reduced to ±1.6%, as compared to ±8.9% observed in a counterpart with the constant temperature difference circuit. Therefore, this on-chip temperature-compensated CMOS-MEMS flow sensing SoC is promising for low-cost sensing applications such as respiratory monitoring and smart energy-efficient buildings.

A Temperature Compensation Algorithm for Digital Temperature Measurement of Main Transformer Based on BPNN

A Temperature Compensation Algorithm for Digital Temperature Measurement of Main Transformer Based on BPNN

Temperature compensation study of pressure sensors after leadless packaging

Purpose The purpose of this paper is to reduce the problem of temperature drift causing output errors in such sensors, three hardware compensation schemes are proposed in this paper, and three compensation schemes are designed and implemented. Design/methodology/approach In response to the problem of temperature drift causing output errors in this type of sensor, this paper proposes three hardware compensation schemes and carries out the design and implementation of the three compensation schemes. Finally, the advantages and disadvantages of the three compensation schemes are discussed through the analysis of the experimental results. The three hardware compensation methods are series-parallel resistance network compensation, digital signal processor (DSP) compensation and the joint compensation of resistance network and DSP. Series parallel resistance network compensation is to connect the low-temperature drift resistance and the sensor in series and parallel; DSP compensation is based on the combination of cubic spline interpolation and linear fitting algorithm, which uses DSP to process the data. Joint compensation is a new compensation method composed of the above two compensation methods. Findings The experimental results show that the relative error of the output is reduced to a certain extent after the three compensation methods, and the relative error of the output after the joint compensation is reduced to about 0.2%, which proves that the three compensation methods are feasible. Originality/value This paper presents three novel hardware compensation methods to reduce temperature drift in silicon on insulator (SOI) high-temperature pressure sensors. The joint compensation method, combining resistance network and DSP compensation, is particularly innovative and significantly improves output accuracy, reducing relative error to about 0.2%.

Miniaturized inertial sensor based on high-resolution dual atom interferometry.

Atom interferometry shows high sensitivity for inertial measurements in the laboratory, but it faces difficulties in field applications because of a trade-off between sensitivity and size. Therefore, there is an urgent need to develop a small sensor with high resolution for measuring acceleration and rotation in inertial navigation applications. Presented here is a miniaturized inertial sensor capable of measuring acceleration and rotation simultaneously based on high-resolution dual atom interferometers. A sensor head is integrated within a volume of 100 l, in which the vacuum chambers are fabricated by bonding quartz-glass windows with epoxy resin. A photoelectric cabinet is composed of four 3U rack units by integrating optical modules and electronic units. Dual atom interference fringes with a contrast of 29% are observed, and the acceleration and rotation are measured simultaneously by extracting their phase shifts. By developing a temperature compensation method to eliminate phase drifts caused by the thermal deformation of the Raman mirrors and using wave vector reversal to eliminate the phase drifts independent of the direction of the wave vector, measurement resolutions of 40 ng at 518s and 6.1 nrad/s at 10 880s are achieved for acceleration and rotation, respectively, from Allan deviations.

Temperature compensation for quartz flexible accelerometer based on IAPSO-RBF

Temperature compensation for quartz flexible accelerometer based on IAPSO-RBF

Solution Temperature Compensation Factor for the Measured pH Value of Cement‐Based Materials

Most of the conventional pH measurements were carried out in acidic to slightly alkaline solutions. In this pH range, the effect of temperature during the measurement is negligible and can be ignored. However, the pH value for highly alkaline solutions is considerably sensitive to their temperature change. A slight difference in temperature can affect the accuracy of the pH test result. Cement‐based materials (CBMs) are highly alkaline. The influence of temperature shall be minimised to compare the pH values of different CBMs precisely. In the literature related to pH measurement for CBMs, the solution temperature during the pH measurement was not recorded, whilst the room temperature recorded was in the range of 20°C–30°C. Therefore, solution temperature compensation (STC) shall be introduced into the pH measurement for CBMs to convert the measured pH into the pH value at a reference temperature of 25°C. To this end, firstly, the pH–temperature profile of the solutions was generated to identify the STC factor (fSTC, also known as solution temperature coefficient). Then, the solution temperature‐compensated pH (pHSTC) was calculated using fSTC to present the pH value in the reference temperature of 25°C. However, no standardised method exists for the generation of this pH–temperature profile. In this study, a simple method for generating pH–temperature profile and calculating pHSTC for CBMs was introduced.

