Encoders Used In Materials And Measurement

Encoders

1. Encoders Name: Balaji Laxman Naik PRN: 23070127016 RA-1

2. Definition An encoder is an electro-mechanical device or digital circuit that converts information from one format to another, usually from motion/position or decimal input into a coded output. In Digital circuits Encoders convert multiple lines into a smaller number of output lines. In Sensors/Automation Encoders convert mechanical motion into an electrical signal 20XX Pitch Deck 2

3. Classification of encoders based on output/Function Absolute Encoders Each position on the encoder has a unique binary code that can be read directly by a controller They retain their position Information, even after power is restored, without need to re-home Provides a digital data stream such as serial synchronous interface Ideal for applications where exact position must be known Simple system design since external counters are not needed More expensive and more complex to manufacture 20XX Pitch Deck 3 Incremental Encoders Generates pulses that correspond to small movements. The external counter sums these pulses to track the total movement and determine position Position information is lost when power is lost, requiring system to know a reference point. Produce a square wave output, typically with A/B quadrature signal to indicate direction. Used in applications where the cost-effectiveness of open loop system is paramount More affordable and provide good resolution for cost Require external hardware and software for position tracking

4. Working Principle Illustrations 20XX Pitch Deck 4

5. Classification by Sensing Technology 20XX Pitch Deck 5 Mechanical Encoder A mechanical Encoder is the earliest and simplest type of encoder It converts mechanical movement into electrical signals using physical contacts, using metallic brushes or contact switches that open/close as shaft/disk moves Optical Encoder It is a type of position sensor that converts mechanical motion into digital signals using light It is the most common encoder type due to its high resolution, accuracy and reliability. Magnetic Encoder It is a position and speed sensor that uses magnetic fields to convert mechanical motion into electrical signals. Works on the principle of sensing the change in a magnetic field as a disk/strip with magnetic poles moves past a magnetic sensor. Often used in harsh environments where optical encoders would fail

6. Mechanical Encoder 20XX Pitch Deck 6 Construction: Rotating Shaft/Disk Conductive and Non Conductive Segments Fixed Brushes/Contacts Output Terminals Working Principle: When the shaft/disk rotates, the conductive segments touch the brushes, completing the circuit outputting 1 When the brushes rest on a non-conductive gap, the circuit is broken outputting 0. Thus, the encoder outputs a sequence of digital pulses as the disk moves.

7. Optical Encoder 20XX Pitch Deck 7 Construction: Light Source Code Disk/Scale Photodetector Signal Processing Circuit Shaft or Linear Mechanism Working Principle: When the shaft moves, the code disk rotates As the disk rotates, the transparent and opaque sections interrupt the LED light beam. The photodetector senses these interruptions and produces ON and OFF signals. These signals are then converted to Pulses-> for incremental encoders Binary Code -> for absolute encoders

8. Magnetic Encoder 20XX Pitch Deck 8 Construction: Magnetized Disk or Strip Magnetic Sensor Hall Effect Sensor Magneto-resistive Sensor Electronics Output Terminals Working Principle: As the shaft or strip moves, the alternating magnetic poles pass by the magnetic sensor The sensor detects the variation in magnetic field Each change corresponds to a pulse (0 or 1) By counting these pulses, the system can measure Speed Direction Position

9. Comparison Summary 20XX Pitch Deck 9 Feature Mechanical Encoder Optical Encoder Magnetic Encoder Sensing Principle Physical contact (Brushes/Wipers over conductive segments). Light interruption/reflection (LED & Photodetector). Magnetic field detection (Hall Effect or MR sensors detecting magnetic poles). Resolution/Accuracy Low (Limited by physical segment size and contact bounce). Very High (Highest precision, best for fine movements). Medium to High (Good, but sensitive to external magnetic noise). Durability/Environment Low (High wear & tear, sensitive to vibration). Medium (Non-contact, but highly sensitive to dust, dirt, and oil blocking the light). Excellent (Non-contact, highly durable against dirt, moisture, and vibration). Speed Handling Limited (Cannot handle high RPM due to mechanical bounce). Very High (Non-contact, excellent for high-speed systems). High (Non-contact, reliable at high speeds). Cost Very Cheap High (especially for high-resolution absolute models). Medium Best Use Simple, low-speed consumer controls (e.g., volume knobs). Precision machinery, Robotics , CNC tool positioning, laboratories. Harsh industrial environments , automotive, electric motors (servo/crankshaft feedback).

10. Advantages & Applications Optical Encoders Advantages Highest accuracy and resolution (detects micrometer movements). Non-contact operation means no mechanical wear and a long lifespan. Works reliably at very high speeds . Digital output is easy to integrate with microcontrollers and PLCs. Applications Precision Robotics (joint angles, wheel rotation). CNC Machines (tool positioning and feedback). Industrial Servo Motors (high-accuracy speed and position control). High-precision medical and laboratory equipment. 20XX Pitch Deck 10 Mechanical Encoders Advantages Very simple and low cost. Easy to implement (no complex sensors needed). Can work without external power for basic contact switching. Applications Simple control knobs (e.g., volume, channel selection). Low-cost consumer appliances (e.g., washing machines, ovens). Low-speed mechanical counters. Magnetic Encoders Advantages Excellent durability in harsh environments (resistant to dust, oil, and vibration). Non-contact operation ensures a long service life. Handles high speeds reliably. Generally lower cost than high-precision optical absolute encoders. Applications Automotive Systems (crankshaft/camshaft sensing, ABS wheel sensors). Electric Motors in industrial settings. Heavy industrial machinery (e.g., steel mills, textile machines). Elevators and escalators.

11. THANK YOU - Balaji Naik 20XX Pitch Deck 11