Thread: Match Communication Problems
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Unread 10-03-2010, 09:48
Jack Jones Jack Jones is offline
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Location: Waterford, MI
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Re: Match Communication Problems
Been there, done that last year when we would die in about 1/4 of our matches.

It's such a shame that such a beautiful wiring job as yours would have those kinds of problems. But the cold hard fact to face is that we have a labortory instrument (cRio) talking to a desk-top gaming adapter riding on a 150# robot @ 10fps, when neither of which was intended for that application.

But it is what it is - so here are the things to look for - and don't stop just because you find something, there may be multiple glitches.

#1: Cat connections at cRio and bridge. Get a good connection and hot-glue - use a Cat-5 AB switch for teathering.
#2: Power to the CRio and bridge - both are lame for this application - hot-glue the bridge connection, or hardwire it (if rules allow that?)
#3: Main Breaker - have heard of them tripping without opening the lever, and without excess current. cRio has no battery back-up and will want to re-boot when power is interupted - even for an instant.
#4: DB37 cable to d-side car - make sure it's screwed in at both ends.
#5: Your code - I know you use Lab View, but have you written a custom vi? Check your memory allocation. If you access a pointer without having allocated memory {eg. pntr = new Thimajig(1,2);} you will get a "watchdog not fed" error and die when you try to read or write to that address. I observed that you don't die till teleop, and then not at any particular time during that period, except maybe when kicking. Look for something you don't do in auto-mode that you do in tele, with special attention to your fire control.
#6: Something I've seen in common with bots having dropped com issues is that either the cRio or camera is mounted on a large sheet of polycarb. The NI rep postulates that the polycarb can build up a surface charge. Since the polycarb is usually attached to the isolated frame, the only way to discharge is thru the cRio or camera frames, which are grounded. Neither the cRio nor bridge will tolerate spikes!!!

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