# ZeroErr eCoder18 RS485 Absolute Magnetic Ring Encoder, 18 mm Bore

![ZeroErr eCoder18 RS485 Absolute Magnetic Ring Encoder, 18 mm Bore](https://parts.trymaglev.com/img/ac-zeroerr-ecoder18.webp)

Axial-reading off-axis ring + readhead absolute encoder from ZeroErr, 18 mm bore; sits between the listed eCoder11 and eCoder20 for small humanoid and arm joints.

- Maglev ID: ac-zeroerr-ecoder18
- Brand: ZeroErr
- MPN: eCoder18
- Category: actuators / Magnetic Encoders
- Origin: CN (maker HQ, factory not confirmed)
- Maker: ZeroErr (Beijing ZeroErr Technology) (brand, CN)
- NDAA: unknown · Blue UAS: unknown · FCC: n/a
- HTS: 9031.80.80.85 (typical)
- MOQ: unknown · Lead time: unknown
- Confidence: VERIFIED

## Price
- 1+: $180 (reported, 2026-10-30, https://aifitlab.com/products/zeroerr-ecoder18-magnetic-encoders; single-turn RS485 variant, aifitlab (US reseller) price)
- 1+: $200 (reported, 2026-10-30, https://aifitlab.com/products/zeroerr-ecoder18-magnetic-encoders; multiturn RS485 variant without battery)

## Specifications
- Resolution: up to 19 bit (series 17 to 21 bit options); 16 bit multiturn counter option
- Accuracy: max absolute tolerance <0.06° (retailer copy of ZeroErr table); repeatability ±10"
- Max speed: 12,000 rpm
- Interface: Asynchronous serial RS485 (8-pin connector)
- Form: off-axis ring kit: magnetic ring + readhead (360° arc readhead)
- Sensing: magnetic, axial reading (sensor type not stated)
- Supply: 4.7 V to 5.4 V (retailer copy of ZeroErr table)
- Bore / ring ID: 18 mm ring ID
- Outer diameter: 33.5 mm ring OD; readhead OD 34 mm
- Multiturn: optional, battery-backed counter (3.6 V battery)
- Operating temp: -40 to +85 °C (ZeroErr page)

## Links
- Product: https://en.zeroerr.cn/magnetic_encoders/ecoder18
- Datasheet: https://dl.zeroerr.cn/static/en/ZeroErr_eCoder_Manual_Ver2.6.pdf
- CAD: none

## Equivalents
- 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)

## Sources
- https://en.zeroerr.cn/magnetic_encoders/ecoder18 (official product data: bore, OD, thickness, resolution, repeatability, speed, RS485, temp)
- https://aifitlab.com/products/zeroerr-ecoder18-magnetic-encoders (retailer: USD prices per variant, availability, accuracy/supply table, images)
- https://dl.zeroerr.cn/static/en/ZeroErr_eCoder_Manual_Ver2.6.pdf (eCoder manual)