RPM and velocity sensors A distinction is made between absolute rotating velocity in space and relative rotating velocity between two parts An example of absolute rotating velocity is the vehicle's yaw rate about its vertical axis Cyaw velocity), this is required for vehicle-dynamics control Examples of relative rotating velocity are the crankshaft and camshaft speeds, the wheel speeds(for ABS/TCS) and the speed of the diesel injection pump Measurements are mainly taken with the aid of an incremental sensor system comprising a gear and an min-1 sensor Newer applications Bearing-integrated min-1 sensors (wheel bearings. Simmer shaft-seal module on the crankshaft). Linear velocity. Vehicle yaw rate about the longitudinal axis (roll velocity for rollover protection)