A temperature compensation method for fiber Bragg gratings using negative thermal expansive β-eucryptite packaging

Abstract Fiber optic sensing measurements hold significant potential for various applications, but temperature compensation of fiber Bragg grating (FBG) remains a formidable challenge. This paper introduces the utilization of β-eucryptite as an encapsulation material for FBG, exploiting its negative thermal expansion property to achieve temperature compensation. A two-point adhesive sealing technique was employed to affix FBG to the β-eucryptite substrate. While bare FBG and sensors encapsulated in 7075 aluminum alloy served as comparison. Experimental outcomes reveal that the FBG encapsulated in β-eucryptite exhibits temperature sensitivities of 1.67 pm °C−1 within the temperature ranges of −30 °C to 150 °C. In contrast, bare FBG and sensor encapsulated with 7075 aluminum alloy display temperature sensitivities of 10.46 pm °C−1 and 37.31 pm °C−1, respectively. The use of β-eucryptite for sensor encapsulation effectively reduces the temperature sensitivity of FBG. This temperature compensation method is straightforward yet promising and has great potential in aerospace and precision instrument measurement.

A Novel Temperature Drift Compensation Algorithm for Liquid-Level Measurement Systems.

Aiming at the problem that ultrasonic detection is greatly affected by temperature drift, this paper investigates a novel temperature compensation algorithm. Ultrasonic impedance-based liquid-level measurement is a crucial non-contact, non-destructive technique. However, temperature drift can severely affect the accuracy of experimental measurements based on this technology. Theoretical analysis and experimental research on temperature drift phenomena are conducted in this study, accompanied by the proposal of a new compensation algorithm. Leveraging an external fixed-point liquid-level detection system experimental platform, the impact of temperature drift on ultrasonic echo energy and actual liquid-level height is examined. Experimental results demonstrate that temperature drift affects the speed and attenuation of ultrasonic waves, leading to decreased accuracy in measuring liquid levels. The proposed temperature compensation method yields an average relative error of 3.427%. The error range spans from 0.03 cm to 0.336 cm. The average relative error reduces by 21.535% compared with before compensation, showcasing its applicability across multiple temperature conditions and its significance in enhancing the accuracy of ultrasonic-based measurements.

Low cross-sensitivity and sensitivity enhanced FBG sensor based on OCMI with three cascaded FBGs.

This paper presents a highly sensitive, temperature-insensitive optical carrier microwave interferometry (OCMI) system using a cascaded three fiber Bragg grating (FBG) structure to generate an enhanced Vernier effect for sensing applications. The enhanced Vernier effect is created by superimposing the interferograms of two separate interferometers formed by pairing the sensing FBG with each reference FBG. Experimental and theoretical results show that in strain sensing, the sensitivity based on enhanced Vernier effect is -4.642 MHz/µε, which is 66.3 and 61.4 times higher than that of strain sensor based on two single interferometers used to generate the enhanced Vernier effect in this system respectively. Compared with the strain sensor based on traditional Vernier effect, this sensor has higher sensitivity, and in addition the amplification factor for measuring sensitivity can be easily adjusted by changing the spatial distance between the three cascade FBGs. Moreover, the temperature sensitivity is decreased from -38.318 MHz/°C to -71.384 kHz/°C with temperature compensation. The sensor exhibits high resolution, high sensitivity, and low cross-sensitivity, making it great potential for measuring small physical changes in complex environments.

