How much PPR do you use on your encoders?

[adciv]

Originally Posted by asid61

EDIT: On topic: The results of the poll are pretty interesting. It looks like most people are using 256 or 512 CPR encoders, with a few people using 64 CPR (or just picked the wrong option in the poll... I should have used CPR instead).

The two common encoders are 250 & 360 from US Digital. Not sure about the (much higher) others.

[asid61]

Originally Posted by Ether

I think you have that backwards.

Yup.
I knew it in my head as I was typing, and it came out all weird. I edited the post to reflect the correct notation.
I had it right in the poll though.

Originally Posted by techhelpbb

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Okay then what exactly is 'cycles per revolution' in that context?

I can see a 100 cycles per revolution encoder yielding 400 pulses per revolution.

I can see a 360 cycles per revolution encoder yielding 1440 pulses per revolution.

Those are all multiples of 4.
I have taken a ton of PCB out of these encoders (they fail a lot and not just in FIRST robots but on my MaxNC CNC tools) and there is no decoding in them.

Are they just being cute and declaring the pulses you could get in the decoder circuit with a 4x decode? Effectively exchanging the meaning of PPR and CPS as other companies use it?

Probably just USDigital being weird. I find that I like their method because it essentially shows the maximum possible precision you can get with an encoder.
If your encoders fail a lot, you may want to consider just switching to magnetic encoders. 115 has killed many, many US Digital encoders in its time.