Counter RIO vs. SystemCore Back to Back

[gerth2]

Just a quick update - I ran some testing where I plugged in a Greyhill 63R128 into a SmartIO port, as well as a RIO's digital input. I tied grounds together, and let the SystemCore drive 3.3v for power to the device. I added a 4.7k pullup to signal to get the high value in the range where both devices read it nicely.

I set up the RIO to publish the count to NT on the SystemCore (RIO acted as client).

I was able to spin the encoder by hand at different rates and saw the counts from both devices stay pretty much in lockstep (per screenshot, delta of 1 eventually, after 25k+ counts). Since I was spinning by hand we didn't actuate the full frequency range, but I was able to get up to ~5kHz by spinning it hard enough.

Good results IMO at least on raw count.

[bhjelstrom]

Awesome, and thanks for all of the thorough testing.

[gerth2]

Quick followup - velocity is pretty good too.

Velocity calculation methodology:

    public void update(){

        int curCount = udc.getCount();
        double curTime = Timer.getFPGATimestamp();

        double deltaTime = curTime - prevTime;
        double deltaCount = curCount - prevCount;
        double rate = deltaCount / deltaTime; // Counts per second
        SmartDashboard.putNumber("EncoderTest/SystemCoreCount", curCount);
        SmartDashboard.putNumber("EncoderTest/SystemCoreRate", rate);

        prevCount = curCount;
        prevTime = curTime;
    }