In short:Magnetic, capacitive and inductive encoders from other makers can replace many Renishaw and RLS encoders where the application's accuracy, resolution, protocol and environment allow; for the highest-resolution optical metrology the technology itself differs, so equivalence must be checked against the real error budget.
What Renishaw makes
Renishaw plc is a UK engineering and metrology group whose position encoders are widely designed into precision stages, machine tools and robotic axes. Renishaw and its product names are trademarks of their owner.
Its open optical encoders include the absolute RESOLUTE and EVOLUTE systems and the incremental QUANTiC, TONiC, VIONiC, ATOM and ATOM DX. The FORTiS range adds enclosed linear encoders for machine tools. Through its associate company RLS, Renishaw also supplies magnetic encoders such as AksIM, RM08, RMB30, RE16, LinACE and HiLin, used in robotics, heavy machinery, surgical systems and aerospace.
Why engineers look for a Renishaw alternative
- Lead time on a particular read head, scale length or interface variant.
- Second source for a part used in volume production.
- Budget, where the application does not need optical metrology performance.
- Environment. Some axes see oil, coolant, dust or vibration that suits a magnetic, capacitive or inductive encoder better.
- Form factor, such as a thin hollow-shaft ring for a robot joint with cabling through the middle.
What to check before treating an encoder as equivalent
- Absolute or incremental. And for absolute, single or multi-turn. Our absolute vs incremental guide covers the choice.
- Accuracy and resolution. Accuracy at the load is what matters; resolution only sets the smallest step the control loop sees.
- Interface. BiSS-C, SSI, quadrature or a drive-specific protocol, with the bit count and update rate.
- Mounting tolerance. Ride height, yaw, pitch and roll limits, and how the head is aligned on installation.
- Speed. Maximum speed at the chosen resolution.
- Scale. Length, thermal expansion, mounting method and reference marks.
- Environment. Temperature, contamination, IP rating, shock and vibration.
- Size. Read head envelope, ring OD and bore.
Our encoder selection guide explains how to build an error budget before comparing parts.
A useful habit: write down where the encoder sits in the mechanics. An encoder on the motor shaft sees backlash and wind-up filtered by the gearing, while one on the load sees every error directly. Moving from a load-side optical encoder to a motor-side magnetic one changes the whole control loop, not just the part number.
Encoder alternatives in our supply network
Rotary. Netzer’s capacitive Electric Encoders are thin hollow-shaft rings with SSI or BiSS-C output: the VLX for general robotics and automation, the VLP for harsh environments, tested to MIL-STD-810, the VLT rated from −55 to +125 °C, and the VLM multi-turn, which keeps position through power loss. The Novanta Midi Ultra IncOder is an inductive absolute encoder from 75 to 300 mm OD with up to 22-bit resolution.
Linear. The Bogen ALS21 absolute magnetic read head reads LMSA scales at 1 µm resolution to IP67, and the IKS23 incremental head is a rugged RS422 or HTL option. KappaSense’s FREEe capacitive absolute linear encoder has a passive read head with no moving cables and a published accuracy of ±5 µm.
Magnetic heads for OEM integration. The Bogen AKS17 offers 21 to 24-bit absolute resolution on linear and rotary scales.
See the encoders hub for the full range.
How the comparison works
The table under this text compares each Renishaw and RLS series we hold data for with the closest product from our supply network, on published figures only. “Equivalent” means a product that meets the stated specification for your application, confirmed by an engineer; magnetic, capacitive and inductive encoders are a different technology from optical ones, not identical parts. Specify Motion is not affiliated with, authorised by or endorsed by Renishaw or RLS, and no logos are used. Names identify products only.
If your axis needs Renishaw-class optical accuracy, we will tell you rather than propose something that falls short.
Renishaw series and the closest match from our supply network
Each row compares the highest published figures for the series. A match here is a starting point: an engineer confirms the fit for your load, duty, mounting and interface before recommending anything.
| Renishaw series | Type | Closest match |
|---|---|---|
| ATOM | Optical incremental encoder | Ask an engineer |
| ATOM DX | Optical incremental encoder | Ask an engineer |
| EVOLUTE | Optical absolute encoder | Ask an engineer |
| FORTiS-N | Enclosed linear encoder | Bogen ALS21 meets or exceeds the figures compared Meets or exceeds the figure compared |
| FORTiS-S | Enclosed linear encoder | Bogen ALS21 meets or exceeds the figures compared Meets or exceeds the figure compared |
| QUANTiC | Optical incremental encoder | Ask an engineer |
| RESOLUTE | Optical absolute encoder | Netzer Precision VLM meets or exceeds the figures compared Meets or exceeds the figure compared |
| RLS AksIM-4 | Magnetic encoder | Netzer Precision VLP meets or exceeds the figures compared Meets or exceeds the figure compared |
| RLS HiLin | Magnetic encoder | Ask an engineer |
| RLS LinACE InAxis | Magnetic encoder | Ask an engineer |
| RLS RE16 | Magnetic encoder | Ask an engineer |
| RLS RM08 | Magnetic encoder | Netzer Precision VLP meets or exceeds the figures compared Meets or exceeds the figure compared |
| RLS RMB30 | Magnetic encoder | Netzer Precision VLP meets or exceeds the figures compared Meets or exceeds the figure compared |
| TONiC | Optical incremental encoder | Bogen ALS21 meets or exceeds the figures compared Meets or exceeds the figure compared |
| VIONiC | Optical incremental encoder | Bogen ALS21 meets or exceeds the figures compared Meets or exceeds the figure compared |
Specify Motion is not affiliated with Renishaw plc. Brand and series names are used only to identify products. Comparisons use published figures; always confirm against the current datasheet.
Frequently asked questions
Can a magnetic or capacitive encoder replace a Renishaw optical encoder?
It depends on what the axis needs. Optical encoders such as RESOLUTE or TONiC reach very fine resolution and accuracy, while magnetic, capacitive and inductive encoders trade some of that for tolerance of dirt, oil, wider mounting gaps or temperature. If your error budget allows the alternative's accuracy, the change can improve robustness. If you are working at sub-micron accuracy, keep optical.
Do encoder alternatives support BiSS-C and SSI?
Many do. BiSS-C and SSI are open serial protocols widely used by encoder makers, so a drive that reads one encoder over BiSS-C can often read another. Check the bit count, the CRC and timing settings, the supply voltage and whether you need extra data such as temperature or warnings. Drive-specific protocols need a matching variant.
What is the RLS connection to Renishaw?
Renishaw describes RLS as its associate company and supplies magnetic encoder systems and components through it. RLS products such as AksIM, RM08, RMB30 and LinACE are therefore often grouped with Renishaw parts on drawings and bills of materials. Alternatives for those magnetic encoders are compared in the same way as for optical ones.
What should I send to get a Renishaw equivalent proposed?
Send the read head and scale part numbers, the protocol and resolution, the accuracy you actually need at the load, the axis length or ring diameter, speed, mounting space and ride height, temperature, contamination, IP rating and the drive or controller the encoder connects to. Photographs of the installed encoder help with older parts.
Sources
- Renishaw: optical encoder product comparison table
- Renishaw: magnetic encoders (supplied through associate company RLS)
Figures are summarised from the sources above and from manufacturers' published data on the date shown. Always confirm against the current datasheet for your exact part.