System Watchdog - can it be a show stopper?

[Baldini]

I'm  a mentor for Team484 - My question is simple, if the system watchdog timer is not serviced due to temporary loss of wireless network connection, will the PWM and actuator ouputs be disabled?

This would seem to be a show stopper if that temporary loss occurs at the very start of the race.  His there a way to recover once communication as been re-established?

If there is not a way to recover, can the servicing of this system watchdog time be changed to allow some time for the wireless communication to be reconnected?

This problem as been I belive seen by many groups.  Would love to see a direct answer to these questions from the people at NI

Look forward to the answer.

[MarkBlack]

Yes, if there is a lost of network communication at the beginning (or any part) of the match the system watchdog will not be fed and all motors and actuators will be shut off.  The system watchdog will immediately become enabled when communication is reestablished and motors and actuators will begin working.  The system watchdog behaves this way to protect against run-away robots.

Let me know if this addresses your questions completely?

Cheers,

Mark

NI FIRST Support

[Baldini]

Hey Mark,

Thank you for the reply, if the answer is correct then we should not of seen our system PWM die at the start of the game.

Would you be able to input on what could cause the PWM lines to the jaguar controllers to not work, yet two relay outputs which we have connected to 2 additional motors were working just fine.

What could cause the PWM signals to stop or possible the Jaguars to not drive our motors at the start of the game.  When we took the robot back to pit all the problems went away, we also tried using our own router to test the wireless communication and everything once again worked just fine.

My follow up questions would be.

What could cause all my PWM fed motors to not work? keep in mind they did not fail, they just did not work at the beggining of two game starts.

Also keep in mind we ran the previous day just fine.

Look forward to some feedback

[Baldini]

Looking for a reply to my previous reply.

[nathand]

Out of curiousity (no promises that I can provide useful advice here), did this happen to you in all your matches or just two?  Were there any unusual conditions for those two starts (a restart or delayed start due to technical issues, or not having rebooted the robot just before the match)?  Does your autonomous mode use all of the motors (the jaguar ones and the relay-powered ones), or just the jaguar-powered motors?  Did you notice whether your Robot Signal Light was solid or flashing, and if flashing, in which pattern?