An encoder is a sensor that converts motion into an electrical signal that can be read by a control device. In any application involving rotational movement, an encoder is essential. It provides feedback on position, speed, and direction, which is essential in applications like robotics, CNC machines, elevators, and industrial automation.
When selecting either encoder, incremental or absolute, for your motion control system, understanding their core differences is essential. Both encoder types serve to measure position, speed, and direction, but they do so in distinct ways that impact performance, reliability, and cost. Whether you’re designing a robotic arm, an industrial conveyor, or a CNC machine, choosing the right encoder can make or break your system’s efficiency. Learn more about the working principle of an encoder.
Comparisons between Incremental and Absolute Encoders
When selecting an encoder for your application, understanding the differences between incremental and absolute encoders is crucial. Each type offers distinct advantages depending on your system’s requirements for speed, precision, and reliability.
| Feature | Incremental Encoders | Absolute Encoders |
| How They Work | Generate pulses as shaft rotates; pulses are counted to determine relative position. | Provide a unique digital code for each shaft position, giving absolute position immediately. |
| Output Channels | A, B pulses (for direction), and optional Z-index (reference point) | Digital code representing exact position |
| Pros | – Cost-effective – High resolution – Simple design and integration – Fast response time |
– Retains position after power loss – No need for homing – Ideal for safety-critical systems |
| Cons | – Loses position on power loss – Requires homing at startup – Not ideal for safety-critical use |
– More expensive – Slightly more complex integration – May have lower resolution than high-end incremental encoders |
| Best For | Speed & direction tracking – High-speed applications – Cost-sensitive projects – Systems where position reset is acceptable |
Precise position tracking – Robotics and automation – Safety-critical systems – Applications requiring precise position tracking |
How To Choose the Right Encoder for Your Application?
Choosing between incremental and absolute encoders isn’t just a matter of preference, it’s about aligning the encoder’s capabilities with your application’s technical and operational requirements. Let’s break down the decision-making process based on key factors:
1. Application Type and Complexity
- Incremental Encoders are ideal for straightforward applications where relative position tracking is sufficient. These include conveyor systems, basic motor control, and speed monitoring.
- Absolute Encoders shine in complex systems like multi-axis robotics, automated guided vehicles (AGVs), and medical devices, where precise and continuous position data is critical, even after power interruptions.
2. Power Loss and Position Retention
- Incremental Encoders lose track of position when power is cut. This means the system must perform a homing sequence at startup to recalibrate.
- Absolute Encoders retain position data even when power is lost, thanks to their unique digital coding for each shaft position. This makes them indispensable in systems where downtime or recalibration is costly or impractical.
3. Safety and Reliability Requirements
- In safety-critical environments, such as elevators, surgical robots, or aerospace systems, absolute encoders are preferred because they provide reliable, real-time position data without needing to reset.
- Incremental encoders, while reliable in many industrial settings, may not meet the stringent safety standards required for these applications.
4. Budget Constraints
- Incremental Encoders are generally more affordable and easier to integrate, making them a popular choice for cost-sensitive projects.
- Absolute Encoders come at a higher price point due to their advanced functionality, but the investment is often justified by the added reliability and reduced maintenance.
5. Speed and Resolution Needs
- If your application demands high-speed feedback, such as in printing presses or high-speed sorting machines, incremental encoders typically offer higher resolution and faster response times.
- Absolute encoders can also provide high resolution, especially in multi-turn variants, but may not match the speed performance of top-tier incremental models.
In summary, the choice between incremental and absolute encoders depends on your application’s needs:
- Choose incremental if you need high-speed feedback and can tolerate position loss on power-down.
- Choose absolute if you need precise, reliable position data at all times, especially in safety-critical or complex systems.
Both incremental and absolute encoders have their place in modern automation. By understanding their differences and evaluating your application’s requirements, you can select the encoder that delivers the best performance, reliability, and value.
At Transtech, we offer a wide range of encoders, including heavy-duty and industrial encoders from world-leading supplier such as Baumer-Hubner. Contact us today to get help on selecting the right encoder or get one tailored for your application.