Vexing bug (possibly system watchdog related?)

[LyraS]

We have a problem with our robot.

The symptoms are: every 30 seconds, or so, all the motors, servos and solenoids on our robot turn on and off for about 100-500 ms. This happens repeatedly over a 2-3 second interval, after which everything is fine for another 30 seconds - 1 minute (and then the whole sequence repeats).

When this "chatter" occurs, we get "Watchdog not feed" warnings on the driver station.

We get this same problem when using the out-of-the-box SimpleRobot sample code in WindRiver.

It happens with a much simpler program (<50 line and no Watchdog object instantiated at all). The program is attached.

It happens on multiple cRios.

It happens even if we raise our Task Priority to 1.

It happens if we simply set a motor running and then go into a Wait state for 10 minutes.

We've had this problem for quite a while (months) over multiple cRio image version, versions of wpilib, etc.

We are running out of ideas on debugging this. Any help would be greatly appreciated!

Thanks,

Geoff

[imac256]

Does this occur over wireless or tethered operation? If it has only been tested over wireless then try tethering to see if it still persists then. What could be happening is that the network traffic is taking a long time to reach the cRIO and is causing a system Watchdog to take hold temporarily.

-Ian McInerney
Programmer, Team 2022

[LyraS]

Originally Posted by imac256

Does this occur over wireless or tethered operation? If it has only been tested over wireless then try tethering to see if it still persists then. What could be happening is that the network traffic is taking a long time to reach the cRIO and is causing a system Watchdog to take hold temporarily.

-Ian McInerney
Programmer, Team 2022

That's a good idea... I'll try that (I am running wireless).

[LyraS]

That worked like charm! Thanks!

[jalburty]

Now that you have it working in tethered mode. What do you plan to do for wireless?

Does anyone else suspect the router as I do?

[Redneck]

We had the exact same problem. It occurred on both wired and wireless communication. After spending an ungodly amount of time trying to debug it, we finally talked to one of the WPILib guys and he said the problem was likely the camera... apparently that task was preventing the communication task from sending data (hence the watchdog timeouts) and the only fix we had was to completely remove the camera code.

[Merle]

We had a periodic system watchdog issue (approx 4 per minute) that I finally traced down to an issue of the Classmate's power scheme (actually Intel's power saving scheme called SpeedStep). We have been programming with LabView; however, I see this as a Classmate DS/DB issue not a cRIO issue.

We would see it in wireless or tethered modes, and would see the watchdogs typically disappear when the Classmate was powered with the AC adaptor. If you see watchdog errors disappear with AC power I suggest you read more about it in this thread:
http://www.chiefdelphi.com/forums/sh...ad.php?t=84281

Merle Yoder
The GRUNTS Team #3146