In automation, accuracy isn’t just nice to have; it’s essential. Whether you’re operating a crane, a robotic arm or a production line, reliable position feedback helps keep things safe, efficient, and running without interruptions. That’s where absolute encoders come in.
Unlike incremental encoders that only track movement, absolute encoders know exactly where they are at all times. Even after a power cut. No need to recalibrate. No wasted time.
At Euro HÜBNER Benelux B.V., we supply Baumer encoders designed for demanding industrial settings. In this article, we’ll show you how absolute encoders work, where they’re used, and how to choose the right one for your setup.
How absolute encoders work
Absolute encoders provide exact position feedback by assigning a unique digital value to every shaft position. Unlike incremental encoders that count pulses as the shaft moves, absolute encoders always know their position, even after power loss. That’s what makes them essential in systems where accuracy, uptime, and safety can’t be compromised.
So, how do they do it?
Inside the encoder, a rotating disc is divided into coded tracks. As the shaft turns, light (or magnetism, in some models) passes through or reflects off these tracks and is read by sensors. Each position on the disc corresponds to a distinct binary value. This means the encoder outputs a precise signal representing the shaft’s position at any moment. No need to move or reset the system to find a reference point.
There are two main types of absolute encoders: single-turn and multi-turn.
- Single-turn encoders measure position within one full revolution of the shaft. They’re ideal for applications with limited rotational range, like robotics or packaging machines.
- Multi-turn encoders go a step further by also counting the number of full revolutions, making them perfect for cranes, hoists, or presses – where position tracking over many rotations is crucial.
Modern absolute encoders often use digital interfaces like SSI, CANopen, or PROFINET to transmit data directly to PLCs or control systems with high reliability.
In short, absolute encoders combine digital precision with mechanical resilience, making them the go-to choice for industrial automation, motion control, and safety-critical systems. When you need feedback that doesn’t forget -even when the power goes out- absolute encoders are the answer.
Also read: SSI encoders explained, for more detailed information about this specific interface.
Absolute vs incremental encoders
When choosing between absolute and incremental encoders, it’s all about what your system needs. Both devices measure motion, but they do it differently, and that makes a big difference in real-world use.
Incremental encoders track movement by generating pulses as the shaft rotates. Your control system counts these pulses to calculate position, speed, or direction. But when the power is cut or the system restarts, that data disappears. You’ll need a reference point or homing routine to recalibrate.
Absolute encoders, on the other hand, assign a unique digital value to each position. That means they always know their exact position, even after a power loss. There’s no need to reset or recalibrate. This is crucial in applications where safety, precision, or uptime are non-negotiable.
Our article: the difference between absolute and incremental encoders gives a more detailed explanaition so make sure to read!
If your application only requires relative motion tracking, like monitoring speed or simple direction, an incremental encoder might be enough and more cost-effective. But if your system needs continuous, exact position feedback with no room for error, absolute is the smarter choice.
Comparison table: Absolute vs incremental encoders
| Feature | Absolute Encoder | Incremental Encoder |
| Position on startup | Known instantly | Unknown until homed |
| Data after power loss | Retains exact position | Loses all position info |
| Output signal | Unique digital value | Pulse-based signals |
| Recalibration needed? | No | Yes |
| Best for | High-precision, safety-critical systems | Basic speed/direction tracking |
| Common applications | Cranes, robotics, automation | Conveyors, fans, low-cost applications |
| Cost | Higher | Lower |
Interface and communication options
For your encoder to work seamlessly with your system, it needs to communicate using a compatible interface. Whether your setup uses a PLC, drive, or industrial network, choosing the right protocol, like SSI, CANopen, PROFIBUS, or PROFINET, ensures that position data is transmitted accurately and without delays.
- SSI (Synchronous Serial Interface) – Reliable, low-latency, point-to-point.
- CANopen, PROFIBUS, PROFINET – Designed for industrial networks.
Baumer supports these protocols and comes in rugged housings with IP protection that is available via Euro HÜBNER Benelux B.V.
