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Unread 14-04-2012, 21:58
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Re: Encoders on Drive Train DON'T WORK.

Quote:
Originally Posted by JamesTerm View Post
http://www.usdigital.com/first

This link shows 166 rps...

For the E4P, the maximum output frequency is 60 kHz (60,000 cycles per second). A 360 CPR encoder produces 360 pulses on each channel per revolution. To solve for how fast the encoder's shaft must turn per second to reach the maximum output frequency, divide the maximum frequency by the pulses per revolution. 60,000 / 360 = 166 revolutions per second. To convert to RPM multiply by 60 (10,000 RPM).
That's an encoder limit. I'm talking about the FPGA.

This is from WPILib Encoder class:

Code:
/**
 * Common initialization code for Encoders.
 * This code allocates resources for Encoders and is common to all constructors.
 * @param reverseDirection If true, counts down instead of up (this is all relative)
 * @param encodingType either k1X, k2X, or k4X to indicate 1X, 2X or 4X decoding. If 4X is
 * selected, then an encoder FPGA object is used and the returned counts will be 4x the encoder
 * spec'd value since all rising and falling edges are counted. If 1X or 2X are selected then
 * a counter object will be used and the returned value will either exactly match the spec'd count
 * or be double (2x) the spec'd count.
 */