Applications

Key Points Product: ACM 1200 High Accuracy MEMS Accelerometer Features: Bias Stability: 100 mg for reliable zero-g offset Resolution: 0.3 mg for precise measurements Temperature Range: Factory calibrated from -40°C to +80°C Applications: Designed for inclination monitoring in hydraulic structures, civil engineering, and infrastructure Advantages: High precision (0.1° tilt accuracy), effective in dynamic environments, addresses key criteria like low noise, repeatability, and cross-axis sensitivity, enhancing long-term reliability and performance in tilt sensing systems. In the field of MEMS systems, capacitive accelerometers have become a cornerstone technology for inclination or tilt sensing. These devices, essential for various industrial and consumer applications, face significant challenges, especially in dynamic environments where vibration and shock are prevalent. Achieving high precision, such as 0.1° tilt accuracy, requires addressing a range of technical specifications and error factors. This article delves into the key criteria and solutions for effective tilt sensing using MEMS accelerometers. 1.Key Criteria for Accurate Tilt Sensing Bias Stability: Bias stability refers to the accelerometer’s ability to maintain a consistent zero-g offset over time. High bias stability ensures that the sensor readings remain reliable and do not drift, which is crucial for maintaining accuracy in tilt measurements.   Offset Over Temperature: Temperature variations can cause shifts in the accelerometer’s zero-g offset. Minimizing these shifts, known as tempco offset, is essential to maintain accuracy across different operating conditions. Low Noise: Noise in sensor readings can significantly affect the accuracy of tilt measurements. Low-noise accelerometers are vital for achieving precise and stable tilt readings, particularly in static environments. Repeatability: Repeatability refers to the sensor’s ability to produce the same output under identical conditions over multiple trials. High repeatability ensures consistent performance, which is critical for reliable tilt sensing. Vibration Rectification: In dynamic environments, vibration can distort tilt data. Effective vibration rectification minimizes the impact of these disturbances, allowing for accurate tilt measurements even when the sensor is subjected to external vibrations. Cross-Axis Sensitivity: This parameter measures how much the sensor output is affected by accelerations perpendicular to the measurement axis. Low cross-axis sensitivity is essential to ensure that the accelerometer responds accurately to tilt along the intended axis only. 2.Challenges in Dynamic Environments Dynamic environments pose significant challenges for MEMS accelerometers in tilt sensing applications. Vibration and shock can introduce errors that corrupt tilt data, leading to significant measurement inaccuracies. For instance, achieving <1° tilt accuracy is extremely challenging in such conditions, while attaining >1° accuracy is more feasible. Understanding the sensor’s performance and the application’s environmental conditions is crucial to optimizing tilt measurement accuracy. 3.Error Sources and Mitigation Strategies Several error sources can affect the accuracy of MEMS accelerometers in tilt sensing:   Zero-g Bias Accuracy and Shift: Zero-g bias errors can arise from soldering, PCB enclosure alignment, and temperature changes. Postassembly calibration can reduce these errors. Sensitivity Accuracy and Tempco: Variations in sensitivity due to temperature changes must be minimized to ensure accurate readings. Nonlinearity: Nonlinear responses can distort measurements and need to be corrected through calibration. Hysteresis and Long-Term Stability: Hysteresis and stability over the sensor’s lifetime can impact accuracy. These issues are often addressed through high-quality manufacturing and design practices. Humidity and PCB Bending: Environmental factors such as humidity and mechanical stresses from PCB bending can introduce additional errors. In-situ servicing and environmental controls are necessary to mitigate these effects. For example, the ACM 1200 High Accuracy MEMS Accelerometer is tailored specifically for inclination applications. It boasts the bias stability of 100 mg and resolution of 0.3 mg The factory calibration characterizes the entire sensor signal chain for sensitivity and bias over a specified temperature range (typically −40°C to +80°C), ensuring high precision and reliability upon installation. It is suitable for long-term installation in hydraulic structures such as concrete dams, panel dams, and earth-rock dams, as well as in civil and industrial buildings, roads, bridges, tunnels, roadbeds, and civil engineering foundations. It facilitates the measurement of inclination changes and enables the automated collection of measurement data. 4. Conclusion MEMS capacitive accelerometers are pivotal in achieving accurate tilt sensing, but they must overcome various challenges, especially in dynamic environments. Key criteria such as bias stability, offset over temperature, low noise, repeatability, vibration rectification, and cross-axis sensitivity play critical roles in ensuring precise measurements. Addressing error sources through calibration and employing integrated solutions like iSensors can significantly enhance the performance and reliability of tilt sensing systems. As technology advances, these sensors will continue to evolve, offering even greater accuracy and robustness for a wide range of applications.   ACM1200 High Performance Industry Current Type Mems Accelerometer Sensor Factory    

