Why Magnetic Encoders?

The Traditional Solution

For many years, optical encoders have been the traditional choice for motion control. Optical encoders use line-of-sight sensing to create signals. It works when a light source splits into two 90-degree out-of-phase beams that pass through transparent, evenly spaced windows in a rotating optical disk.

The light is then read by the receiver and converted into digital square wave quadrature output signals. With a clear, consistent and transparent line of sight, optical encoders are accurate, reliable and affordable sensors in clean, quiet environments.

The Need for a New Solution

As automation evolves to encompass more industries such as paper handling, power generation or other environments that are high-heat, high-humidity or subject to shock or vibration, continuous accuracy with optical encoders is difficult to achieve.

Line of sight becomes compromised with dirt, dust and other contaminates, and fluctuating heat and humidity can form condensation on the rotating disc. Additionally, maintaining a correct air gap with an optical encoder (typically less than 0.25 mm, or 0.010”) is not always possible in high shock or vibration climates.

Many optical encoder manufacturers have devised solutions to make optical encoders able to perform in tough environments, but the result is often a bulkier, higher priced product.

A Superior Sensing Solution

New advancements in magnetic encoding technology have resulted in the development of compact, low-cost encoders that are more tolerant of harsh, dirty operating environments. Timken engineers have patented magnetic encoder designs that use Hall effect technology to obtain high resolution from a durable magnetic target disc.

Magnetic sensing does not need a clean, transparent gap, are inherently heat, humidity, shock and vibration resistant and are compact and rugged by nature. Plus, they can be integrated into existing systems, or customized to fit new designs.

Compare optical encoders and magnetic encoders side by side:

Optical Encoders

Magnetic Encoders
  • Requires clear, transparent line of sight
  • Line of sight can be filled with dirt, dust or non-ferrous contaminants
  • Must maintain correct air gap of less than .25mm
  • Accurate with gaps up to 4mm
  • Susceptible to condensation on the rotating disc in fluctuating heat and humidity
  • Heat and humidity resistant
  • Compromised accuracy in vibration or shock environments
  • Shock and vibration resistant
  • Requires bulky, sealed casing to function well in difficult environments, which adds to cost
  • Compact, low-cost and rugged, without a bulky outer shell
  • Moving parts
  • No moving parts
  • Difficult to adapt to existing configurations
  • Can be customized as a replacement part or customized to fit new designs

Magnetic sensors from Timken are the superior sensing solution that enhances products and handles most jobs in a quickly evolving industrial landscape.

Browse our magnetic encoders, or contact us with questions.