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Unread 07-02-2005, 09:10
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Re: Problems with PID- PLEASE HELP!!!

Quote:
Originally Posted by thinkpad
I am sorry i don't understand what you meant by going to an encoder with a lower CPR. Do you recommend we get any other encoder in place of the Grayhill 63R128 ?
Exactly. If your pulse per rev is too high, you need an encoder with a lower pulse rate (for example, a Grayhill 61K64 which has half the pulse rate), or you need to set a speed limit. Our team's test bot is doing the latter at the moment, since one of our 64 pulse encoders is broken and we had to sub in 128 pulse encoders, which trigger interrupts a bit too quickly for the controller to keep up.

(As a note, make sure you have a spare, as the Grayhill encoders aren't the most robust encoders out there, a bad blow to the shaft can take one out, and from experience, having to re-write the code in the pits to limp along without an encoder is not fun)