Key Points Product: Q-Flex Quartz Accelerometer Key Features: Components: High-purity quartz pendulum design with a closed-loop feedback system for precise acceleration measurements. Function: Provides accurate, stable acceleration data, with low noise and good long-term stability, especially effective in closed-loop operation. Applications: Ideal for aircraft navigation and attitude control, geological exploration, and industrial environments requiring precise inertial measurements. Measurement Method: Closed-loop frequency response measurement, ensuring reliable damping parameter estimation and accurate performance. Conclusion: The Q-Flex accelerometer offers high precision and stability, making it valuable for navigation, control, and industrial measurement applications. Q-Flex accelerometer is a kind of inertial measurement device, which utilizes the quartz pendulum to measure the acceleration of the object by the characteristic of deviating from the equilibrium position by the inertial force. Thanks to the low temperature coefficient of high-purity quartz material and stable structural characteristics, Q-Flex accelerometer has high measurement accuracy, low measurement noise, good long-term stability, and is widely used in attitude control, navigation and guidance of aircraft, as well as geological exploration and other industrial environments. 1.Detection method for Q-Flex Accelerometer When the system is open-loop, because the system can not produce feedback moment, the pendulum assembly is subjected to weak inertia moment or the active moment of the torque converter, the quartz pendulum easily touches the yoke iron and saturated phenomenon, which makes it very difficult to test the damping parameters under the open-loop, therefore, the damping parameters are considered to be measured under the closed-loop state of the system. The closed-loop frequency characteristics of the control system reflect the variation of the amplitude and phase of the output signal with the frequency of the input signal. The frequency response of the stabilized system is at the same frequency as the input signal, and its amplitude and phase are functions of the frequency, so the amplitude-phase characteristic curve of the frequency response can be applied to determine the mathematical model of the system. In order to obtain the actual damping parameters of the accelerometer, the closed-loop frequency response measurement method is used. In the closed-loop frequency response measurement method, the accelerometer is fixed on the horizontal vibration table in the “pendulum” state, so that the acceleration input direction of the vibration table is aligned with the sensitive axis of the accelerometer and the accelerometer is placed horizontally in the “pendulum” state, which can eliminate the asymmetry of the gravitational force on the input acceleration. The horizontal placement of the accelerometer in the “pendulum state” eliminates the effect of gravity on the asymmetry of the input acceleration. Fig.1 Close Loop amplitude Frequency characteristic curve of qfas By controlling the horizontal shaker, a sinusoidal acceleration signal of 6 g (g is the acceleration of gravity, 1 g ≈ 9.8 m/s2), with a gradually increasing frequency from 0 to 600 Hz, is applied to the Q-Flex accelerometer, which can reflect the amplitude attenuation and phase delay of the output of the accelerometer within the design range and bandwidth of the accelerometer. Accelerometer will produce the corresponding output under the action of the shaking table, the high sampling rate recorder connected to both sides of the sampling resistance, recording the output of the accelerometer, and plot the amplitude-frequency characteristic curve shown in Figure 1. In the passband of the accelerometer amplitude-frequency characteristic curve, the quartz flexural accelerometer maintains a good acceleration following ability, with the increase of the input acceleration frequency, the system resonance peak at 565Hz, the resonance peak is Mr=32dB, the cutoff frequency of the system is 582Hz, the amplitude of the system at the frequency began to produce more than 3dB of attenuation. Since the rotational inertia, stiffness and the rest of the parameters of the servo control loop of the Q-Flex accelerometer are known, the amplitude-frequency characteristics of the system are used to solve for the unknown parameter δ. The closed-loop transfer function of the system is given as Equation 1 The least-squares method estimates the parameters of the model based on the actual observed data, and a set of frequency amplitude data is obtained by generating an external acceleration input through a horizontal shaker, which is measured by a pen register, as shown in Table 1. Tab.1 Frequency Amplitudesamplingdataofqfas The amplitude-frequency response function of the quartz flexural accelerometer system with known parameters is the objective