Power Budget per Reading across Competing Sensing Principles
Sensing power budgets depend on physical excitation energy, analog settling delays, and converter sampling overhead across operating duty cycles.
IEPE Accelerometer
Piezoelectric Transducer
Vibration measurement instruments frequently combine a mechanical sensing element with an internal charge amplifier to simplify signal conditioning. An iepe accelerometer outputs a low impedance voltage signal over a standard coaxial cable, which reduces sensitivity to cable motion and electromagnetic noise. This design integrates the FET amplifier directly into the sensor housing.
Constant Current
Powering the device requires a DC current source typically ranging from 2 to 20 milliamps. The iepe accelerometer modulates the supply voltage to represent the acceleration magnitude, allowing the same two wires to carry both power and data. Signal conditioners at the data acquisition end strip the DC bias to recover the AC vibration signal.
Dynamic Range
Sensitivity is usually fixed at the factory and expressed in millivolts per g. Because the iepe accelerometer has a limited voltage swing determined by the supply, high g shocks can clip the output and cause data loss. Selecting a sensor requires matching the expected vibration levels to the available headroom.
Frequency response typically extends from below 1 hertz to over 10 kilohertz depending on the mass of the internal seismic element.
Thermal Sensitivity
High temperatures can damage the internal electronics long before the piezoelectric crystal reaches its Curie point. An iepe accelerometer is generally rated for environments below 120 degrees Celsius.