Engineering+measurements

Engineering+measurements - Engineering measurements...

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Engineering measurements
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Measurement devices Caliper/micrometer Rotary/linear encoder Hall effect sensor Capacitance probe •L V D T Displacement measuring interferometer •V i b r o m e t e r Accelerometer Strain gage Thermocouple •C M M •S W L I E M •A F M
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Caliper A caliper is a device used to measure the distance between two opposing sides of an object. The opposing sides can be internal or external surfaces of an object. Digital caliper Dial caliper
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Micrometer A micrometer is a device incorporating a calibrated screw used for accurate measurement of small dimensions. Outside micrometer Inside micrometer Depth micrometer
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Rotary encoder A rotary encoder , also called a shaft encoder , measures the angular position of a shaft. Rotary encoders are used in many applications that require accurate knowledge of the angle of a shaft with unlimited rotation, such as industrial controls (positioning tables on machine tools), robotics, a computer mouse, and rotating radar platforms. There are two main types: absolute and incremental (relative). An absolute encoder produces a unique digital code for each distinct angle of the shaft. The optical encoder's disc is made of glass or plastic with transparent and opaque areas. A light source and photo detector array reads the optical pattern that results from the disc's position at any one time. This code can be read by a controlling device to determine the absolute angle of the shaft. 123 2 3 = 8 http://www.youtube.com/watch?v=cn83jR2mchw
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Rotary encoder An incremental rotary encoder , also known as a quadrature encoder or relative rotary encoder, has two outputs called quadrature outputs. Incremental encoders can only determine the change in the angle from an arbitrary starting position. There can also be an optional third output: a once-per-revolution reference. This can be used as an absolute reference, which is required in positioning systems. 0 1 0 1 00 01 11 10 00 http://www.youtube.com/watch?v=yVdNI5VnBZU&feature=related
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Rotary encoder Simple rotary encoder: Mount the disk on the shaft and align between the two “columns”. One side has a light source and the other has a detector. You can determine the change in angle by the bright-dark transitions.
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Linear encoder A linear encoder is a sensor (or read head) paired with a scale. The sensor reads the scale in order to determine position. The encoder can be either incremental or absolute. Incremental linear encoder Read head Scale Optical linear encoder
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Hall effect sensor A Hall effect sensor is a transducer that varies its output voltage in response to changes in magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing applications.
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This note was uploaded on 09/06/2011 for the course EML 2920 taught by Professor Carrol during the Spring '09 term at University of Florida.

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Engineering+measurements - Engineering measurements...

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