function, and the residual sum of squares with unknown parameters is established as Equation 2 Where, n is the number of selected feature points. Using the above equation, a suitable value of δ is selected so that D(δ) has the minimum value. The desired damping coefficient is obtained as δ=7.54×10-4N·m·s/rad using least squares fitting. The closed-loop simulation model of the system is established, and the damping coefficient is substituted into the quartz flexural accelerometer head model and the system is simulated, and the amplitude-frequency characteristic curve of the system is plotted as shown in Fig. 2, which is closer to the measured curve. Fig.2 Realityamplitude Frequency characteristic and parametrics imulation output Some studies have solved the damping distribution of the piezoelectric film on the surface of the pendulum by the finite time domain difference method, and the damping coefficient of the piezoelectric film of the pendulum is 1.69×10-4N·m·s/rad, which indicates that the damping coefficient obtained by the system amplitude-frequency response identification has the same order of magnitude as the theoretical calculated value, and the error originates from the damping of the material of the mechanical structure, the mounting error during installation and testing, the input error of the shaker, and other environmental factors. environmental factors. 2.Conclusion Micro-Magic Inc provides high-precision quartz accelerometers, such as AC-5, with small error and high precision, which have a bias stability of 5μg, scale factor repeatability of 50~100ppm, and a weight of 55g, and can be widely used in the fields of oil drilling, carrier microgravity measurement system, and inertial navigation.   AC5 Large Measurement Range 50g Quartz Pendulum Accelerometer Quartz Flex Accelerometer  

Key Points Product: Quartz Flexure Accelerometer Key Features: Components: Employs quartz flexure technology for high sensitivity and low noise in measuring acceleration. Function: Suitable for both static and dynamic acceleration measurements, with minimal impact from low-pressure environments. Applications: Ideal for monitoring micro-vibration in spacecraft orbits and applicable in inertial navigation systems. Performance Analysis: Demonstrates negligible scale factor changes (less than 0.1%) in vacuum conditions, ensuring accuracy and reliability. Conclusion: Offers robust performance for long-term on-orbit applications, making it suitable for high-precision aerospace requirements. The quartz flexure accelerometer has the characteristics of high sensitivity and low noise, making it suitable for measuring both static and dynamic acceleration. It can be used as an acceleration-sensitive sensor for monitoring micro-vibration environments in spacecraft orbits. This article mainly introduces effect of low pressure environment on quartz flexible accelerometer. The sensitive diaphragm of the quartz accelerometer experiences membrane damping effects when in motion in the air environment, which could potentially cause changes in the sensor’s performance (scale factor and noise) in low-pressure environments. This could affect the accuracy and precision of measuring on-orbit micro-vibration acceleration. Therefore, it is necessary to analyze this effect and provide a feasibility analysis conclusion for the long-term use of quartz flexible accelerometers in high vacuum environments. Fig.1 Quartz Accelerometers In Spacecraft Orbits 1.Damping analysis in low-pressure environments The longer the quartz flexure accelerometer operates in orbit, the more air leakage occurs inside the package, resulting in lower air pressure until it reaches equilibrium with the space vacuum environment. The average free path of air molecules will continuously lengthen, approaching or even exceeding 30μm, and the airflow state will gradually transition from viscous flow to viscous-molecular flow. When the pressure drops below 102Pa, it enters the molecular flow state. The air damping becomes smaller and smaller, and in the molecular flow state, the air damping is almost zero, leaving only electromagnetic damping for the quartz flexible accelerometer diaphragm. For quartz flexure accelerometers that need to operate for a long time in low-pressure or vacuum environments in space, if there is significant gas leakage within the required mission life, the membrane damping coefficient will significantly decrease. This will change the characteristics of the accelerometer, making scattered free vibrations ineffective in attenuation. Consequently, the scale factor and noise level of the sensor may change, potentially affecting measurement accuracy and precision. Therefore, it is necessary to conduct feasibility tests on the performance of quartz flexible accelerometers in low-pressure environments, and compare the test results to assess the extent of the impact of low-pressure environments on the measurement accuracy of quartz flexible accelerometers. 