Optical Rotary Encoders

Encoders are sensors that generate digital signals in response to movement. Encoders come with two outlines: rotary and linear. Both types sense mechanical motion and translate the information (velocity, position, acceleration) into useful data. 

A contactless technology 

To address demands for longer service life and with its strong track record in contact technology position sensors (potentiometers), Electromechanical Solutions SBU has been developing own-brand contactless sensors for nearly 10 years. These sensors are absolute and incremental optical encoders, magnetic technology and inductive sensors. 

Absolute optical or magnetic encoders: absolute optical encoders are position sensors that use optical signals to identify an absolute angular position. The Exxelia encoders offer very high performance levels for a very small footprint: 

• high precision (<30 arcsec), 
• high resolution (up to 21 bits), 
• highly thin (10mm), 
• EMI EMC compatibility 

Incremental optical or magnetic encoders: absolute optical encoders are position sensors that use optical signals to identify an absolute angular position. Incremental encoders have to be initialized by a first turn to produce an absolute position. 

Applications: Aeronautics, Defense, Railway, Medical, Oil exploration, Telecommunications 

Exxelia encoders can also be easily combined with other functions like Slip rings or rotary joints (FORJ, HF...) in complete proprietary systems.

A well-known image is that the difference between incremental and absolute encoders is similar to the difference between a stop watch and a clock. A stop watch measures the incremental time that elapses between its start and stop, just like an incremental encoder will provide a known number of pulses relative to a movement. If you knew the actual time when you started the watch, you can tell what time it is later by adding the elapsed time value from the stop watch. For position control, adding incremental pulses to a known starting position will measure the current position. When an absolute encoder is used, the actual position will constantly be transmitted, just as a clock will tell you the current time.

Exxelia is certified EN 9100, a quality standard specific to the aerospace, space, and defense sectors. Our facilities are also ISO 9001 certified (quality management), and some are certified ISO 13485 for medical devices. Other industry-specific standards, such as NADCAP or AQAP, may also apply depending on the products and markets.

The EN 9100 standard ensures a rigorous quality management system tailored to the critical requirements of the aerospace, space, and defense industries. It is required by major OEMs such as Airbus, Safran, Thales, or CNES. This certification guarantees product traceability, risk management, and compliance with international standards.

Yes, some of our facilities are ISO 13485 certified, the quality standard for medical devices. This certification enables Exxelia to design and manufacture components (such as coils, sensors, or capacitors) used in high-reliability medical equipment, including MRI scanners, ventilators, and imaging systems.

The railway industry demands durability, reliability, and long service life. While a dedicated certification like EN 9100 is not required, Exxelia applies IRIS standards and complies with IEC/EN regulations specific to railway applications. Our quality processes ensure component compliance for trains, metros, and tramways, including fire safety and electromagnetic compatibility.

Yes. Exxelia meets defense industry requirements through its EN 9100 certification and compliance with military standards (MIL-STD, STANAG). Our components are qualified for critical applications such as RF systems, embedded electronics, guided munitions, or radar systems. Some products are also subject to customer-specific qualification procedures.