Thread: EP4 frequency
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Unread 19-07-2012, 10:51
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Re: EP4 frequency

Quote:
Originally Posted by ryanm222 View Post
Hi,
I am new to this site and new to encoders so bear with me. I am using the EP4-100-079-D-H-T-B single-ended encoder on a 200 RPM motor, and I am not getting the frequencies I expected. I hook one of the output channels to an oscilloscope and get a clear square wave except the frequency is about 1.5 kHz when I am running the motor at about 20 RPM when I excepted the frequency to be about 33 Hz. The encoder is hooked up to a 5V supply as specified. Am I getting the correct output or is something causing the frequency to be high? If that is the excepted frequency for 20 RPM, why is so much more than I excepted? Thank you for any help.

Ryan
Welcome!

Most encoders don't create one pulse per revolution, but rather offer a pulse every portion of a revolution, sometimes 128 or 256. This is referred to as Pulses Per Revolution (PPR). Another unit used is the CPR, or Cycles Per Revolution - almost always four pulses.

That's why you're seeing so many Hz. Just divide it by your encoder's PPR to get the encoder disc's RPS (Revolutions Per Second). You can then obviously multiply it by 60 to get the RPM.

The E4P encoder comes with PPRs between 400 and 1400, and CPRs between 100 and 360. I don't know your particular model's spec.
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