How do magnetic sensors work with multi-track scales?

Sensors are everywhere. They make our tech work better and smarter. BOGEN Magnetics knows this well.

Incremental and absolute magnetic sensors work by detecting changes in magnetic fields. They use magnetic scales, like tapes or rings, to do this.

 

Incremental sensors

Incremental magnetic sensors detect relative changes in position by reading regularly spaced magnetic poles on a scale.

They use the Hall effect or magnetoresistive elements to sense changes in the magnetic field. As the sensor moves, it generates square wave signals. These signals, usually in A and B channels, are offset by 90 degrees. This helps in determining the direction and increasing resolution. An external controller counts these pulses to find the relative position and speed.

 

Absolute sensors

Absolute magnetic sensors on the other hand, provide unique position information at any point along the scale. They read multiple tracks on the scale, each with a different pattern. The sensor interprets these patterns to determine an absolute position. The sensor then outputs the position directly, often using digital interfaces like SSI, BiSS, or SPI.

 

BOGEN Magnetics offers both types of sensors 

BOGEN's sensors can achieve high resolutions, with some models offering up to 18-bit absolute position output. They support multiple output interfaces, including incremental (ABI), analog (sin/cos), and various digital absolute protocols. Our absolute sensors use radial Hall sensing of a 2 or 3-track magnetic wheel. This employs the nonius principle for high accuracy. Differential sensing is another technique used in their sensors, effectively reducing the influence of external magnetic interference.

 

Customization is a key feature of BOGEN products

BOGEN offers sensors tailored for specific applications, with options for different resolutions, interfaces, and environmental tolerances. The performance of these magnetic sensors is closely tied to the quality and precision of the magnetic scale. BOGEN provides high-quality scales made from elastomer-bonded ferrite or hard ferrite, ensuring optimal system performance.

Custom designs are available in both linear (tape) scales and rotary (ring) scales to suit different types of motion control and measurement applications. We can produce scales with single or multiple tracks, allowing for both incremental and absolute position measurements. Customization options include adding reference marks, varying accuracy classes, and other features to meet particular industrial needs.

 

Multi-track design of magnetic tapes and rings

BOGEN Magnetics also offers magnetic scales with multi-track designs, including three-track configurations for both tapes and rings. This design allows for more complex encoding schemes, enabling both incremental and absolute position measurements in a single scale. One track can be dedicated to absolute position encoding, while the other two tracks provide incremental data, allowing for high-resolution absolute positioning. Multiple tracks can be used for error checking and correction, improving overall measurement accuracy.

Our three-track scales are versatile and can be used in various industries, including industrial automation, robotics, and precision manufacturing equipment. These scales are compatible with BOGEN's advanced magnetic sensors, capable of reading multiple tracks simultaneously. They are available in both linear (tape) and rotary (ring) formats, providing solutions for different types of motion control and measurement applications. Durability is also a key feature, designed for long-term reliability in industrial environments.

The production of multi-track magnetic scales demonstrates our expertise in creating sophisticated magnetic measurement solutions. Our scales are adaptable to a wide range of industrial measurement and control tasks.

 

Magnetics For Kids

You can download our short presentation on how the sensor works, which is suitable even for children as young as 6 years old.