The document provides an overview of optical encoders from Grayhill Inc., including how they work, common parameters, and applications. It describes incremental and absolute encoders, as well as human interface, general purpose, special function, and machine interface encoder products. Specific encoder models are detailed along with their typical resolution, features, and suitable applications.

1. Optical Encoders Source: Grayhill Inc

2. Introduction Purpose An overview classification of Grayhill optical encoders Outline Working of optical encoders and parameters Common characteristics of encoders Human interface encoders, features and applications General purpose optical encoders, features and application Special function products, features and applications Machine interface encoders, features and applications Content 20 pages

3. How Optical Encoders Work The photo detectors are special transistors that allow current to flow when the light from the LEDs is shining on them Two LED-photo detector pairs are used, these produce the outputs A and B The alternating on-off state produces the output signal LED Photo Detector Code Rotor LED Photo Detector Code Rotor Output A Output B OUTPUT A OUTPUT A OUTPUT B

4. Incremental / Absolute Encoders Indicates closed circuit, blank indicates open circuit Indicates closed circuit, blank indicates open circuit Incremental Encoder Absolute Encoder Quadrature 2-bit Code ¼ Cycle per Detent Code Position Output A B 1 2 ■ 3 ■ ■ 4 ■ 5 6 ■ 7 ■ ■ 8 ■ 9 10 ■ 11 ■ ■ 12 ■ 13 14 ■ 15 ■ ■ 16 ■ 4-bit Gray Code – 16 Position Code Position Output 1 2 4 8 1 2 ■ 3 ■ ■ 4 ■ 5 ■ ■ 6 ■ ■ ■ 7 ■ ■ 8 ■ 9 ■ ■ 10 ■ ■ ■ 11 ■ ■ ■ ■ 12 ■ ■ ■ 13 ■ ■ 14 ■ ■ ■ 15 ■ ■ 16 ■

5. Optical Encoders Parameters Pulses Per Revolution (PPR): The # of quadrature state changes per 360° rotation of the shaft Cycles Per Revolution (CPR): The number of full quadrature cycles per 360° shaft rotation (four pulses per one cycle) Resolution : The number of Pulses Per Revolution (PPRs) or Cycles Per Revolution (CPRs) in a specific encoder’s output For example: encoders with low PPRs (4-32) are “low resolution encoders” one cycle OUTPUT A OUTPUT A OUTPUT B ONE PULSE ONE PULSE ONE PULSE ONE PULSE POSITION 1 2 3 4 5 7 6

6. Common Characteristics of Encoders Long life 1,000,000 to 300,000,000 cycle reliability, no mechanical contacts Require power source Typically at 5V Can be customized (3.3V, 12V, 18V) Cable and connector options Sealed versions available Customizations available Shaft size / configuration Detent / rotational feel Terminations Bushings Output codes

7. Human Interface Encoders Typical Features of Human Interface Encoders Low Resolution: Specified in Pulses Per Revolution (PPRs) Detents: The place where the shaft “clicks” into position while rotated Pushbutton Feature

8. Human Interface Products Grayhill offers four general purpose optical encoders suitable for human interface applications It includes 61B , 61C, 62A and 62S products The 62S is the latest offering. It is the smallest package size encoder available

9. Human Interface Applications Medical applications: Ultrasound equipment, patient monitoring device Defibrillators, X-ray equipment Automotive applications: Navigation systems climate controls Industrial application: Machine tools, process controls, factory automation Communication equipment, handheld tablets - voting machine, lab instruments, avionics

10. Advantages of Human Interface Encoder Compared to a mouse: An encoder can be mounted on the front panel of the device. This results in a self contained assembly that does not require additional space or surfaces for a mouse pad. Compared to keypads: Optical encoders require less panel space. Operators do not have to look directly at the encoder while scrolling through menus or inputting data. Compared to potentiometers: Optical encoders output digital signals that are more compatible with today’s digital devices vs. the analog output of a potentiometer. Compared to trackballs: Optical encoders allow incorporation of “push to enter” pushbutton functionality. Optical encoders resist collecting dust and are therefore lower maintenance than trackballs.

11. General Purpose Optical Encoders Grayhill offers four general purpose optical encoders suitable for human interface applications It includes 61B 61C, 62A and 62S products The 62S is the latest offering. It is smallest package size encoder

12. Special Function Products Encoders with Joysticks - Series 60A and 60C: The 60A and 60C joystick encoders incorporate an 8-way mechanical joystick The 60C separates the pushbutton and joystick from the encoder on concentric shafts The joystick provides added functionality in a single package Its applications include automotive, avionics, commercial Concentric Shaft Optical Encoders – Series 62C: A concentric shaft encoder with a non-rotating inside shaft Insures against accidental actuation Insures proper orientation of any legends printed on knob

13. Special Function Products High Torque Family: Products with high torque detent systems. Required when application calls for positive tactile feedback. Avionics, pilots desire a positive detent feeling. Any application where an operator is likely to be wearing gloves. These products require two to four times more rotational force to actuate compared to standard encoders.

14. Special Circuitry Low Power - 62V: Operates at lower voltage (3.3V) Ideal for battery operated devices Lower voltage also reduces risk in explosive environments Circuitry-Lighted Shaft-Series 62F : An optical encoder with integrated LED and light pipe Simplifies panel design Redundant Circuits – 62R : Ideal for critical applications Target industries: Avionics Originally designed for a helicopter ground avoidance system 62P Human Interface 16 Detent Positions Introduced as a low price optical encoder to compete against low price mechanical encoders Life: 500,000 cycles

15. Higher Resolution Encoders Grayhill offers three higher resolution encoders suitable for human interface applications Ideal for human interface applications where fine adjustment, greater accuracy and smooth continuous rotational feel is required 61K and 61R encoders have 256 cycle per revolution product Grayhill uses a special chip instead of photo detectors in 61S family in order to achieve the reduced package size

16. Applications of Higher Resolution Encoders Electric welding machines. Medical ventilator Test equipment Audio mixing consoles High end amplifier

17. Machine Interface Encoders Encoder is used as a feedback device in a motion control system. Installed with moving equipment, not turned by hand. High resolution (specified in cycles per revolution). No detents. No push button feature. May incorporate ball bearings to withstand high RPMs and shaft loads

18. Machine Interface Encoders Series 63A: Absolute code output, 20mm package 256 Cycles Per Revolution (CPR), 8-bit code Suitable when application requires discrete position detection at power-up Series 63Q 20mm package 1024 Cycles Per Revolution (CPR). Series 63T Hollow shaft-mounts to end of motor or rotating shafts up to .375” Metric sizes available Up to 1024 Cycles Per Revolution (CPR)

19. Applications of Machine Interface Encoders Motor shafts Conveyor belts Machine tools Robots Factory automation Office printer / copier mechanisms Antennas and telescopes Elevators Printing equipment Smartcard fabricating equipment

20. Additional Resource For ordering Grayhill Optical Encoder, please click the part list or Call our sales hotline For more product information go to http:// www.grayhill.com/opticalencoders/default.aspx Visit Element 14 to post your question www.element-14.com For additional inquires contact our technical service hotline or even use our “Live Technical Chat” online facility