US Digital Encoder Distance/sec to Rpm

[Lemons]

Ok so this is the first year we have really decided to implement digital encoders on motors. We hooked them up fine and using the example code in LabVIEW were able to get readings. The only question we have is what unit (distance/second) is the encoder reading in and is it possible to change that unit (distance/second) to an RPM reading if its not already set as such? We are using US Digital E4P Quadrature encoders. Thanks

[Team3266Spencer]

Most encoders, and I would assume yours, record the time between two "sprockets" inside the encoder. There are 360 of these bumps inside the encoder so a raw encoder reading will be in degrees. I don't program in LabView, but assuming it's the same speed settings, given with time in seconds, and you want RPMs, you would have to divide by 360 and multiply by 60, or just divide by 6. If you want to calculate distance travelled by a drivetrain lets say, you would need values such as the gear ratios used, and the diameter of the tires, etc.

[blackflame2996]

Actually, the number of pulses per revolution varies. On the casing of the E4P, 3 digits in the number are the pulses/revolution, ranging from 100 to 360. The bore will also be on there, so don't let that throw you off. for example:

http://ivan.blogs.chimerical.com.au/..._36_resize.jpg

The Pulses/Revolution on this encoder is 300, and the Bore is .157 inches.

[Ether]

Originally Posted by blackflame2996

Actually, the number of pulses per revolution varies. On the casing of the E4P, 3 digits in the number are the pulses/revolution, ranging from 100 to 360

That number is Cycles Per Revolution, not Pulses Per Revolution. Those terms mean different things.

[blackflame2996]

You are correct. My bad.