Incremental Encoders Explained: How They Work and What to Know Before Buying

In the world of motion control and industrial automation, incremental encoders are the go-to solution for tracking rotational or linear movement with high precision. These compact, reliable devices are found in everything from CNC machines to robotic arms.

In this post, we'll dive into:

• How incremental encoders work

• Key technical characteristics

• Where they're used

  
  

🔍 What Is an Incremental Encoder?

An incremental encoder is an electro-mechanical device that converts motion — typically rotation — into digital pulses. These pulses can be used to track position, speed, and direction.

⚙️ Operating Principle: How Incremental Encoders Work

Inside every incremental encoder is a rotary disk with regularly spaced slots or markings. Here's what happens:

1. The encoder shaft rotates.

2. A light source (usually LED) shines through or reflects off the disk.

3. Sensors detect the interruptions in light (or magnetic field, in some models).

4. The output is a stream of digital pulses — one pulse per slot.

Each pulse corresponds to a fixed increment of rotation (e.g., 1°, 0.1°), hence the name incremental.

🧠 Direction Sensing

Most encoders have 2 channels (A & B) offset by 90°, allowing the detection of rotation direction through quadrature encoding.

📐 Technical Characteristics to Know

Parameter	Description
Pulses per Revolution (PPR)	Number of digital pulses generated per full rotation of the shaft.
Output Type	TTL, HTL, Open Collector, Push-Pull
Shaft Type	Solid shaft or hollow shaft
Power Supply	Typically 5V, 12V, or 24V
Mounting	Flange, servo mount, or through-bore
Ingress Protection	IP ratings for dust/water resistance
Connector Type	Cable or M12 connector

🏭 Applications of Incremental Encoders

• 🛠️ CNC Machines: Position tracking of motors and axes

• 🤖 Robotics: Joint and wheel feedback

• 🏗️ Industrial Conveyors: Speed and distance monitoring

• 🌀 Servo Motors: Real-time motion feedback

• 🎥 Camera Sliders / 3D Printers: Accurate movement control

  
  

🛒 Best Incremental Encoders

🔧 1. AUTONICS E40S6-1000-3-T-24

• 1000 PPR, NPN Open Collector Output

• Great for medium-precision control systems

• 🔗 Buy on Amazon 

  
  

🔧 2. Rattmmotor 400PPR Incremental Encoder

• Compact, budget-friendly

• Comes with a DC 5–24V range and TTL output

• 🔗 Buy on Amazon

  
  

🔧 3. Sainsmart Optical Rotary Encoder

• 600 PPR, 2-channel TTL output

• Ideal for Arduino, Raspberry Pi, or prototyping projects

• Buy on Amazon 

  
  

📘 Buying Guide: What to Consider

Feature	What to Look For
PPR	Higher = more resolution. Typical range: 100–5000.
Shaft Size	Match motor shaft or mounting hub
Output Signal	TTL is common, choose based on controller support
Mounting	Verify physical space and fixture compatibility
Application	Harsh environment? Choose encoders with IP65+ rating

⚖️ Incremental vs Absolute Encoders

Feature	Incremental Encoder	Absolute Encoder
Power-Loss Recovery	❌ Needs homing	✅ Keeps position
Complexity	✅ Simple	❌ More complex
Cost	✅ Lower	❌ Higher
Use Case	Real-time movement	Precise positioning

🧠 Engineering Calculations for Incremental Encoders

Incremental encoders don’t provide absolute position directly — they provide pulse counts that you use to calculate position, speed, or direction. Here's how:

1. 🔄 Angular Resolution Calculation

This tells you how much angle (in degrees) each pulse represents:

🧮 Formula:

🔧 Example:

For a 1000 PPR encoder:

2. 🚀 Rotational Speed (RPM) Calculation

If you count how many pulses are generated in a fixed time, you can calculate RPM:

🧮 Formula:

🔧 Example:

• 1000 pulses counted in 1 second

• Encoder is 500 PPR

  
  

3. 📏 Linear Distance Calculation (for linear motion encoders)

If the encoder is coupled to a wheel or belt, you can convert pulses to linear distance:

🧮 Formula:

Where:

• Circumference = π × diameter of pulley or wheel

  
  

🔧 Example:

• Wheel diameter = 100 mm → Circumference ≈ 314 mm

• Encoder PPR = 500

• 250 pulses detected

  
  

4. 🧭 Direction Detection (Using Quadrature Encoding)

• Channel A and Channel B are 90° out of phase.

• If A leads B, the shaft is rotating clockwise.

• If B leads A, it's counterclockwise.

  
  

This is handled by logic circuits or microcontrollers.

🔚 Final Thoughts

Incremental encoders are vital for motion tracking, and selecting the right one depends on your application’s precision, output type, and mechanical fit. With a wide variety available even on Amazon, getting started is easier than ever — whether you're upgrading your factory floor or building a new robotics project.

👉 Explore the recommended models above and make sure to choose the encoder that fits your specs and budget.Incremental Encoders Explained: How They Work and What to Know Before Buying