SENSORS

What is a Magneto Resistive Sensor (Magnetoresistive / Magneto-resistive)?

​

A Magneto Resistive Sensor is a non-contact sensor that uses changes in a magnetic field to detect position, movement, speed or angle. The sensor measures changes in the electrical resistance of a magnetically sensitive material, allowing precise and reliable measurement in industrial automation applications. Magnetoresistive sensors are commonly used in encoders, motors, pneumatic cylinders, positioning systems and rotational speed measurement.

​

In industrial automation, they are commonly used for position, speed, rotation, angle and proximity measurement, particularly where reliable non-contact sensing is required.​

​​

​​

How does a Magneto Resistive Sensor work?

​

A Magneto Resistive Sensor contains a material whose electrical resistance changes depending on the strength and/or direction of an applied magnetic field.

​

A magnet or magnetised target moves relative to the sensor. As the magnetic field changes, the sensor detects the corresponding resistance change and converts it into an electrical signal that can be interpreted by a PLC, controller, encoder or measurement system.​

​

Unlike an inductive sensor, the target does not necessarily need to be electrically conductive.

​​

​

Common industrial applications

​

Rotary encoders – measuring shaft position, rotational speed and direction.

​

Linear position sensing – determining the position or movement of machine components.

​

Cylinder sensors – detecting the position of a magnet inside pneumatic or hydraulic cylinders.​

​

Motor feedback – measuring rotor position and speed.

​

Gear and wheel detection – monitoring rotational movement and speed.

​

Angle measurement – detecting the angular position of shafts, valves and actuators.

​

Proximity and limit detection – determining whether a magnet or magnetised component has reached a particular position.

​

​

Magneto Resistive vs Hall-effect sensors

​

Both technologies detect magnetic fields, but magneto resistive sensors can offer higher sensitivity and greater positional accuracy than conventional Hall-effect sensors. This makes MR technology particularly attractive for precision encoders and position-measurement systems. 

​

There are several types of magneto resistive technology, including AMR (Anisotropic Magneto Resistance), GMR (Giant Magneto Resistance) and TMR (Tunnel Magneto Resistance). Each offers different levels of sensitivity, accuracy and power consumption.