Optical absolute encoder
HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear optical absolute encoder
Exposed absolute linear encoders for long axes, with drive-specific serial protocols and functional-safety and vacuum variants.
Key specifications
| Linear speed (max) | 10 m/s |
|---|---|
| Resolution (finest) | 1 nm |
| Interface | EnDat, Fanuc, Mitsubishi, Panasonic, Yaskawa |
| Measuring length max | 28,000 |
Summarised in our own words from DR. JOHANNES HEIDENHAIN GmbH's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1 · Source 2
Notes on this data
LIC 4100: up to 28 m, resolution down to 1 nm, up to 600 m/min (10 m/s, converted). Variants Dplus, FS (functional safety), V (vacuum). Accuracy grade not on page.
Specify Motion is not affiliated with DR. JOHANNES HEIDENHAIN GmbH. HEIDENHAIN and LIC 2100 / 3100 / 4100 exposed absolute linear are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a HEIDENHAIN part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Absolute linear magnetic read head for LMSA scales, 1 µm resolution, IP67.
| Published maximum | LIC 2100 / 3100 / 4100 exposed absolute linear | ALS21 |
|---|---|---|
| Speed | 10 m/s | 15 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 | LIC 2100 / 3100 / 4100 exposed absolute linear | 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 | LIC 2100 / 3100 / 4100 exposed absolute linear | 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.
What an optical absolute encoder is
An optical absolute encoder reads a unique code pattern on a disc or scale, so every position has its own digital value and position is known immediately at power-up. Single-turn encoders give position within one revolution; multi-turn encoders also count revolutions using gears or electronic counters. Position is sent over a serial interface such as SSI or BiSS, a manufacturer-specific protocol, or a fieldbus. Optical scanning gives high resolution, typically 17 bits per revolution or more in servo encoders, and good accuracy.
When engineers choose an optical absolute encoder
Choose an optical absolute encoder where knowing position at power-up matters, such as robots, machine tools, multi-axis machines and axes that cannot be homed safely. It removes homing routines and supports safety functions. The trade-offs are cost, interface compatibility and contamination sensitivity. Battery-backed multi-turn types need battery maintenance; gear or energy-harvesting types avoid that. In very dirty environments, magnetic or inductive absolute encoders may suit better.
How to specify the HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear
Send these with your enquiry and an engineer can confirm the right LIC 2100 / 3100 / 4100 exposed absolute linear variant or an equivalent:
- Single-turn resolution (bits)
- Multi-turn range (revolutions)
- Interface: SSI, BiSS, proprietary serial or fieldbus
- Accuracy (arcsec)
- Shaft or hollow shaft size (mm)
- Speed (rpm)
- Environment and safety rating
Common mistakes to avoid
- Choosing an interface the drive does not support
- Forgetting battery maintenance on battery-backed multi-turn types
- Confusing resolution with accuracy
- Ignoring cable length limits for serial interfaces
HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear: frequently asked questions
What is the HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear?
Exposed absolute linear encoders for long axes, with drive-specific serial protocols and functional-safety and vacuum variants. Published series figures include linear speed 10 m/s, resolution (finest) 1 nm. It is made by DR. JOHANNES HEIDENHAIN GmbH; Specify Motion can help source it or propose an equivalent.
Who makes the HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear?
The HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear is made by HEIDENHAIN (DR. JOHANNES HEIDENHAIN GmbH) and is listed here for engineers comparing options. Specify Motion is not affiliated with DR. JOHANNES HEIDENHAIN GmbH; brand names are used only to identify the product.
What is the linear speed of the HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear?
The published series maximum linear speed is 10 m/s. Individual models and sizes in the LIC 2100 / 3100 / 4100 exposed absolute linear 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 HEIDENHAIN LIC 2100 / 3100 / 4100 exposed absolute linear?
Yes. On published figures, Bogen ALS21 and Bogen IKS23 are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
What is the difference between single-turn and multi-turn absolute encoders?
A single-turn absolute encoder knows its angle within one revolution. A multi-turn absolute encoder also counts complete revolutions, so it knows total position over many turns even after power loss. Multi-turn encoders avoid homing on axes driven through screws or gears.
Which interface should an absolute encoder use?
Use the interface supported by the drive or controller. SSI is simple and widely supported, BiSS-C is an open bidirectional protocol, and several manufacturer-specific protocols are common on machine tools and servo drives. Fieldbus encoders suit PLC networks. Check cable lengths and update rates for the control loop.
Further reading: Absolute vs incremental encoders · How to select an encoder · Encoders and feedback
Other optical absolute encoder series
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