How to determine root cause of robot dropping from Teleop to Disabled during match.

[Alan Anderson]

Originally Posted by tr6scott

We also checked all of the fuses after this match, and nothing was found to be loose.

The way you worded that makes me wonder if you are talking about the right thing. The 10- and 20-amp PDP fuses are the important ones here. They're the red and yellow miniature automotive fuses on either side of the Weidmuller terminals for the roboRIO, PCM, and VRM power. If one of them has an intermittent contact for a moment, the roboRIO loses power. If the other one fails briefly, the VRM (and thus the D-Link) loses power.

Even if not fully seated, they usually won't feel loose. But not feeling loose doesn't mean they are making proper contact. If you can pull them out by hand, they weren't in all the way. It takes some serious pushing to get them in correctly, and once that's done, they definitely won't come out on their own.

[tr6scott]

Alan,

Yes, those fuses were included in the "All fuses" were checked. We experienced a disconnect at our Waterford event (Week2), and when we were alerted of the problem, we found one of the ATM fuses to not be completely seated. Having already been through this scenario once this season, that was the first thing I had instructed the pit crew to confirm as they were fixing the elevator after the match.

But I am now going to go back to those logs and review that match too.

[notmattlythgoe]

We actually had a match at VA that our robot code just stopped running. FTA said the rio never disconnected from the field. No errors on the DS stating any code errors that crashed it. It just stopped. Never figured out what the issue was and it didn't do it again.

[tr6scott]

Alan,

Follow up on Waterford event.
Video: https://youtu.be/Ai4AiWz7680

at 57 second on video you see the stacklight flash.

You also see our drivers struggle with that stack after restored.

FTA came to us with the issue, and mentor said one of the ATM fuses was not seated completely, he felt the fuse move, and seat when he pushed on it.

As this was Finals Match 2, not much done after this to diagnose the issue.

[Monochron]

We had a very similar situation in our quarter finals match. The first one we exhibited similar behavior all throughout teleop (autonomous went fine). The second match we only dropped out for about 30 seconds or so. The DS logs showed that we lost communication with the FMS for the duration of those times. CSA's suggested that this was caused by our radio losing power, but it looked like they couldn't investigate the issue further than that.

I'm eager to see if you can resolve this, and I'll see if I can make any progress on evidence for what caused our problem.

[plnyyanks]

Originally Posted by Monochron

We had a very similar situation in our quarter finals match. The first one we exhibited similar behavior all throughout teleop (autonomous went fine). The second match we only dropped out for about 30 seconds or so. The DS logs showed that we lost communication with the FMS for the duration of those times. CSA's suggested that this was caused by our radio losing power, but it looked like they couldn't investigate the issue further than that.

It sounds like the CSA was on to something - a radio reboot typically takes between 30 and 40 seconds to come back (the DS logs tell you exactly how long your robot was down). In contrast, a roboRIO will take around 25 seconds to reboot.

Common causes of radio reboots:
- Brownouts due to your battery being low. These events correlate to large current draws
- PDP Fuses. Push them in all the way
- Multiple things plugged into the radio source on the VRM
- The barrel connector not being plugging in all the way, especially if it's an older one

[Monochron]

Originally Posted by plnyyanks

It sounds like the CSA was on to something - a radio reboot typically takes between 30 and 40 seconds to come back (the DS logs tell you exactly how long your robot was down). In contrast, a roboRIO will take around 25 seconds to reboot.

Common symptoms of radio reboots:
- Brownouts due to your battery being low. These events correlate to large current draws
- PDP Fuses. Push them in all the way
- Multiple things plugged into the radio source on the VRM
- The barrel connector not being plugging in all the way, especially if it's an older one

Yeah we didn't notice any unusually large voltage spikes in the logs but I'm still checking different possible causes.

[MrRoboSteve]

Also make sure you are using the appropriately sized barrel connector. If the outer diameter is too small, intermittent power is possible.