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Unread 09-03-2009, 11:54
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Pat Fairbank Pat Fairbank is offline
Circuit Breaker
FRC #0254 (The Cheesy Poofs)
Team Role: Engineer
 
Join Date: Mar 2003
Rookie Year: 2001
Location: San Jose, CA
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Re: 2009 Finger Lakes Regional!!!!

Quote:
Originally Posted by esquared View Post
1503's Robot Signal light would go fully out, then blink fast, then come solid again. Once they began to try driving again, the RSL would go out, blink fast, then solid again over a period of roughly 30-45 seconds. While they were located at what was eventually found to be a faulty console location, the robot symptoms they experienced are not possible if the robot was being E-Stopped intermittently. If that was occurring, their RSL would be solid, then go to a slow blink, then solid. If it was an intermittent radio communication issue, the RSL would have gone into a fast-blink mode if the bridge lost contact, then come back solid once regained. I spoke with 1503 immediately following that match, and their drivers agreed that the RSL was doing precisely as I explained above. We then powered up their robot, and showed them the process the RSL light goes through after a reboot. While the robot was on, I showed them what would happen if the radio modem power/ethernet was pulled loose/plugged back in, and the process was also as described above. They seemed satisfied that the symptoms of their robot out on the field matched a poweroff/poweron rather than an E-Stop.

To the robot, the E-Stop button is a disable/enable condition no different than using the dongle normally attached to the competition port. This was evident from the match in finals where the faulty E-Stop was diagnosed. Team 188's robot would sit with their RSL light slowly blinking. This indicates a successful link with the Driver Station, either through the field or when tethered. If the E-Stop was rapidly toggled/intermittent, 1503's robot would have been going in/out of enable mode, thus the RSL would be solid/slow blinking.

I regret not having the chance to follow up with 1503 to determine exactly what their situation was once they were in the pits. If anyone from 1503 could contact me/post if you found anything specifically wrong with your robot following that finals match it would be appreciated. I can add your situation to a list of common robot 'gotchas' being compiled.
I'm afraid we found nothing. We checked every terminal and every wire from the battery all the way to the cRIO. We then tethered up and drove the robot around (with the same battery); it worked fine. We rammed it repeatedly into a wall to see if there were any loose connections to dislodge; nothing. We always run electrical checks between matches, and we always zip-tie our battery connectors, and we didn't experience a single electrical problem at FLR up to that point. I guess I don't believe in coincidences...
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Patrick Fairbank
Team 254 | Mentor (2012-)
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Last edited by Pat Fairbank : 09-03-2009 at 11:56.