# RLS AksIM-2 Off-Axis Absolute Rotary Encoder

![RLS AksIM-2 Off-Axis Absolute Rotary Encoder](https://parts.trymaglev.com/img/ac-rls-aksim-2.webp)

Thin through-hole absolute magnetic ring encoder (ID 8-68 mm) widely used as the output-side encoder in robot joints and exoskeletons.

- Maglev ID: ac-rls-aksim-2
- Brand: RLS
- MPN: AksIM-2 (MBxxx readhead + MRAxxx ring; configured)
- Category: actuators / Magnetic Encoders
- Origin: SI (maker HQ, factory not confirmed)
- Maker: RLS merilna tehnika d.o.o. (brand, SI)
- NDAA: unknown · Blue UAS: unknown · FCC: n/a
- HTS: 9031.80.80.85 (typical)
- MOQ: unknown · Lead time: unknown
- Confidence: VERIFIED

## Price
- 1+: $238.97 (distributor, 2026-10-29, https://www.mabrobotics.pl/product-page/rls-aksim-2; €221.27 at MAB Robotics (PL) as an MD-controller add-on; configuration not stated; USD at assumed ~1.08 USD/EUR)

## Specifications
- Resolution: 17-bit standard; 18, 19 or 20 bits per rev as high-resolution options depending on ring size (20-bit only on MRA053/064/080; high-res options may contain noise)
- Accuracy: System accuracy ±0.020° (MRA022) to ±0.004° (MRA064/080) with two readheads or after self-calibration; typical installed calibrated ±0.030° to ±0.009°; uncalibrated ±0.100° to ±0.029°
- Max speed: 10,000 rpm (sizes 022/029/039); 9,500 (049); 7,500 (053); 6,000 (064); 4,700 (080)
- Interface: BiSS C; SSI; asynchronous serial (UART); SPI; PWM (RS422 line drivers on serial versions)
- Form: off-axis ring kit (MB readhead + MRA axial magnetic ring; 360° or arc readheads)
- Sensing: unknown
- Supply: 4.5-5.5 V at connector
- Bore: ring ID 8 mm (MRA022) to 68 mm (MRA080DF); e.g. 10, 12.7, 20, 25, 30, 34, 40, 51, 55, 64 mm
- Outer diameter: ring OD 21.5 mm (MRA022) to 95 mm (MRA080DF)
- Multi-turn: yes, 16-bit multiturn counter option (stored; max ±90° rotation while unpowered unless braked)
- Operating temp: -40 to 105 °C (-40 to 85 °C MB022)

## Links
- Product: https://www.rls.si/eng/aksim-2-off-axis-rotary-absolute-encoder
- Datasheet: https://cdn.rls.si/documents/datasheets/MBD01.pdf
- CAD: https://cdn.rls.si/documents/cad-models/MB022_MRA022_3D_files.zip

## Equivalents
- Renishaw RESOLUTE Rotary Readhead, BiSS 32-bit, 150 mm Ring (ac-renishaw-resolute-ra32bba150b30f)
- ZeroErr eCoder11 RS485 Absolute Magnetic Ring Encoder, 11 mm Bore (ac-zeroerr-ecoder11)
- ZeroErr eCoder20 RS485 Absolute Magnetic Ring Encoder, 20 mm Bore (ac-zeroerr-ecoder20)
- ZeroErr eCoder35 RS485 Absolute Magnetic Ring Encoder, 35 mm Bore (ac-zeroerr-ecoder35)
- ZeroErr eCoder65 RS485 Absolute Magnetic Ring Encoder, 65 mm Bore (ac-zeroerr-ecoder65)
- KingKong MPT Series Robot Joint Magnetic Encoder (Single) (ac-kingkong-mpt)
- Novanta IncOder CORE-1-44 Inductive Absolute Angle Encoder (ac-novanta-incoder-core-1-44)
- Novanta IncOder CORE-3-70 Inductive Absolute Angle Encoder (ac-novanta-incoder-core-3-70)
- iC-Haus iC-MU150 EVAL MU1M Off-Axis Encoder Evaluation Kit (2-Track Nonius) (ac-ichaus-ic-mu150-eval-mu1m)
- Netzer DS-25 Hollow-Shaft Absolute Electric Encoder (ac-netzer-ds-25)
- Netzer DS-58 Hollow-Shaft Absolute Electric Encoder (ac-netzer-ds-58)
- RLS Orbis True Absolute Through-Hole Rotary Encoder (ac-rls-orbis)
- RLS AksIM-4 Dual Concentric Off-Axis Absolute Encoder (ac-rls-aksim-4-dual-concentric)
- RLS AksIM-2 Redundant Off-Axis Absolute Encoder (two readheads) (ac-rls-aksim-2-redundant)
- RLS AksIM-4 HIPERFACE DSL Off-Axis Absolute Encoder (53 / 80 mm ring) (ac-rls-aksim-4-hdsl)
- Lika SMAR4 Super-Miniature Off-Axis Absolute Modular Magnetic Encoder (ac-lika-smar4)

## Works with
- MyActuator RMD-X8-P20-120 Planetary Actuator (ac-myactuator-rmd-x8-p20-120)
- CubeMars AK80-64 KV80 Robotic Actuator (ac-cubemars-ak80-64)
- Harmonic Drive CSF-17-100-2UH Strain-Wave Gear Unit (ac-harmonicdrive-csf-17-100-2uh)
- Leaderdrive LCS-17-100 Cup-Type Strain-Wave Reducer (ac-leaderdrive-lcs-17-100)
- Leaderdrive LCSG-17-100 Cup-Type Strain-Wave Reducer (ac-leaderdrive-lcsg-17-100)

## Sources
- https://www.rls.si/eng/aksim-2-off-axis-rotary-absolute-encoder (resolution, interfaces, ring sizes, datasheet/CAD)
- https://www.mabrobotics.pl/product-page/rls-aksim-2 (EUR price)
- https://cdn.rls.si/documents/datasheets/MBD01.pdf (AksIM-2 datasheet MBD01: resolutions per ring, accuracy table, max speed per size, ring IDs/ODs, supply, temperature, interfaces)