Since we have gone this far, it sounds like the FPGA and 9403 I/O card are cponservatively capable of say 5000+ rpm per quadrature encoder. Hopefully the encoder and the Digital side car D/I electronics & the cable to the CRio bandwidth are also rated for those rates. Note a grayhill 61R256 encoder is only rated for 300 RPM.
A quad encoder takes 2 of the 14 DI ports so does that mean the system could handle 7 quad encoders each running at 5000 rpm ? (or is there a limit in wpilib but not in the CRio / fpga for example).
It also sounds that if you are not using quadrature encoding (ie only single rising edge detection) and only using a single DI port (ie don't need to know the rotation direction), 14 channels of 10,000 RPM (at 256 rising edges per revolution: or 2,560,000 rpm at a single rising edge per revolution (as long as the 6.525 microseconds is maintained ? ) ?
perfect conditions example assuming 6.525 us for up pulse, 6.525 for down, single pulse per rotation, 0 phase error max RPM might appear to be 60 / (2 * 0.000006525) = 4.8M rpm. Sounds like I have something wrong here
Just trying to understand the envelop of capability of the Crio/FPGA product.
Back to building robots and trying to do pid on a 7200 rpm motor.