Optical Encoders

Quantic BEI optical encoders are available in a variety of configurations and sizes to meet the demands of any customer in any environment. Our offerings encompass housed, or un-housed (kit), absolute or incremental, and single-turn or multi-turn sensors for any motion control application. Quantic BEI provides the highest performance rotary sensing solutions for space, military, scientific, and commercial programs.

Absolute Kit Encoders

These absolute optical encoders are considered “kits” because they are delivered as major subcomponents (code disk & reading electronics), giving the user the ability to install at their own facility. Directly mounting the code disk to the host spindle decreases size and mass impact by eliminating the encoder’s bearing assembly and housing. Furthermore, this architecture removes the need for flexible couplings that can decrease the accuracy & precision of the rotary system. All Quantic BEI absolute encoders are considered True Absolute, meaning that no motion is required to determine angle after power up.

nanoSeries ARA

nanoSeries® ARA

ARA is Quantic BEI’s flagship space-qualified optical encoder in the nanoSeries® product line. This encoder has been designed to meet the performance and environmental requirements for the most demanding space missions. A system consists of a remote electronics box and up to four readheads. ARA transmits a 28-bit rotary position with the ability to self-calibrate over full and partial revolutions

Datasheet CAD Models
nanoSeries AIME-II

nanoSeries® AIME-II

AIME-II is Quantic BEI’s second implementation of the Absolute Intuitive Modular Encoder. This encoder is suited for terrestrial & airborne sensing applications that require high pointing performance in a modular package. AIME-II is performance and interface matched to the ARA system, but with all electronics contained in the readhead. AIME-II transmits a 28 bit rotary position with the ability to self-calibrate over full and partial revolutions.

Datasheet CAD Models
nanoSeries TRACKER

nanoSeries® TRACKER

TRACKER is a modular encoder system that offers high pointing performance at a lower cost than the ARA system and is intended to satisfy the growing commercial space market. Like ARA and AIME-II, TRACKER is available in 3, 4, 5, 6, or 7.25-inch disk diameters, with custom sizing available. TRACKER transmits a 24-bit rotary position with the ability to self-calibrate over full and partial revolutions.  TRACKER is available in Commercial & Commercial Space grades that both use commercial electronic components that are selected for their radiation tolerance.

Datasheet CAD Models


Space TRACKER is a variant of the TRACKER encoder that is built with space qualified electronics and is available in either Level 1 or Level 2 grades per EEE-INST-002.  From the user’s perspective, it is identical to TRACKER – it transmits a 24 bit position and is available in the same disk diameters.  Custom disk diameters are always available, simply consult with a Quantic BEI Sales representative.

Datasheet CAD Models

nanoSeries® TRACKER-Lite

The TRACKER-Lite is an evolution of our TRACKER absolute optical encoder. Packaging of the Commercial Space electronics has been optimized to minimize the weight and space claim of this miniscule 24-bit sensor. It is every bit as capable as standard TRACKER, supporting code disk diameters from 3.0″ to in excess of 12.0″.


nanoSeries® Micro Kit Encoder

The Micro Kit Encoder, or MKE, is an absolute kit encoder particularly suited for minimized volume/weight rotary sensing applications. This encoder is sized to mount directly to the aft of many DC motors. Like TRACKER, MKE is available in a commercial space design with inherent radiation tolerance – a perfect solution for CubeSat & SmallSat developers.  The MKE communicates in the same fashion as TRACKER and Space TRACKER.

Datasheet CAD Models

nanoSeries® SPACE Micro Kit Encoder

The SPACE MKE is Quantic BEI’s smallest flight-worthy optical encoder. This absolute optical encoder delivers high performance rotary sensing in a package well suited for CubeSats and small satellites.


nanoSeries® Encoder Test Interface Kit

The nanoSeries Encoder Test Interface Kit provides a means for end users to communicate and control any of Quantic BEI’s nanoSeries encoders. This quick start development kit includes the Encoder Test Box, a test interface cable, and the Encoder Interface Software for use on a personal computer.


nanoSeries® Encoder Drive Stand

The nanoSeries Encoder Drive Stand provides a quick and easy means to mount any nanoSeries kit encoder to establish rotary motion in a laboratory setting. This rotary drive stand comes configured to mate to your particular nanoSeries encoder and gives the user control over speed and direction. When paired with the Encoder Test Interface Kit, it provides a complete setup for laboratory development of nanoSeries encoder systems.


