1.What Is an Encoder?
In automation, mechatronics, robotics, and instrumentation, position, displacement, speed, and direction must be measured precisely.
An encoder converts mechanical motion or rotation into an electrical signal — it’s essentially a translator between movement and digital data, telling the control system how far and in which direction something has moved.
Among the different types, the two most common are:
2. Working Principles
2.1 Incremental Encoder
The key idea of an incremental encoder is to record relative changes — starting from a reference point (e.g., power-up or zero reset), it measures how much the shaft rotates or moves, rather than directly reporting the absolute position.
- Structure:A coded disc (with transparent/opaque segments), a light source and detector, and a signal output module.
- Signal Output:Usually two output channels (A and B) generate phase-shifted pulses for direction detection, and sometimes a Z-channel provides one reference pulse per revolution.
- How It Works:As the shaft rotates, the optical sensor detects alternating light and dark areas on the disc, generating pulse signals. By counting these pulses, the control system calculates displacement or rotation.
- Limitation:When powered off or without a known reference, the encoder cannot “remember” its position — it must be re-zeroed upon restart.
- Analogy:Imagine drawing tick marks on paper — if you stop halfway and forget where you started, you lose track of your exact position.
- Typical Use Cases: ✔️Monitoring speed or relative movement. ✔️Systems that can perform homing or zero calibration upon startup. ✔️Cost-sensitive or mechanically simple applications.
2.2 Absolute Encoder
An absolute encoder directly reports the current position of the shaft — no homing, no reference point, and it even retains position after a power loss.
- Principle:Each position (and turn, in multi-turn types) is assigned a unique digital code (binary, Gray code, etc.), meaning the system can instantly read the position at any time — even after power cycling.
- Structure:Optical or magnetic discs with multiple concentric tracks. Each ring corresponds to one bit, and the combination of all tracks provides a unique position code.
- Key Advantages: ✔️No need for recalibration after power loss. ✔️Instant position recovery upon startup.
- Analogy:
- Like a clock — no matter when you look at it, you immediately know the time without needing to “reset” it.
- Typical Use Cases: ✔️Systems requiring position retention after power loss. ✔️Multi-axis synchronization, high-precision positioning, robotics, medical devices, etc. ✔️Environments demanding reliability, efficiency, and minimal maintenance.
3. Key Differences Between Incremental and Absolute Encoders
| Comparison Aspect | Incremental Encoder | Absolute Encoder |
|---|---|---|
| Position Output | Relative (pulse count) | Absolute (unique code) |
| Power Loss Behavior | Loses position, requires re-zero | Retains position, no re-zero needed |
| Signal Type | A/B (and optional Z) pulses | Multi-bit code, serial/parallel output |
| Cost & Complexity | Lower, simpler design | Higher, more complex |
| Startup Behavior | Requires referencing | Instant operation |
| Accuracy & Stability | Depends on pulse count and cumulative error | High precision, no accumulation error |
| Typical Applications | Distance counting, speed feedback | Precision positioning, robotics, recovery systems |
Additional Notes:
- Incremental encoders often include a Z-channel for homing.
- Absolute encoders can be single-turn or multi-turn.
- Incremental encoders can struggle at very high frequencies, while absolute types may face communication delays in some designs.
4. Comparative Advantages
Advantages of Incremental Encoders
- Simple, cost-effective, and widely used in general automation.
- Ideal for monitoring relative movement (speed, distance, frequency).
- Reliable pulse output compatible with most PLCs and controllers.
- Excellent for budget-conscious or straightforward systems.
Advantages of Absolute Encoders
- Retains position data even after power loss.
- Instant startup without homing — saving time and improving efficiency.
- Suited for complex, multi-axis, long-travel, or high-precision systems.
Selection Insight
- Choose Incremental → When only relative movement is needed and manual or automatic homing is acceptable.
- Choose Absolute → When position must be retained, precision is critical, or downtime is costly (e.g., printing lines, agricultural robots, medical analyzers, and simulation equipment).
5.Application Examples
Application 1: Automated Production Lines
In automated production systems, precise motion feedback, synchronized speed, and multi-axis coordination are essential.
- For motor speed or conveyor tracking with startup homing → ✅ Incremental Encoder.
- For multi-axis control and precise position recovery after shutdown → ✅ Absolute Encoder.
Application 2: Simulation / Entertainment Equipment
In simulated skiing or interactive systems, mechanical structures often have long travel ranges and frequent reboots.
- For fast recovery, precise position tracking, and safety assurance → ✅ Absolute Encoder.
- For simple distance or speed monitoring → ✅ Incremental Encoder.
6. Why Choose BriterEncoder?
BriterEncoder offers both incremental and absolute encoder families — covering all scenarios from simple motion feedback to advanced absolute positioning.
Our absolute encoder series features:
- 17-bit resolution, multi-turn options,
- 10 mm solid shaft,
- RS-485 Modbus RTU communication,
- IP68 protection for harsh environments.
Our draw-wire displacement sensors provide up to 20 meters of measuring range, and when paired with absolute encoders, they deliver robust long-distance measurement for industrial automation, agriculture, and robotics.
We adhere to the precision philosophy:
“A micron off can waste a mile in production.”
For instance, in a printing collator, even ±0.001 mm deviation can cause material waste — our high-precision encoders prevent that.
Proven across diverse industries — printing, medical, agricultural robotics, and entertainment — BriterEncoder products deliver real-world reliability and measurable value.
7.Selection Guide & Technical Tips
Before selecting your encoder, clarify:
- Do you need position recovery after power loss?
- Is zero-point referencing acceptable at startup?
- Are you measuring movement or absolute position?
General Guidelines:
- If re-homing is acceptable and cost-sensitive → choose an Incremental Encoder.
- If uninterrupted position tracking or multi-axis synchronization is required → choose an Absolute Encoder.
Key Parameters to Consider:
- Resolution / Accuracy: PPR (pulses per revolution) for incremental; bit count (e.g., 12-bit = 4096 codes) for absolute.
- Interface Type: A/B/Z pulse or serial protocols (SSI, RS-485, CAN).
- Environment: Use magnetic or sealed absolute encoders for dusty or oily settings.
- Travel Range: For long-stroke linear or cable sensors, pair with an absolute encoder for optimal reliability.
🤝 Contact Us
If your project involves:
📍 Rotary position measurement
📏 Draw-wire displacement sensing
🎯 Micron-level precision positioning
🔋 Power-loss recovery
🌊 Long travel (up to 20 m)
📡 High-reliability RS-485 Modbus communication
🧱 IP68-grade environmental sealing
We invite you to explore BriterEncoder’s professional encoder solutions.
🌐 Website: www.briterencoder.com
✉️ Email: brt@briterencoder.com
💬 WhatsApp / WeChat: +86 151 8327 6844
Our technical team provides:
✅ Free product selection consulting
✅ Custom measurement solution support
✅ Integration and installation guidance
Empowering your systems to achieve new levels of precision, reliability, and efficiency.