2.Impact of low-pressure environments on the scale factor of quartz flexure accelerometers Based on the analysis of the working principles and application environments of quartz flexible accelerometer products, it is known that the product is encapsulated with 1 atmosphere pressure, and the application environment is a low Earth orbit vacuum environment (vacuum degree approximately 10-5 to 10-6Pa) at a distance of 500km from the ground. Quartz flexible accelerometers typically use epoxy resin sealing technology, with a leakage rate generally guaranteed to be 1.0×10-4Pa·L/s. In a vacuum environment, the internal air will slowly leak out, with the pressure dropping to 0.1 atmosphere pressure (viscous-molecular flow) after 30 days, and dropping to 10-5Pa (molecular flow) after 330 days. The impact of air damping on quartz flexure accelerometers mainly manifests in two aspects: the impact on the scale factor and the impact on noise. According to design analysis, the impact of air damping on the scale factor is approximately 0.0004 (when the pressure drops to vacuum, there is no air damping). The calculation and analysis process is as follows: The quartz flexure accelerometer uses the gravity tilt method for static calibration. In the accelerometer’s pendulum assembly, in an environment with air, the normal force on the pendulum assembly is: mg0, and the buoyant force fb is: ρVg0. The electromagnetic force on the pendulum is equal to the difference between the force it experiences due to gravity and the buoyant force, expressed as: f=mg0-ρVg0 Where: m is the mass of the pendulum, m=8.12×10−4 kg. ρ is the density of dry air, ρ=1.293 kg/m³. V is the volume of the moving part of the pendulum assembly, V=280 mm³. g0 is the gravitational acceleration, g0=9.80665 m/s². The percentage of the buoyant force to the gravitational force on the pendulum assembly itself is: ρVg0/mg0=ρV/m≈0.044% In a vacuum environment, when the air density is approximately zero due to gas leakage causing the pressure inside and outside the instrument to balance, the change in scale factor of the quartz flexible accelerometer is 0.044%. 3.Conclusion: Low-pressure environments can affect the scale factor and noise of the quartz flexible accelerometer. Through calculation and analysis, it’s shown that the maximum impact of the vacuum environment on the scale factor is not more than 0.044%. Theoretical analysis indicates that the influence of low-pressure environments on the sensor’s scale factor is less than 0.1%, with minimal impact on measurement accuracy, which can be neglected. This demonstrates that low-pressure or vacuum environments have minimal effects on the scale factor and noise of the quartz flexure accelerometer, making it suitable for long-term on-orbit applications. It’s worth noting that the AC7 series quartz flexible accelerometers are designed specifically for aerospace applications. Among them, the AC7 has the highest precision, with zero bias repeatability ≤20μg, a scale factor of 1.2mA/g, and scale factor repeatability ≤20μg. It is fully suitable for monitoring micro-vibration environments of spacecraft in orbit. Additionally, it can be applied to inertial navigation systems and static angle measurement systems with high precision requirements.   AC-5 Low Deviation Error Accelerometer Quartz Vibration Sensor for Imu Ins    

Key Points Product: High Temperature Accelerometers Key Features: Components: Designed with advanced materials and technologies, such as amorphous quartz structures for enhanced stability. Function: Provide reliable and accurate data in extreme environments, crucial for safety and performance. Applications: Essential in oil & gas (MWD systems), aerospace (structural monitoring), automotive testing (crash and performance assessments), and various industrial sectors. Data Integrity: Capable of operating under high temperatures and vibrations, ensuring continuous performance and minimal downtime. Conclusion: High temperature accelerometers are vital for industries operating in harsh conditions, enhancing efficiency and safety with precise measurements. Reliability is crucial for success in the challenging oil and gas industry, where risks are frequent and can significantly impact opportunities. Dependable, precise data can determine whether a venture succeeds or fails. Ericco has been supplying robust sensing products to the global oil and gas sector, proving their exceptional reliability and accuracy in some of the world’s most demanding environments. 1.What are high temperature accelerometers? High temperature accelerometers are designed to withstand harsh conditions and provide accurate data in demanding industries such as aerospace and oil & gas. Essentially, their purpose is to function effectively in challenging environments, including underground settings and extreme temperatures. Manufacturers of high temperature accelerometers employ specific technologies to ensure the sensors’ reliability in extreme conditions. For instance, Micro-Magic Incs Quartz Accelerometer for Oil and Gas is proved to own high performance. This model utilizes an amorphous quartz proof-mass structure that reacts to acceleration through flexure motion, ensuring excellent stability in bias, scale factor, and axis alignment. 