Improving the Linear Ratio Inspection Standard for Seismic Acceleration Sensor Output Voltages

Abstract

In this study, the seismic acceleration sensor inspection standard, which estimates the error rate of the sensor’s output voltage to test its linear ratio, was analyzed and an improved standard was proposed. Seismic acceleration sensors should be sensitive to small angular changes under seismic excitation; however, the existing inspection standard only calculates the error rates at 30°, 45°, 60°, and 90° angles. Thus, we proposed an improved inspection standard that measures error ratios in 5° increments from 0° to 90°. Since the linear ratio is determined by estimating the error rate between theoretical and measured output voltages, the error rates in the X, Y, and Z directions were analyzed at changing angles. The results indicate that the error rate increased at small installation angles, and that the error rate decreased gradually at smaller angular increments. The current inspection standard underestimated the actual error rate, as it represented only 40~50% of the average error rate measured by the 5° interval measurements. Therefore, the current inspection standard for estimating the linear ratios of seismic acceleration sensors should be improved to reflect the influence of variations in the error rate according to the angular increment.