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  #16   Spotlight this post!  
Unread 23-03-2014, 10:29
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Al Skierkiewicz Al Skierkiewicz is offline
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Re: cRIO cutting out 5 s after collision

When you see a 5 second gap after a hard collision, expect that the radio power supply was interupted. Not long enough for a complete reboot but certainly long enough for the radio to make a recovery mode and reestablish comms with cRio and field. Just enough will corrupt some of the data. With the 2Can in the loop, check to see how long it takes for the 2Can to recover from a power fault. That is more likely the issue. You moved the comms link so you likely moved the power as well. This is just an accident waiting to happen again. Check this when you can.
I recommend against hot glue for two reasons. If you have applied it correctly, you might not be able to change something if it has failed. That might forever damage the device. If it does pull apart easily, then the hot glue was not applied correctly in the first place and you are only fooling yourself that you fixed the issue. Just because you think you see adhesive applied in an industrial device, do not think it was meant to come apart. The manufacturer might just think the part is expendable.
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  #17   Spotlight this post!  
Unread 23-03-2014, 13:34
MrRoboSteve MrRoboSteve is offline
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Re: cRIO cutting out 5 s after collision

Any chance your radio connector has a custom cable? I've seen teams use the wrong barrel connector and see intermittent issues on the radio.

I've worked with enough teams with random issues caused by continuous* 100% CPU usage to know that pretty much anything can happen. The DS Log Viewer makes this obvious.

* I'm distinguishing "continuous" here from occasional 100% CPU usage, for example when complex imaging logic is running.
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  #18   Spotlight this post!  
Unread 23-03-2014, 14:36
kmusa kmusa is offline
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Re: cRIO cutting out 5 s after collision

Quote:
Originally Posted by Ian Curtis View Post
Not sure if it was one of these or the combination, but it stopped happening!
Great to hear!

We just spent 2 days at Buckeye tracking down Jag-related issues, which ultimately turned out to be a loose wire in a power feed to one of them. (We have the black ones on our robot.)

While we've used the additional features of the Jags to great benefit in the past, the fact that any one of a number of issues can shut down the entire string is problematic (and explains why a number of teams won't use them.)

There are CAN repeaters that would isolate the segments, but they seem pretty pricey for FRC applications.
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  #19   Spotlight this post!  
Unread 23-03-2014, 14:50
RufflesRidge RufflesRidge is offline
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Re: cRIO cutting out 5 s after collision

Quote:
Originally Posted by kmusa View Post
We just spent 2 days at Buckeye tracking down Jag-related issues, which ultimately turned out to be a loose wire in a power feed to one of them. (We have the black ones on our robot.)

There are CAN repeaters that would isolate the segments, but they seem pretty pricey for FRC applications.
In the particular circumstance you are describing, the issue was likely a result of talking to a jag that was (at least temporarily) not there. Which means that a star configuration would have the same issue.

The CAN signal will pass right through an un-powered Jag, they use a short tap on the bus internally, it is not passed through a chip on the board.

The other possibility is that your power issue was on the Jag doing the RS232->CAN bridging which does require powered circuitry.
  #20   Spotlight this post!  
Unread 23-03-2014, 15:26
kmusa kmusa is offline
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Re: cRIO cutting out 5 s after collision

Quote:
Originally Posted by RufflesRidge View Post
In the particular circumstance you are describing, the issue was likely a result of talking to a jag that was (at least temporarily) not there. Which means that a star configuration would have the same issue.

The CAN signal will pass right through an un-powered Jag, they use a short tap on the bus internally, it is not passed through a chip on the board.

The other possibility is that your power issue was on the Jag doing the RS232->CAN bridging which does require powered circuitry.
Thanks for the clarification, especially WRT how the bus is connected internally.

We are using the RS232-CAN bridge capability, I'll have to verify that the Jag in question was performing that function.

-Karlis
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