Optical absolute encoder
TR-Electronic CD_75 safety absolute encoders (SIL3/PLe)
Absolute multiturn safety encoders certified to SIL3 and PLe from 75 mm, in hollow or solid shaft, with PROFIsafe (PROFIBUS or PROFINET), openSAFETY over Powerlink, FSoE or double SSI, and ATEX housing options.
Key specifications
| Data / bus | PROFIsafe via PROFINET, PROFIsafe via PROFIBUS, openSAFETY (Powerlink), FSoE (EtherCAT), double SSI |
|---|---|
| Safety | SIL3 / PLe |
| Housing | 75 |
Summarised in our own words from TR Electronic GmbH's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Notes on this data
Sensing principle, resolution and environmental figures are in the CDH75 brochure (not read); typed as optical absolute, confirm with TR-Electronic.
Specify Motion is not affiliated with TR Electronic GmbH. TR-Electronic and CD_75 safety absolute encoders (SIL3/PLe) are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
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Our experienced engineers are on hand, ready to help with your project. Whether you need the TR-Electronic CD_75 safety absolute encoders (SIL3/PLe) itself, help sourcing it, or a modified or custom design built around your load, speed and space, tell us what the machine has to do and we'll come back with the right option.
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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 TR-Electronic CD_75 safety absolute encoders (SIL3/PLe)
Send these with your enquiry and an engineer can confirm the right CD_75 safety absolute encoders (SIL3/PLe) 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
TR-Electronic CD_75 safety absolute encoders (SIL3/PLe): frequently asked questions
What is the TR-Electronic CD_75 safety absolute encoders (SIL3/PLe)?
Absolute multiturn safety encoders certified to SIL3 and PLe from 75 mm, in hollow or solid shaft, with PROFIsafe (PROFIBUS or PROFINET), openSAFETY over Powerlink, FSoE or double SSI, and ATEX housing options. It is made by TR Electronic GmbH; Specify Motion can help source it or propose an equivalent.
Who makes the TR-Electronic CD_75 safety absolute encoders (SIL3/PLe)?
The TR-Electronic CD_75 safety absolute encoders (SIL3/PLe) is made by TR-Electronic (TR Electronic GmbH) and is listed here for engineers comparing options. Specify Motion is not affiliated with TR Electronic GmbH; brand names are used only to identify the product.
Is there an alternative to the TR-Electronic CD_75 safety absolute encoders (SIL3/PLe)?
Yes. Our engineers can propose an equivalent built around your load, speed and environment. 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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Tell us about your project and how you use the TR-Electronic CD_75 safety absolute encoders (SIL3/PLe): the load, speed, duty and environment. An experienced engineer will review it and reply, normally within one working day.
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