2.How are high temperature accelerometers used? High temperature accelerometers are vital in industries where equipment must endure extreme conditions. Their robust design and advanced technology enable them to operate reliably in harsh environments, providing crucial data that enhances safety, efficiency, and performance. Here’s a closer look at their applications and significance: 2.1 Oil & Gas Industry In the oil & gas industry, high temperature accelerometers are essential components of Measurement While Drilling (MWD) systems. MWD is a well logging technique that uses sensors within the drillstring to provide real-time data, guiding the drill and optimizing drilling operations. These accelerometers can withstand the intense heat, shock, and vibrations encountered deep underground. By delivering accurate measurements, they help. Optimize Drilling Operations: Provide precise data on the drill bit’s orientation and position, aiding in efficient and accurate drilling. Enhance Safety: Detect vibrations and shocks that could indicate potential issues, allowing for timely intervention and prevention of accidents. Improve Efficiency: Reduce downtime by providing continuous, reliable data that helps prevent operational failures and costly interruptions. Fig.1 High Temperature Accelerometers 2.2 Aerospace In the aerospace industry, high temperature accelerometers are used to monitor the performance and structural integrity of aircraft. They can endure the extreme conditions of flight, including high temperatures and intense vibrations, and are crucial for Structural Health Monitoring: Measure vibrations and stresses on aircraft components, ensuring they remain within safe limits. Engine Performance: Monitor vibrations in aircraft engines to detect anomalies and prevent engine failures. Flight Testing: Provide accurate data on aircraft dynamics during test flights, aiding in the development and refinement of aircraft designs. 2.3 Automotive Testing In automotive testing, high temperature accelerometers are employed to measure vehicle dynamics and structural integrity under extreme conditions. They are particularly useful for: Crash Testing: Monitor acceleration and deceleration forces during crash tests to evaluate vehicle safety and crashworthiness.High-Performance Testing: Measure vibrations and stresses in high-performance vehicles to ensure components can withstand extreme driving conditions.Durability Testing: Assess the long-term durability of automotive components by subjecting them to prolonged high temperatures and vibrations. 2.4 Industrial Applications Beyond oil & gas, aerospace, and automotive industries, high temperature accelerometers are also used in various other industrial applications where equipment operates in extreme conditions. These include: Power Generation: Monitor vibrations in turbines and other equipment to ensure optimal performance and prevent failures.Manufacturing: Measure vibrations and stresses in heavy machinery to maintain operational efficiency and safety.Robotics: Provide precise data on the movements and stresses experienced by robots operating in high-temperature environments, such as those used in welding or foundries. 3.Micro-Magic Inc's High Temperature Accelerometers Micro-Magic Inc has excelled in designing and manufacturing high-temperature accelerometers that meet the demanding requirements of these industries. We offer solutions tailored for energy exploration and other high-temperature applications. These accelerometers feature: Analog Output: For easy integration with existing systems.Mounting Options: Square or round flanges to suit different installation needs.Field-Adjustable Range: Allowing customization to specific application requirements.Internal Temperature Sensors: For thermal compensation, ensuring accurate measurements despite temperature variations. What’s more, Micro-Magic Inc’s Quartz Accelerometer for Oil and Gas is proved to own high performance. This model utilizes an amorphous quartz proof-mass structure that reacts to acceleration through flexure motion, ensuring excellent stability in bias, scale factor, and axis alignment. Some high temperature accelerometers also incorporate external amplifiers to safeguard the sensor from heat damage. And we recommend the AC1 for oil and gas, whose operating temperature is -55 ~ +85 ℃, with an input range of ±50g, bias repeatability <30μg, and scale factor repeatability <50 ppm. 4.Conclusion High temperature accelerometers are indispensable in industries that operate under extreme conditions. Their ability to provide reliable and accurate data in such environments enhances operational efficiency, safety, and performance. With advancements in technology, these sensors continue to evolve, offering even greater reliability and precision in the most demanding applications. AC1 Navigation Class Level Quartz Flexible Accelerometer With Measurement Range 50G Excellent Long-Term Stability And Repeatability   AC2 50 G Quartz Flexure Accelerometer Quartz Pendulous Accelerometers Inertial Navigation  

