HELP: Robot randomly loses communication during matches

My team have just participated in Brunswick Eruption 2023. We had two occasions during PlayOffs where our robot lost communication - and it returned after a while. We also had more constant problems during another OffSeason midyear.

We decided to finally look at our DS Logs to understand what’s going on and why is it so random (sometimes it happens after a collision and sometimes its just out of nowhere). I selected two logs during BE where we lost com. I’m anexing them in this post.

Basically we noticed we have brownouts in almost every match, but sometimes - even with insane voltage drop, the robot works smoothly - and again, sometimes it doesn’t. We couldn’t really find a pattern in our logs, so I’m asking for help to make sure the issue is just about battery (and how can we fix it) or if there is something else we need to worry about. (83.8 KB)

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How is your radio wired?

Did you confirm there are no loose connections?

As far as the log shows, the radio is not a problem. And we made sure to properly fix the RIO power supply

Without looking at the logs, I’ll share we had two instances of this at Tidal Tumble. We tracked it to the network switch we were using.
Radio was powered from radio power module (RPM) and was fine.
RoboRio had no issues.
The switch had a hotglued barrel jack for power, but under very heavy force, the switch would lose power and take 3-5s to restart. The ethernet from the Rio was routed into the switch, so for those 3-5 seconds we would lose comms, and be fine after. We removed the switch (and the raspberry pi it was connected to) and ran the Rio ethernet directly into the RPM and never had an issue again.

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When you’re asking for help diagnosing lost communications, how did you determine that the radio is not the problem?

I don’t have the ability to look at your logs right now, but I was curious as to how you elminated the radio as the source problem with your lost comms versus otherwise.

Also, how is the networking on your robot wired? Ethernet to the roborio is connected to what and where on the other end?

Right. I’ve eliminated the radio as a source of problems mainly because of this message that always appears in log events exactly when we lose comm.

"Warning 44002 Ping Results: link-bad, DS radio(.4)-GOOD, robot radio(.1)-GOOD, roboRIO(.2)-bad, FMS-GOOD FRC: Driver Station ping status has changed. Driver Station "

I didn’t notice any messages regarding the radio in the moments we lost comm during matches, is always this “roboRiO - bad”.

About the wiring, we just connect the radio to the RIO via POE cable (and ethernet cable on the other end) - exactly like this image.

When you look at your log events, how long do you have no communications? Is it for a split second, 3-5 seconds, 30+ seconds?

Also, how many brownout events do you see in the logs?

For understanding how brownouts may be affecting your robot comms, read through this:

Looking at your logs and match video, your roboRIO is power cycling in match. You can see the RSL turning off for a couple of seconds and then turning back on.

Match 4 -
Match 9 -

Check the power wiring from the battery to the roboRIO.

I’ve seen bad wiring make battery problems worse.

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Seemed like when the contact was on the RSL side of the robot, your Roborio rebooted. Try a little hot glue to hold those power wires in place on both the power and the Rio side.

Enable the robot and hit it with a hammer hard on that side to see if you can reproduce it.

I don’t think this timestamp is a rio power cycle. The RSL goes off for a few seconds and then starts blinking again, and the robot is moving throughout.

The robot does stop moving between 92s and 52s remaining in the match, although unfortunately the RSL is obscured. To me, that timing is in a grey area between radio & rio reboot. I would guess rio but I’m not really sure just from the video. The DS log messages that were shared seem to agree.

I definitely agree with your assessment for this one. The RSL starts blinking again about 32 seconds after it turned off. Too short for the radio to have rebooted.

I just linked to when the matches started. :man_shrugging: I probably should’ve clarified that.

In match 4 there’s a slight change in color at the 90 second mark below the grey wheels on the intake that to me matches the RSL turning back on. (I could be seeing things but it looks like the RSL to me)

I think you’re correct on that. I also think I see a reflection of the RSL starting to blink around the 59-57s mark. Pretty faint in both cases.

In match 4, based on the logs, the first short issue is brownout. The PDP is measuring 250 amps of current total, and that’s the most seen in the match. The second is roboRIO reboot. You can see this because of the log message 11:43:57.932 AM Code Start Notification.
In match 9, its also a roboRIO reboot.

I concur with the recommendation to check all wires in the path of the roboRIO (including battery wires).

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