Calibration of Marine Pressure Sensors with a Combination of Temperature and Pressure: A Case Study of SBE 37-SM

Accurate pressure measurement is crucial for understanding ocean dynamics in marine research. However, pressure sensors based on strain measurement principles are significantly affected by temperature variations, impacting the accuracy of depth measurements. This study investigates the SBE37-SM sensor and presents an improved calibration method based on a constant-pressure, variable-temperature scheme that effectively addresses temperature-induced deviations in pressure measurement. Experiments were conducted across a pressure range of 2000 dbar to 6000 dbar and a temperature range of 2 °C to 35 °C, establishing a comprehensive pressure–temperature calibration grid. The results show that, at a pressure of 6000 dbar, temperature-induced variations in readings for brand new SBE37-SM sensors can reach up to 9 dbar, while, for used sensors, they exceed 12 dbar, following a U-shaped trend. After applying a polynomial regression model for calibration, these variations were reduced to within ±0.5 dbar, significantly reducing the measurement uncertainty of the sensors in complex marine environments. This method underscores the necessity of further optimizing the CTD system’s temperature compensation mechanism during calibration and highlights the importance of regular calibration to minimize measurement uncertainty.

A Compensated Clock: Temperature and Nutritional Compensation Mechanisms Across Circadian Systems.

Circadian rhythms are ∼24-h biological oscillations that enable organisms to anticipate daily environmental cycles, so that they may designate appropriate day/night functions that align with these changes. The molecular clock in animals and fungi consists of a transcription-translation feedback loop, the plant clock is comprised of multiple interlocking feedback-loops, and the cyanobacterial clock is driven by a phosphorylation cycle involving three main proteins. Despite the divergent core clock mechanisms across these systems, all circadian clocks are able to buffer period length against changes in the ambient growth environment, such as temperature and nutrients. This defining capability, termed compensation, is critical to proper timekeeping, yet the underlying mechanism(s) remain elusive. Here we examine the known players in, and the current models for, compensation across five circadian systems. While compensation models across these systems are not yet unified, common themes exist across them, including regulation via temperature-dependent changes in post-translational modifications.

Sensitivity calibration method of FBG strain sensor in high and low temperature conditions

Abstract Strain and temperature sensitivity coefficients of fiber Bragg grating (FBG) sensors are of vital importance to measuring accuracy, especially in varying temperature conditions. To improve the measurement accuracy of the FBG strain sensor, its strain and temperature sensitivity coefficients must be calibrated before use. In this study, we designed a substrate FBG strain sensor using the metal packaging method and illustrated its packaging process. A sensitivity calibration method for FBG strain sensors under different high-low temperatures was proposed. Additionally, an equal-intensity cantilever beam with the same material as the application structures of the FBG strain sensor, which affords loads within the range of −2500 to 3000 μϵ was designed and manufactured. A modified coefficient of strain δ was introduced to modify the strain results according to the calibration principle of an equal-intensity cantilever beam. Furthermore, a FBG unstressed temperature compensation method was proposed to compensate for the temperature of the FBG strain sensor. To verify the performance of the proposed sensitivity calibration method, a series of calibration experiments under −55 °C, −20 °C, 0 °C, 20 °C, 50 °C, and 70 °C were implemented, which proved the excellent performance of the proposed calibration method. Finally, the temperature and strain sensitivity coefficients of the FBG strain sensor in the temperature range of −55 °C to 70 °C are achieved at 0.3022 nm °C−1 and 0.5039 pm μϵ −1. The proposed sensitivity calibration method in high-low temperatures is simple and easy to implement. Meanwhile, the calibrated FBG strain sensor has prospective applications for strain measurement in structural health monitoring of aircraft, especially under varying temperature conditions.

