Accurate Robust Measurements
Frequently playing critical roles in automotive and industrial equipment, sensing technologies must be highly accurate, reliable and robust. Magnetoresistive (MR) sensors fulfil all these requirements and bring a whole range of benefits too. For example they perform their measurement duties without needing to touch the parts they are measuring. This means wear-free operation that doesn’t affect the measurement process.
Common-sense sensors for exceptional systems
Our sensors are based on the MR effect, in which a magnetic field can affect a material’s electrical resistance. In MR sensors, the electrical resistance of a current-carrying magnetic material, such as a permalloy (19% Fe, 81% Ni) is altered by an external magnetic field. By applying the field in the plane of the current flow, the material’s own internal magnetization vector rotates according to the angle of the field, changing its electrical resistance.
A subsequent integrated circuit transforms the analogue into a digital output signal. The output level is independent of the sensing distance within the measurement range
The MR effect
The exceptional accuracy, reliability and robustness of MR sensors make them ideal for automotive applications. Applications can employ a wide air gap between sensor and target. This is possible due to conditioning the MR sensor’s signal, where the offset, gain and hysteresis are digitally adapted to ensure an exceptional air gap capability.
Round and Round We Go
Accurate rotational speed measurement is a vital component in maintaining performance, safety and reliability in modern vehicles. It forms the basis of numerous applications from anti-lock braking to engine management systems, and opens the way for embedding intelligence throughout the car with the introduction of advanced in-vehicle networks and control systems.
When sensing the motion of ferrous gear wheels or magnetized targets, MR sensors change the cyclically fluctuating flux into an analog electrical signal. The signal’s frequency is proportional to the rotational speed.
Using MR sensor technology gives designers a true angular measurement system which is independent of magnetic field strength variations and insensitive to airgap and eccentricity variations.
Highly accurate, NXP’s angle sensors are ideal for a variety of demanding automotive and industrial applications. These easy-to-use devices provide an output signal virtually independent of magnet tolerances, magnet temperature coefficients, magnet-sensor distance and positioning tolerances, guaranteeing reliability and simplifying your manufacturing process.
MR Sensing Enables
- Contactless angle measurement up to 180°
- Measurement independent of magnetic drift caused by life time and temperature changes
- Operation independent of mechanical tolerances and magnet shifts caused by thermal stress
- Highly flexible solutions that measure any automotive angle effectively