The accuracy grade of a force sensor is mainly expressed through the comprehensive error (%FS) or the Class C standard for weighing sensors. Different grades correspond to different measurement accuracies and application scenarios.
1. Accuracy Grades Expressed as %FS (Full Scale Percentage)
This is the most common way to express the accuracy of force sensors, referring to the percentage of the maximum allowable error within the full scale range. Common grades are as follows:
0.03%FS: Ultra-high accuracy, suitable for scientific research and high-precision calibration equipment, such as the Rielt T521 series six-dimensional force sensor.
0.05%FS ~ 0.1%FS: High accuracy, used in industrial automation, robot force control, and precision testing equipment.
0.2%FS: Mid-to-high-end accuracy, widely used in automotive testing, aerospace, medical equipment, and other fields.
0.5%FS and above: Ordinary industrial-grade accuracy, suitable for cost-sensitive general weighing or force monitoring scenarios.
For example: A sensor with a range of 100kN and an accuracy of 0.03%FS has a maximum permissible error of 0.03kN (30N). This error will not exceed this value, regardless of whether the measured value is 10kN or 100kN.
2. Classification by Weighing Sensor Grade C Standard
This standard originates from the national standard GB/T 7551-2008 and is mainly used for weighing sensors. Higher grades have more divisions and higher accuracy:
C1 Grade: ≤0.1% error, suitable for high-precision laboratories and scientific research.
C3 Grade: ≈0.033%FS (1/3000 division), the most common high-precision grade in industry, widely used in electronic scales, weighbridges, automatic packaging machines, etc.
C6 to C30 Grades: Accuracy decreases sequentially, suitable for weighing large quantities of materials or dynamic weighing scenarios where high accuracy is not required.
Key Factors Affecting Accuracy
Nonlinearity, Repeatability, and Hysteresis: These three indicators collectively determine overall accuracy. High-quality sensors typically control this to within 0.03%FS.
Temperature Drift: Changes in ambient temperature can cause zero-point and sensitivity shifts. High-end products incorporate temperature compensation circuits.
Installation Method and Load Alignment: Off-center loading or lateral forces can affect measurement results; installation must strictly adhere to specifications.