Encoders and Counters

[DavidGitz]

How many counters does an encoder use (when using at 4x)? From looking at the open.vi for the Encoder a 1x and a 2x uses 1 counter, but for the 4x it uses a "Encoder Ref Open" and the next layer is locked out. I assume using it as a 4x would use 2 counters each, is this wrong?

[jross]

The following thread has a lot more details on how the different decoding types work. http://forums.usfirst.org/showthread...hlight=encoder The help page for encoders specifies that there are 4 for 4x and 8 for 1 or 2x.

[DavidGitz]

hmm, so are these special counters? Because according to the counter documentation we can only use 8 counters at any given time.

[Joe Hershberger]

hmm, so are these special counters? Because according to the counter documentation we can only use 8 counters at any given time.

That's correct. There are 8 general purpose counters (which can do 1x and 2x decoding) and 4 dedicated 4x decoding counters. There are 12 counters total.

[jmittelman]

so if you used the 4x counters for an encoder on each wheel, you would only have 4 2x counters left for other purposes?

[Joe Hershberger]

so if you used the 4x counters for an encoder on each wheel, you would only have 4 2x counters left for other purposes?

No. There are 4 counters that can only decode at 4x. There are another 8 general purpose counters that can decode at 1x and 2x among many other types of measurements. You could decode 12 quadrature signals simultaneously. 4 of them at 4x and 8 at 1x or 2x.

The general purpose counters' modes can be configured independently of one another. You could have 3 counters reading ultrasonic sensors, 2 reading direction sensitive gear tooth sensors, 2 reading continuous-turn pots by routing from the analog triggers, and one decoding quadrature signal at 2x. Etc.

If you choose 4x decoding, you are using dedicated hardware and general purpose counters are unused and unaffected.