Absolute Housed Encoders

Absolute Housed encoders are designed with either a solid shaft or a “hollow shaft” through-hole. All encoder electronics are contained within the device, giving designers the option to seal these units from dust or moisture. This aspect, coupled with Quantic BEI’s ruggedized bearing assemblies, allows for these sensors to be deployed in any environment. These absolute encoders range from 13 to 30 bits of unambiguous angular position.

LSI μS/16 Series

MicroSeries® Encoders are small, medium resolution absolute shaft encoders with a non-volatile output that have substantially better accuracy than other shaft angle digitizers of similar size. The encoder has an environmentally sealed case and 3-state outputs which can interface directly with a microprocessor. The /16 signifies a nominally 1.6” outer diameter.


LSI μS/23 Series

MicroSeries® Encoders are small, medium resolution absolute shaft encoders with a non-volatile output that have substantially better accuracy than other shaft angle digitizers of similar size. The encoder has an environmentally sealed case and 3-state outputs which can interface directly with a microprocessor. The /23 signifies a nominally 2.3” outer diameter.


nanoSeries® Housed Size 80

The NSH80 offers nanoSeries® AIME-II technology in a rugged, low-profile, hollow shaft bearing assembly. With extreme accuracy and up to 30 bits of resolution, this encoder is suited for the most demanding terrestrial and airborne pointing applications.


5VL690 Optical Resolver Series

L690 Optical Resolvers are absolute optical encoders designed with a solid, hollow, or through shaft. Available from 17 to 22 bits, these rugged encoders are suitable for radar, optical/laser tracking systems, and astronomical telescopes. The natural binary position output is available in either serial or parallel.

Datasheet Datasheet-ER

GCC25 Series

The GCC25 series of absolute encoders are military qualified devices with radiation tolerant components. These rugged encoders meet a variety of environmental requirements such as ballistic shock, vibration, and salt fog exposure.


Absolute Multi-Turn Encoders

Quantic BEI absolute multi-turn encoders provide angular position that represents one revolution per some number of turns of the input shaft. These encoders are manufactured with internal gear boxes that rotate a fine and coarse code disk at different rates per input shaft rotation. Quantic BEI Multi-Turn encoders are found in ground/track military vehicles, submarines, surface ships, and radar installations.

MT40 Series

The 4” Multi-Turn (MT40) is a robust, modular device designed to be impervious to most external non-destructive forces. The MT40 is a highly configurable product with 13 different design parameters to select from. These encoders have a long history of being qualified for military applications and have found use in radar installations.


Incremental Housed Encoders

Quantic BEI incremental housed encoders provide relative angular position between a unique index pulse and the current rotary position. Output formats are available in quadrature square wave or pulse trains in either uni- or bi-directionality. These encoders are available from 5 to 19 bits of resolution.


The Vehicle Motion Sensors (VMS) are devices that convert shaft rotation to distance traveled for wheeled vehicles. The output is used to improve land navigation systems with actual sensed position data. These rugged assemblies are comprised of metal code disks with 32 counts per turn and sense in either forward or reverse direction.

VMS I Datasheet VMS II Datasheet VMS III Datasheet

INC35 & BIC35

These shaft position encoders are available in unidirectional (INC35) or bidirectional (BIC35) versions. These devices have heritage in radar and ground support systems that require resolutions up to 14 bits in a small package.



MIL Series incremental encoders are high reliability, accurate position sensors in a compact package size. The MIL-157, with its 1.5” nominal outer diameter, is a modular device with many options to meet a wide range of requirements. Resolutions are available up to 2048 cycles per turn.



The MIL-257 is the larger version of the MIL-157 at a nominal outer diameter of 2.5”. This allows for resolutions up to 160,000 cycles per turn with the Extended Resolution (ER) option. MIL Series encoders are design to meet stringent military environmental and reliability requirements.