since 2002
The active element of an accelerometer is a piezoelectric material. Figure 1 illustrates the piezoelectric effect with the help of a compression disk. A compression disk looks like a capacitor with the piezoceramic material sandwiched between two electrodes. A force applied perpendicular to the disk causes a charge production and a voltage at the electrodes.
Under normal conditions, piezoelectric sensors are extremely stable and their calibrated performance characteristics do not change over time. However, often sensors are exposed to harsh environmental conditions, like mechanical shock, temperature changes, humidity etc. Therefore it is recommended to establish a recalibration cycle. For applications where high accuracy is required, we recommend to recalibrate the accelerometer every time after use under severe conditions or at least every 2 years. In some less critical applications, for example in machine monitoring, recalibration may be unnecessary.