# ZeroErr eCoder20 RS485 Absolute Magnetic Ring Encoder, 20 mm Bore

![ZeroErr eCoder20 RS485 Absolute Magnetic Ring Encoder, 20 mm Bore](https://parts.trymaglev.com/img/ac-zeroerr-ecoder20.webp)

ZeroErr's 20 mm through-hole magnetic ring encoder with RS-485, single- or multi-turn, for mid-size joints that route cables through the axis.

- Maglev ID: ac-zeroerr-ecoder20
- Brand: ZeroErr
- MPN: eCoder20
- Category: actuators / Magnetic Encoders
- Origin: CN (maker HQ, factory not confirmed)
- Maker: ZeroErr (brand, CN)
- NDAA: unknown · Blue UAS: unknown · FCC: n/a
- HTS: 9031.80.80.85 (typical)
- MOQ: unknown · Lead time: unknown
- Confidence: REPORTED

## Price
- 1+: $259 (distributor, 2026-10-30, https://rcdrone.top/products/zeroerr-ecoder20-magnetic-encoders; single-turn RS485 variant)
- 1+: $180 (distributor, 2026-10-30, https://aifitlab.com/products/zeroerr-ecoder20-magnetic-encoders; single-turn RS485 variant; backordered at this seller)

## Specifications
- Resolution: 19 bit (ZeroErr product page); family 17-21 bit + optional 16-bit multiturn counter (manual)
- Accuracy: <0.06° maximum absolute tolerance with well-centred ring (manual Table 7-1); self-calibration recommended after install; repeatability ±10"
- Max speed: 12,000 rpm
- Interface: RS-485 asynchronous serial, 2.5 Mbps (request/response frames with CRC)
- Form: off-axis ring kit (axial-reading magnetic ring + readhead)
- Sensing: unknown
- Supply: 4.7-5.4 V
- Bore: 20 mm ring ID (readhead ID 22 mm)
- Outer diameter: 33.5 mm ring OD; readhead OD 34 mm
- Multi-turn: yes, optional 16-bit multiturn counter with 3.6 V battery backup (eCoder xx M-RxxB)
- Operating temp: -40 to +85 °C (product page); manual says -40 to +105 °C

## Links
- Product: https://rcdrone.top/products/zeroerr-ecoder20-magnetic-encoders
- Datasheet: none
- CAD: none

## Equivalents
- RLS AksIM-2 Off-Axis Absolute Rotary Encoder (ac-rls-aksim-2)
- ZeroErr eCoder11 RS485 Absolute Magnetic Ring Encoder, 11 mm Bore (ac-zeroerr-ecoder11)
- KingKong MPT Series Robot Joint Magnetic Encoder (Single) (ac-kingkong-mpt)
- Netzer DS-58 Hollow-Shaft Absolute Electric Encoder (ac-netzer-ds-58)
- ZeroErr eCoder18 RS485 Absolute Magnetic Ring Encoder, 18 mm Bore (ac-zeroerr-ecoder18)
- ZeroErr eCoder45 RS485 Absolute Magnetic Ring Encoder, 45 mm Bore (ac-zeroerr-ecoder45)
- ZeroErr eCoder35H RS485 Absolute Magnetic Ring Encoder, 35 mm Bore (ac-zeroerr-ecoder35h)

## Sources
- https://rcdrone.top/products/zeroerr-ecoder20-magnetic-encoders (variants, price, <0.06° tolerance, ±10" repeatability, 12,000 rpm)
- https://aifitlab.com/products/zeroerr-ecoder20-magnetic-encoders (price, ring/readhead dimensions, stock)
- https://www.zeroerr.com/magnetic_encoders/ecoder20 (maker page: ID/OD, 19 bit, repeatability, 12000 rpm, RS485, temperature)
- https://dl.zeroerr.cn/static/en/ZeroErr_eCoder_Manual_Ver2.6.pdf (eCoder manual v2.6: accuracy table, supply 4.7-5.4 V, 17-21 bit, multiturn battery, 2.5 Mbps RS485)