Temperature-dependent fold-switching mechanism of the circadian clock protein KaiB

The oscillator of the cyanobacterial circadian clock relies on the ability of the KaiB protein to switch reversibly between a stable ground-state fold (gsKaiB) and an unstable fold-switched fold (fsKaiB). Rare fold-switching events by KaiB provide a critical delay in the negative feedback loop of this posttranslational oscillator. In this study, we experimentally and computationally investigate the temperature dependence of fold switching and its mechanism. We demonstrate that the stability of gsKaiB increases with temperature compared to fsKaiB and that the Q10 value for the gsKaiB → fsKaiB transition is nearly three times smaller than that for the reverse transition in a construct optimized for NMR studies. Simulations and native-state hydrogen-deuterium exchange NMR experiments suggest that fold switching can involve both partially and completely unfolded intermediates. The simulations predict that the transition state for fold switching coincides with isomerization of conserved prolines in the most rapidly exchanging region, and we confirm experimentally that proline isomerization is a rate-limiting step for fold switching. We explore the implications of our results for temperature compensation, a hallmark of circadian clocks, through a kinetic model.

Performance enhancement of mid-infrared NH3 sensor using 9.06 μm QCL based on spectral optimization and NGO-LSTM model.

A detection sensor for mid-infrared ammonia (NH3) has been developed according to wavelength modulation spectroscopy-tunable diode laser absorption spectroscopy (WMS-TDLAS) technology, which can be applied in the chemical and aquaculture industries. A9.06 µm quantum cascade laser (QCL) and a41.5 m multipass gas cell (MPGC) were used to increase the detection limit of NH3. Spectral optimization and theNGO-LSTM (northern goshawk optimization-long short-term memory) model applied to gas detection are designed to improve the accuracy of sensor. Among them, the design of the temperature compensation and spectral drift correction reduces the effect of temperature and other environmental factors. Theoriginal second harmonic signal was denoised using the CEEMDAN-WPD (complete ensemble empirical mode decomposition with adaptive noise-wavelet packet decomposition) algorithm. And the NGO-LSTM algorithm was appliedto NH3 concentration inversion, adaptively optimizing theweight parameters. The experiment reflects that the measured value of the sensor has an excellent linear relationship with the set value (R2 0.9992). The long-term stability of the sensor was verifiedbased on 400 ppb NH3, with an RMSE (root mean square error) of 4.754 ppb. Allan-Werle bias analysis shows that the detection limit (LoD) is approximately 792 ppt at an integration time of 232 s. Subsequent response time and atmospheric environment simulation experiments have proven that this sensor provides an efficient approach for real-time monitoring of NH3.

METROLOGICAL SUPPORT FOR THE INFORMATION-MEASUREMENT SYSTEM OF ELECTRIC ENERGY ACCOUNTING

The primary features of the government tools used to measure electric energy include the errors that arise during electricity accounting, which is essential for the development of the national economy within an information-sharing system. Issues related to reducing these errors and the associated losses are also addressed. The study analyzes the main characteristics of the measurement devices employed for electric energy accounting. It explores the causes and origins of errors in the measurement channel when developing an information-measurement system. Based on the analysis results, the sources of errors in measurement channels are identified according to the structural schemes of information-measurement systems utilizing various measuring devices (such as voltmeters, ammeters, electric energy meters, and voltage and current transformers). It has been demonstrated that errors in the measurement channel arise not only from the design and operating principles of the measuring instruments and signal processing devices but also due to distortions caused by harmonics in the voltage and current within the electrical network, as well as specific interferences. The primary sources of measurement errors in determining electric energy are mainly related to inaccuracies in measuring voltage, current, and phase shift, along with errors induced by temperature effects on the elements and devices used for these measurements. Although temperature errors may not be immediately apparent, they can contribute to various types of inaccuracies. In this context, the importance of implementing temperature compensation or correction schemes has been emphasized once again. Keywords: phase slip; electrical energy; information and measurement system; indirect measu¬rement; measurement error.