International Standard
Primary measurement standards establish the accuracy of vibration transducers through laser interferometry or comparison methods. The iso 16063 vibration calibration standard defines the methods and instrumentation requirements for verifying accelerometer sensitivity across different frequencies. This standard ensures that acceleration measurements taken across different labs are traceable to the same global reference.
Traceability Chain
Calibration procedures require either primary methods using laser interferometry to measure displacement or secondary comparison methods using a reference transducer. In primary calibration, the system measures the Doppler shift of a laser beam reflected from the vibrating surface to determine absolute acceleration with high accuracy. The comparison method mounts the test sensor back to back with a calibrated reference sensor on a common shaker table, allowing direct voltage output comparison.
Uncertainty Budget
Compiling the uncertainty budget includes factors like transverse motion of the shaker, mounting torque variations, and environmental noise. These noise sources are controlled to keep measurement uncertainty below specified margins. Lab accreditation requires regular participation in round robin tests to prove compliance.
Excitation Condition
Frequency sweeps run from low sub hertz ranges up to several tens of kilohertz depending on the sensor class. High frequency verification requires careful attention to the mounting surface finish to prevent mechanical resonances from distorting the sensitivity curve. The resulting calibration curve lists the sensitivity value and phase shift for each test frequency.
