Problem reading Quad Encoder, possible Cortex issue Response

[Cyber_brains]

I have a Cortex that is not reading quadrature shaft encoders. The other day a student was complaining that the quad encoder would work, then suddenly stop working. Power cycling the Cortex would fix it temporarily, then it would fail again. Eventually (same day) it stopped working altogether. We tried different ports without success. I attached a second quad encoder to the same shaft and it worked. The next day it worked for a while, then started failing just as the first one did. Eventually (same day), that one too stopped working. I’ve tried different codes (known working code) and different ports, and neither quad works. I’ve moved the quads to another robot and verified that they work fine. It definitely seems as though the first Cortex just doesn’t want to read a quad. I’ve updated the firmware with no change. To be clear, every other sensor installed seems to be working fine.

The other symptoms include the area of the Cortex closest to the LED’s is very hot. Much hotter than other Cortexes and much hotter than I am comfortable seeing it run. Also, rather than flashing two green lights, it flashes yellow.

What is your suggestion?

I have made a new post because I could not post on your original thread>

We had a problem that sounds very similar to yours. Is the encoder directly driven from your flywheels?

Take a look at this.

[ATTACH]9769[/ATTACH]
[ATTACH]9770[/ATTACH]

We broke a Quad before we found this information. By forcing the encoder to spin faster than 1,133 RPM, it starts reading things wrong and can often break the sensor.
Maybe try gearing out from the wheel to the encoder using a torque ratio. Small chain and sprockets would be perfect for this.

Hope this helps.

Let me know if you are still having issues. (you will almost surely have to replace the quad encoder with a new one if this is the problem.)

[OverlyOptimisticProg]

You may want to use a the debugging tool and a code that looks like this:
#pragma(sensor)
int sensorVar=0;
Task main(){
While(true){
SensorVar=SensorValue[sensor];
}
}
Just spin the encoder and see what the value of sensorVar is… I don’t know what is wrong with an overheating cortex but an led will sometimes turn yello when the battery or backup battery is low battery or a bad battery

[EvolvingJon]

We broke a Quad before we found this information. By forcing the encoder to spin faster than 1,133 RPM, it starts reading things wrong and can often break the sensor.

I think many encoders have been sacrificed for science this season for this precise reason, may they rest in peace, or in a junkyard or something. :p.