Optical incremental encoder
Renishaw TONiC optical incremental encoder
Compact 20 µm-pitch incremental optical encoder with an interface box offering interpolation down to 1 nm. Works with linear tape, spar, partial arc and rotary ring scales for dynamic precision stages.
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What are you specifying?
Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Outer diameter | 52–550 mm |
|---|---|
| Ingress protection | IP40 |
| Linear speed (max) | 10 m/s |
| Resolution (finest) | 1 nm |
| Accuracy | RELM20 ±1 µm/m; RTLC20/RKLC20-S ±5 µm/m; rotary ±4.3 to ±0.5 arc sec (RESM20/REXM20) |
| Interface | RS422 digital, 1 Vpp analogue |
Summarised in our own words from Renishaw plc's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1 · Source 2 · Source 3
Notes on this data
Readhead 35 x 13.5 x 10 mm, IP40 (interface IP20); operating 0 to +70 °C. SDE typically ±30 nm. Rotary up to 3,673 rpm. Variants: Functional Safety, UHV, DOP dual output, DSi dual-readhead angle system. od_mm = RESM20 ring range (REXM20 52-417 mm).
Specify Motion is not affiliated with Renishaw plc. Renishaw and TONiC are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Renishaw TONiC replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original Renishaw part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
Absolute linear magnetic read head for LMSA scales, 1 µm resolution, up to 10 m/s, IP67.
| Published maximum | TONiC | ALS21 |
|---|---|---|
| Speed | 10 m/s | 10 m/s meets or exceeds |
Rugged incremental head with RS422 or HTL output and 10-30 VDC supply option. Works on linear and rotary scales.
| Published maximum | TONiC | IKS23 |
|---|---|---|
| Speed | 10 m/s | 16 m/s meets or exceeds |
Robust capacitive linear encoder with wide mounting tolerances for vibrating, dirty or hot environments, strokes to 1.9 m.
| Published maximum | TONiC | FLEXe |
|---|---|---|
| Speed | 10 m/s | 10 m/s meets or exceeds |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
Typical applications
What an optical incremental encoder is
An optical incremental encoder measures motion by shining light through or reflecting it from a disc or scale with fine graduations onto photodetectors. As the disc or scale moves, the encoder outputs two square-wave or sine-wave channels in quadrature, called A and B, plus an index pulse once per revolution or at reference marks. The counter in the drive or controller tracks position by counting edges from a home point. Optical encoders achieve very high resolution and accuracy.
When engineers choose an optical incremental encoder
Choose an optical incremental encoder for precise speed and position feedback where homing at power-up is acceptable, such as servo motors, stages and machine tools. They are widely compatible and cost effective. The trade-offs are contamination and power loss: dust, oil and condensation can obscure the optical path, and position is lost when power is removed. For harsh environments, magnetic or inductive encoders may suit better.
How to specify the Renishaw TONiC
Send these with your enquiry and an engineer can confirm the right TONiC variant or an equivalent:
- Resolution (lines per revolution or µm)
- Output type: TTL, HTL or sin/cos
- Index or reference marks
- Shaft or hollow shaft size (mm)
- Maximum speed (rpm or m/s)
- Supply voltage (V)
- Environment and IP code
Common mistakes to avoid
- Choosing resolution above what the drive input can count
- Running long cables with TTL signals without line drivers
- Ignoring contamination in open optical designs
- Forgetting homing routines after power-up
Renishaw TONiC: frequently asked questions
Can you help replace Renishaw TONiC or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the Renishaw TONiC?
Compact 20 µm-pitch incremental optical encoder with an interface box offering interpolation down to 1 nm. Works with linear tape, spar, partial arc and rotary ring scales for dynamic precision stages. Published series figures include outer diameter 52 mm, outer diameter 550 mm, linear speed 10 m/s, resolution (finest) 1 nm. It is made by Renishaw plc; Specify Motion can help source it or propose an equivalent.
Who makes the Renishaw TONiC?
The Renishaw TONiC is made by Renishaw (Renishaw plc) and is listed here for engineers comparing options. Specify Motion is not affiliated with Renishaw plc; brand names are used only to identify the product.
What is the outer diameter of the Renishaw TONiC?
The published series minimum outer diameter is 52 mm. Individual models and sizes in the TONiC range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the Renishaw TONiC?
We can assess suitable replacement options. On published figures, Bogen ALS21 and Bogen IKS23 are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
What is quadrature output on an incremental encoder?
Quadrature output provides two channels, A and B, offset by 90 electrical degrees. Comparing which leads gives direction, and counting edges on both gives four times the line count in resolution. An index pulse marks a reference position for homing.
What is the difference between TTL and HTL outputs?
TTL outputs use a 5 V differential signal, which suits high frequencies and is commonly used with line drivers. HTL outputs use a higher voltage swing, typically matched to a 10 to 30 V supply, which improves noise immunity on long cables. Match the output type to the drive or controller input.
Further reading: Absolute vs incremental encoders · How to select an encoder · Encoders and feedback
Other optical incremental encoder series
Engineer support
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Tell us how you use the Renishaw TONiC: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.
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Prefer to configure it? Use the spec builder.
How it works
From enquiry to delivery
Send a part number or describe the application. Our engineers take it from there: the right product, a clear quotation, and delivery and support arranged.
- 01Tell us what you needSend a part number, or configure the application, quantities and timing.
- 02An engineer reviews itWe check the specification and find the original part, a checked equivalent or a complete axis.
- 03Receive your quotationProducts, pricing, lead time and compatibility notes in one reply.
- 04Order and deliveryWhen you are happy, the order is placed and delivery and after-sales support are arranged.