Low Res Optical Encoders for Speed Control

[Ether]

Originally Posted by KrazyCarl92

We have a 2 axle shooter, so if we had 2 axles reading that fast, could the FPGA handle it? I.E. would that then become 48,000 counts/sec?

I believe each FPGA input channel can handle 40,000 counts/sec. Perhaps someone with intimate knowledge of the FPGA could comment.

Also, are there other variables that could affect the FPGA and how it counts the encoders, and where can I read up to learn more about it?

Download a copy of the WPILib C source code and read the descriptions of the methods in the Encoder and Counter classes.

[AllenGregoryIV]

I know we were having issues with the 360 count encoder on our shooter but that may have just been our setup. We end up moving to a cheap IR reflective sensor and piece of white tape and it's worked perfectly.

[Greg McKaskle]

Not that I'm an expert on the API or anything, but looking at the LV implementation, there are four 4x encoders and eight counters that can be used for 1x and 2x. As stated before, they are running on the FPGA and run in parallel along with each other, PWM generation, triggers, etc. So, the encoders will not be an issue.

Greg McKaskle

[cgmv123]

I think the actual number is 39,230.