Electro Electric Corporation

Absolute Encoders

 

Each absolute encoder is used to determine the speed or position of something – the difference is in how that encoder determines that movement. The “how” defines what type of encoder works in your application.

 

Absolute encoders work in situations where accuracy for both speed and position, fail tolerance, and interoperability matters more than system simplicity.

 

An absolute rotary encoder determines its position using a static reference point. The method is slightly different depending on whether the absolute rotary encoder is optical or magnetic, but the principle is the same either way. There are two discs, both with concentric rings with offset markers. One disc is fixed to the central shaft; the other moves freely. As the disc turns, the markers along the track of absolute encoders change position on the fixed disc. Each configuration along the disc of an absolute rotary encoder represents a unique binary code. Looking at the binary code within the absolute rotary encoder determines the absolute position of the object. For optical absolute encoders, the marker is an opening which lets through light. For magnetic absolute encoders, the markers are a magnetic sensor array that passes over a magnet and detects the position of the magnetic poles.

 

By having an integrated reference, an absolute rotary encoder is intrinsically able to deliver higher quality feedback:

 

• Higher overall resolution and orientation

• Better start up performance because of low homing (or initial position) time

• Accurate motion detection along multiple axes

• Multiple output protocols for better electronics integration

• Better recovery from system or power failures

 

Another key feature of absolute encoders is the different output options. Encoders can’t just collect feedback data; they have to send it somewhere in a language that the larger system can understand. Absolute encoders use binary coding, which is translatable into many different protocols. If you have multiple components using the same communications bus (such as multiple electronics systems on a fire truck), then it is critical that the absolute rotary encoder can communicate with the bus.

 

Applications of Incremental Encoder:

 

Absolute encoders allow more precision work from applications:

 

• Determining multi-axis orientation for CNC machines used in parts manufacturing

• Automatically determining the height of scissor beds used in hospitals

• Accurately positioning multiple stabilizers for large vehicles like cranes or aerial lifts

• Moving automatic doors or bays without a limiting switch

• Continuing robotic movement cleanly even after a power failure

 

Our absolute encoder portfolio includes world class brands like:

 

• Balluf

• Baumer / Hubner

• BEI

• Dynapar

• Eltra

• Heidenhain

• Hensgstler

• Jayashree Encoders

• Koyo

• Kuebler

• Leine & Linde

• North Star

• Pepperl+Fuchs (P&F)

• Sick

• Tamagawa