If you’re not sure which one fits your setup, our engineers can help you select the right match to avoid errors, simplify installation, and maximise system performance.
Where absolute encoders are used
Absolute encoders are built for environments where accuracy, consistency, and durability are non-negotiable. You’ll often find them in demanding industrial setups where real-time position feedback is essential.
Here are some common applications:
- Cranes and lifting systems
They track the exact position of hoists and trolleys, helping to prevent collisions and positioning errors during lifts. - Robotic arms and automation
Encoders provide constant joint position feedback, allowing robots to move with precision and repeatability—even after a power cycle. - Marine and offshore environments
These encoders are engineered to survive harsh conditions like salt spray, humidity, and strong vibrations, making them ideal for ship drives or offshore winches. - Tension and web control
Integrated with web guide systems, absolute encoders help keep materials like film or fabric perfectly aligned during high-speed processing. - Force and load monitoring
When paired with force measurement systems, they support real-time control and feedback in press systems or load-bearing machinery.
In many of these setups, absolute encoders are used alongside electromagnetic brakes or tacho generators to create a complete motion and feedback solution.
Encoder resolution and mechanical design
The resolution of an absolute encoder tells you how precise it is. Single-turn models usually offer 12–18 bits. Multi-turn versions can go past 30 bits. That means tiny positional changes get picked up, which is essential in robotics, wind turbines, or packaging lines.
Baumer encoders are built to last: sealed housings, reinforced bearings, and shock-resistant construction. Euro HÜBNER Benelux B.V. offers solid and hollow shaft models to fit a wide range of machines, whether new or retrofit.
How to choose the right absolute encoder
Choosing the right absolute encoder depends on how your machine moves, how much precision you need, and where the encoder will be working. Here’s what to look at:
- Type of motion
Is your system moving in a straight line (linear) or rotating? Some encoders are better suited for one or the other. - Measurement range
Do you only need to track one full rotation (single-turn), or do you need to keep count over multiple turns (multi-turn)? Multi-turn encoders are ideal for cranes, hoists, or any system with extended motion. - Communication interface
What does your PLC or drive system use: SSI, CANopen, PROFIBUS, or PROFINET? Matching the right protocol avoids headaches during setup. - Resolution
How precise does the position data need to be? Higher resolution gives you finer detail but may require more processing power. - Operating environment
Will the encoder face dust, heat, vibration, or moisture? Choose a model with the right IP rating and mechanical protection. - Mounting and fit
Check the shaft type (solid or hollow), available space, and alignment needs. The mechanical design must match your setup to avoid unnecessary wear.
Still unsure? Our engineers are happy to help you narrow down the options and choose a model that fits your machine. Don’t hesitate to contact us!
Why choose Euro HÜBNER Benelux B.V.
We’re a trusted supplier of motion control components, including absolute and incremental encoders, tacho generators, and force measurement systems.
As Baumer’s official partner, we combine premium German tech with local expertise. Whether it’s a replacement part or a new system, we support you from first advice to final install.
Key takeaways
- Absolute encoders remember their position, even after shutdown.
- Multi-turn versions track movement across full ranges.
- Available with SSI and industrial network interfaces.
- Ideal for cranes, robotics, marine, and more.
- We offer durable Baumer models with local support.
Frequently asked questions (FAQs)
What is the difference between an absolute encoder and an incremental encoder?
An absolute encoder provides a unique position value at any given point, even after power loss. Incremental encoders only track movement and lose position data if power is cut.
Where are absolute encoders used?
They are used in applications that require reliable, precise position feedback, such as cranes, robotics, offshore systems, and packaging machines.
What is a multi-turn encoder?
A multi-turn encoder not only records position within a single revolution but also counts the total number of revolutions, ideal for systems with extended motion.
Which interface protocols are common for absolute encoders?
SSI is the most common, but other supported interfaces include CANopen, PROFIBUS, and PROFINET, depending on your control system.
How do I choose the right absolute encoder?
Consider factors like motion type, resolution, communication protocol, mechanical fit, and environmental conditions. Our experts can help you configure the right model.