Industrial vibration systems often report acceleration, velocity and displacement because each quantity emphasises a different part of machine behaviour. Choosing only one can conceal a developing fault outside its most sensitive frequency region.
Acceleration
Acceleration describes how rapidly velocity changes. It is particularly responsive to impacts, bearing-related activity, gear-tooth interaction and other higher-frequency phenomena. Peak acceleration and envelope-related indicators can reveal impulsive events that may be less obvious in an overall velocity value.
Velocity
Velocity represents the rate of motion and is widely used for overall machine-severity assessment. RMS velocity is useful for trending broad mechanical energy associated with unbalance, misalignment, looseness and structural response.
Displacement
Displacement describes the physical movement between extremes. It is most informative at lower frequencies, where shaft motion, slow-speed movement or large-amplitude structural behaviour may dominate.
Using all three together
- Trend equivalent operating states rather than mixing loaded, unloaded, accelerating and stopping conditions.
- Review all three axes because machine stiffness and fault orientation distribute energy unevenly.
- Use overall values for screening and harmonic or spectral indicators for diagnosis.
- Confirm the unit, scaling, peak convention and frequency filtering before comparing data from different systems.
Technical basis: PyXis Smart 3-Axis Vibration Sensor datasheet TTN-DS-2026-002, issued 19 July 2026. Confirm the current hardware, firmware and controlled document revision before implementation.
