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What is a Quadrature Encoder?
Tags: FAQ I/O Module Feature
Quadrature encoders are used to measure both the speed and direction (clockwise or counter-clockwise) of a device.

Each encoder has two tracks, A and B (thus two inputs are required), that are 90° out of phase, which enable it to provide accurate position information. It will count up when phase A precedes, and count down when phase B precedes. The length of travel can be determined by the speed of the incoming pulses.

In MAPware-7000 Quadrature 1X mode, the current value increments or decrements at the rising or falling edge of the phase B input after the phase A input has turned on.



Quadrature 2X Mode works the same as 1X Mode, except that the current value also increments or decrements at the rising or falling edge of the phase B input after the phase A input has turned on or off, doubling the number of pulses counted per revolution.



In Quadrature 4X Mode, the current value increments or decrements at the rising or falling edges of the phase A and B inputs. Both rising and falling edges of each phase are counted. This essentially quadruples the number of pulses per revolution, by counting 4 times the pulse frequency.



Please see Tech Note 7010 "High Speed Counters and Encoders" for more information.
Content Created by David Franzwa