Optical absolute encoder
POSITAL IXARC Ethernet absolute encoders
IXARC absolute rotary encoders with PROFINET, EtherNet/IP, EtherCAT or Modbus/TCP, in optical and magnetic versions; optical versions resolve up to 16 bits per turn and 16,384 turns (14-bit multi-turn).
Key specifications
| Ingress protection | up to IP67 (shaft and connector seals, PROFINET page) |
|---|---|
| Data / bus | PROFINET, EtherNet/IP, EtherCAT, Modbus/TCP |
| Supply | 10–30 V DC (EtherCAT version) |
| Resolution (max) | 30 bit |
| Resolution | optical: up to 16 bit single-turn (65,536 steps) + up to 14 bit multi-turn (16,384 revolutions) |
| Profiles | PROFINET encoder profile V4.0/V4.1; EtherCAT CiA DS406 |
| Multiturn | magnetic versions use Wiegand-effect energy harvesting (no battery, no gears); optical multi-turn uses geared code discs |
| Housing | stainless steel housings available |
Summarised in our own words from FRABA B.V. (FRABA Group; CEO and principal shareholder Christian Leeser)'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1 · Source 2 · Source 3
Notes on this data
Line contains optical and magnetic models; classed optical-absolute because the published resolution figures are for the optical versions. Magnetic resolution not stated in the pages read. Temperature and speed not stated.
Specify Motion is not affiliated with FRABA B.V. (FRABA Group; CEO and principal shareholder Christian Leeser). POSITAL and IXARC Ethernet absolute encoders 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 POSITAL part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These series from our supply network is the closest match on published figures.
Multi-turn absolute hollow-shaft capacitive encoder that holds position through power loss, so no re-homing.
| Published maximum | IXARC Ethernet absolute encoders | VLM |
|---|---|---|
| Resolution | 30 bit | 32 bit 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 POSITAL IXARC Ethernet absolute encoders
Send these with your enquiry and an engineer can confirm the right IXARC Ethernet absolute encoders 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
POSITAL IXARC Ethernet absolute encoders: frequently asked questions
What is the POSITAL IXARC Ethernet absolute encoders?
IXARC absolute rotary encoders with PROFINET, EtherNet/IP, EtherCAT or Modbus/TCP, in optical and magnetic versions; optical versions resolve up to 16 bits per turn and 16,384 turns (14-bit multi-turn). Published series figures include resolution 30 bit. It is made by FRABA B.V. (FRABA Group; CEO and principal shareholder Christian Leeser); Specify Motion can help source it or propose an equivalent.
Who makes the POSITAL IXARC Ethernet absolute encoders?
The POSITAL IXARC Ethernet absolute encoders is made by POSITAL (FRABA B.V. (FRABA Group; CEO and principal shareholder Christian Leeser)) and is listed here for engineers comparing options. Specify Motion is not affiliated with FRABA B.V. (FRABA Group; CEO and principal shareholder Christian Leeser); brand names are used only to identify the product.
What is the resolution of the POSITAL IXARC Ethernet absolute encoders?
The published series maximum resolution is 30 bit. Individual models and sizes in the IXARC Ethernet absolute encoders 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 POSITAL IXARC Ethernet absolute encoders?
Yes. On published figures, Netzer Precision VLM is 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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