Unidentified Problem
 

Team 3397 has been prepping our robot for a club fair, but when the time came for us to present our robot, we could not drive it. During our meeting, we have broken down the problem and we were wondering if CD could help us identify it.

• Our signal light will not turn on, even if the robot is enabled
• Our robot will not drive
• We are getting communication from the bridge to the cRio, and are able to ping it
• We tried switching to an alternate digital sidecar, signal light, modules, and the cable connecting the cRio to the digital sidecar
• Our motor controllers are not getting a signal
• Everything is getting power, we are not sure about the light

If you can help us identify the problem and help us fix it, it would be much appreciated.

Thank You.

Re: Unidentified Problem
 

Lots of potential causes.

What do the other statuses show?

• On the cRIO
  • The cRIO power light (by the power plug)
  • The cRIO status light (below the power light)
• Digital Sidecar
  • The tiny RSL LED directly on the Digital Sidecar (by the power plug)
  • The three power lights all bright green?
• The status lights on the speed controllers are blinking I take it?
• The other Driver Station Diagnostic indicators
  • Communication
  • Robot Code
  • Other Diagnostics, e.g., cRIO?

You said you were able to Enable the robot, and that'd only be possible if the cRIO were running normally. If that's true then

• Digital module in slot 4?

• You can try pulling the breaker for the digital sidecar to see if the 5v light glows but the others go out. That'd mean the Sidecar was getting power through the 37-pin cable.

Re: Unidentified Problem
 

Are you using Victors or Jaguars? We had the same problem this year prepping for an off season event. Our Victors had been unplugged and cleaned up and we found out that if you plug the PWM cable back in it doesn't always connect. Not sure if that happens on a jag or not, we had a tally on our jaguar stickers very much like the red baron and after the sixth on started on fire we ditched them and haven't looked back.

But check and double check the connection between the PWM cable from the sidecar and the speed controller. Once we had that in everything came back to life and all was good.

Re: Unidentified Problem
 

In this vein, you can test the PWM connection using a servo (and a servo PWM jumper), just to see if the PWM is issuing a signal.

Re: Unidentified Problem
 

Just to make sure, did you remove the encryption from your event last year?

Re: Unidentified Problem
 

are you using PWM or CAN? if PWM< jaguars or victors? if CAN, 2can or serial?

any recent code changes/re-writes? What language?

also make sure all of the wiring to the motors is good (no criss-crossed motor wires).

Re: Unidentified Problem
 

The problem turned out to be the digital module in the wrong slot, so thank you Mark for pointing out what we missed.

Thanks for the help everyone! :D