Shaft/Slide Position Encoders

• Quadrature Encoders
• Grey Code / Single Track
• Using Stepper Motors as Encoders

Potentiometers (variable resistors) are probably the most common and cheap position encoder; commonly used in RC Servos. The resistor is connected between power and ground, and the wiper then produces a voltage related to the position. Advantages: Cheap, fast, small. Disadvantages: Low accuracy, short life, intermittant operation (especially when grit, grime, or wear damages the resistive surface).

Suppliers

• http://www.usdigital.com they have encoders up to 2048 counts/rev (8192 in X4 mode), plastic case or heavy-duty IP64 aluminum case.
• http://www.stegmann.com
• http://www.motioncontrol.com
• http://www.positek.com/

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