Key Points Product: Quartz Flexible Accelerometer Key Features: Components: Uses high-precision quartz flexible accelerometers for accurate acceleration and tilt measurements. Function: Vibration analysis helps identify sensor error coefficients, improving measurement accuracy and performance. Applications: Widely used in structural health monitoring, aerospace navigation, automotive testing, and industrial machinery diagnostics. Data Analysis: Combines vibration data with signal processing algorithms to optimize sensor models and enhance performance. Conclusion: Delivers precise and reliable acceleration measurements, with strong potential in various high-precision industries. 1.Introduction: In the realm of sensor technology, accelerometers play a pivotal role in various industries, from automotive to aerospace, healthcare to consumer electronics. Their ability to measure acceleration and tilt across multiple axes makes them indispensable for applications ranging from vibration monitoring to inertial navigation. Among the diverse types of accelerometers, quartz flexible accelerometers stand out for their precision and versatility. In this article, we delve into the intricacies of identifying quartz flexible accelerometers through vibration analysis, exploring their design, working principles, and the significance of vibration analysis in optimizing their performance. 2.Importance of Vibration Analysis: For the accelerometer to be identified, first, conduct multi-directional vibration table tests on it. Obtain rich raw data through data acquisition software. Then, based on the test data, on the one hand, combine the overall least squares algorithm to identify its high-order error coefficients, improve its signal model equation, enhance the measurement accuracy of the sensor, and explore the relationship between the high-order error coefficients of the accelerometer and its operating status. Seek methods to identify its operating status through the high-order error coefficients of the accelerometer. On the other hand, extract its effective feature set, train neural networks, and finally modularize the effective data analysis algorithm through virtual instrument technology. Develop application software for identifying the operating status of quartz flexible accelerometers to achieve rapid and accurate identification of sensor operating status. This will help personnel to promptly improve internal circuit structures, enhance the measurement accuracy of accelerometers, and improve the yield of manufactured products during the processing and manufacturing process. Vibration analysis serves as a cornerstone in the characterization and optimization of quartz flexible accelerometers. By subjecting these sensors to controlled vibrations across different frequencies and amplitudes, engineers can evaluate their dynamic response characteristics, including sensitivity, linearity, and frequency range. Vibration analysis helps identify potential sources of error or non-linearity in accelerometer output, enabling manufacturers to fine-tune sensor parameters for enhanced performance and accuracy. 3.Identification Process: The identification of quartz flexible accelerometers through vibration analysis involves a systematic approach encompassing experimental testing, data analysis, and validation. Engineers typically conduct vibration tests using calibrated shakers or vibration excitation systems, exposing the accelerometers to sinusoidal or random vibrations while recording their output signals. Advanced signal processing techniques such as Fourier analysis and spectral density estimation are employed to analyze the frequency response of the accelerometers and identify resonance frequencies, damping ratios, and other critical parameters. Through iterative testing and analysis, engineers refine the accelerometer model and validate its performance against specified criteria. 4.Applications and Future Prospects: Quartz flexible accelerometers find applications across a diverse array of industries, including structural health monitoring, aerospace navigation, automotive testing, and industrial machinery diagnostics. Their high precision, robustness, and versatility make them indispensable tools for engineers and researchers striving to understand and mitigate the effects of dynamic forces and vibrations. Looking ahead, ongoing advancements in sensor technology and signal processing algorithms are poised to further enhance the performance and capabilities of quartz flexible accelerometers, unlocking new frontiers in vibration analysis and dynamic motion sensing. In conclusion, the identification of quartz flexible accelerometers through vibration analysis represents a critical endeavor in sensor technology, enabling engineers to unlock the full potential of these precision instruments. By understanding the working principles, conducting thorough vibration analysis, and refining sensor performance, manufacturers and researchers can harness the capabilities of quartz accelerometers for a myriad of applications, ranging from structural monitoring to advanced navigation systems. As technological innovation continues to accelerate, the role of vibration analysis in optimizing sensor performance will remain paramount, driving advancements in precision measurement and dynamic motion sensing. 5.Conclusion Micro-Magic Inc provides high-precision quartz flexible accelerometers, such as AC1, with small error and high precision, which have a bias stability of 5μg, scale factor repeatability of 15~50 ppm, and a weight of 80g, and can be widely used in the fields of oil drilling, carrier microgravity measurement system, and inertial navigation.   AC1 Navigation Class Level Quartz Flexible Accelerometer With Measurement Range 50G Excellent Long-Term Stability And Repeatability