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Unread 16-03-2012, 23:39
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RyanN
AKA: Ryan Nazaretian
FRC #4901 (Garnet Squadron)
Team Role: Mentor
 
Join Date: Jun 2006
Rookie Year: 2005
Location: Columbia, SC
Posts: 1,126
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Re: Team Fusion #364, Bayou Regional, FMS Woes

Quote:
Originally Posted by Mr. Lim View Post
I know this is probably obvious, but is there any chance your radio is in Auto or AP mode?

Is your radio mounted near motors, and anything else that could cause interference?

Is it buried deep within the robot, possibly shielded from the wireless signal?
Our radio is connected below our shooter motors, but we're losing connection while disabled as well, so this is not caused by EMF.

Quote:
Originally Posted by Chinmay View Post
Dear Ryan

First off, I'm really sorry to hear that you and your team had so many difficulties this week at the regional. I sincerely hope that you can have a strong showing in your last match and get the chance to compete in the eliminations.

I would love to hear more about the technical problems you experienced, and hopefully offer a solution. I know you may have already tried what I will suggest below, but I hope you can check this message before tomorrow and that something in my post may solve your problems.

We had this issue last year at chesapeake regional, and it was ultimately fixed by turning off the wireless on our classmate pc. (Wireless has been off.)We had intermittent connectivity, much like what you are describing, and then when the wireless was turned off, the robot worked fine. Our symptoms were much like yours, bad connection, and losing coms for almost the entire match. That may be a quick fix if you haven't tried it, although I'm sure you guys have gone through the motions and thoroughly checked everything, and it seems like your router is staying connected, but I wanted to throw this out there. It took us a whole day of trying to work this out last year!

Today, at NYC regional, we had a similar problem which we now have solved. To begin with, I'll describe the problem. We would have coms (albeit after much longer than it normally takes to connect to the field) and then promptly lose communication as soon as we began to drive our robot in tele-op. We were not doing anything fancy that would drop our voltage low enough to reboot the crio ( which would result in about a 45s delay) and we would get erratic times for the loss of communication ranging from 15 seconds, to longer than a minute. This suggested that the problem wasn't something to do with the crio rebooting. We did notice that we were dropping packets.

The FTA, after we spent the day trying different things, and swapping out components, suggested we replace all the wiring to/from the wireless bridge, in our case, specifically an ethernet cable from the bridge to the 2Can. I believe doing this solved our problem, I guess we'll see for sure tomorrow if it worked, but we were finally able to connect successfully. Like you guys, both years we were perfectly fine running tethered.

Here's what we have replaced:
  • cRIO
  • Digital Sidecar
  • Dlink Router
  • Dlink Power Cable
  • Ethernet Cables

I would strongly guess that the problem was a connection, but we're losing communication while disabled and everything. We can run wireless in the practice field and it runs perfectly.


Let me know if this works for you tomorrow. I can type up a more detailed report, including specifics on what we experienced if you send me a PM.

Once again, I'm really sorry to hear that the communications issues caused you guys to not be able to show what your robot can really do. Best of luck!
I will update tomorrow after our match if we run or not. I have a bad feeling that it has been the code the entire time. No reason the code is failing, just that it's too complicated for the FMS to handle for some dumb reason. I know it doesn't make sense, but there's nothing else I can think off as to why it works great everywhere except the field.
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Garnet Squadron
FRC 4901
Controls Mentor
@rnazaretian

Previous mentor and student from Team Fusion, FRC 364