Brownout Protection Error on Driverstation

So our team was practicing for a postseason competition when one of our intake motors stopped working. We assumed that it was a connection issue so we re soldered both leads to the motor.

Since then our robot went from rapidly phasing in between teleop and brownout protection to completely stuck on brownout protection.

Here is what we’ve determined so far:
The battery reads ~13v
Input power to PDP is ~12.6V
We have unplugged all motor controllers from the PDP to check for shorts and no change
We have checked the resistance between every port of the PDP and their respective battery connector lead
Apparently, the motor was accidentally resoldered as the robot was on, but we are unsure if that would have caused an issue
No shorts with the frame
Not sure if this would change the problem, but our robot spent one week of the summer in a shed filled with lots of moisture so some bolts have become rusted including the bolts for the input leads to the PDP
Robot ran fine for about 2 weeks of practice

We have genuinely run out of ideas, so any help would be greatly appreciated.

Try using a different PDP. Disassemble the PDP that you have and check if any internals are burned. We have shorted out channels on PDP’s, and if I recall people posting pictures of burnt PDP traces here.

Have you tried removing all the breakers from the PDP as well?

Can you check the driver station logs to see if it shows a PDP channel drawing current?

Thanks for your suggestions. Unfortunately, we just checked for all three of those and none of them worked. We discovered that our pdp is reading a sticky fault error. After we finished working and went home today, we discovered that its possible that this error was tripped and hasn’t been reset since. Our current hypothesis is that when we accidentally re soldered the robot while the motor was on, it triggered a sticky fault that hasn’t been reset yet. We haven’t been able to try this fix next, but we think that its either this or the pdp is broken. What makes us think that its we disconnected everything except for the roborio, breaker, and pdp and the roborio was receiving only .02 volts less than the pdp which would make sense. In that configuration, we still got the same error. That leds us to believe that its the stick fault error that hasn’t been reset or a broken pdp.

A PDP sticky fault is just information. It doesn’t disable anything.
You can check to see what the fault is through the roboRIO webdash, if you can get the roboRIO operating on a different power source.

You can try powering the roboRIO from:

  • A different PDP output-any output will work
  • A VRM connected to the PDP-also any PDP power output will work.
  • A separate wall power supply (7-16v, at least 1amp)

It all sounds more like you might have a roboRIO issue, rather than a PDP issue, since you say that you already tried a different PDP.
Trying a different power source will help isolate the problem to the PDP vs the roboRIO.

Alright so we were able to self test the pdp through the roboRIO web interface and we discovered that one of the channels was drawing 17+ amps. We assume that this is likely the problem and will research exactly how to fix it or if we need a new pdp. A screenshot is attached for reference.

Depends on what you have connected to that PDP channel.
As part of your testing see if the reading persists when you pull the breaker for channel 2.

As you can see, the sticky fault is because your battery fell below the brownout stage at some point in the past. That’s a pretty common sticky fault that most teams have.

When we ran that test we actually had nothing hooked up to the pdp except for the Rio. There were no breakers in any of the channels. So that was what lead us to believe that it is an internal problem in the pdp.

Is your PDP on the latest firmware version? (v1.4 here)

I seem to remember there being a firmware update correcting a bug where empty PDP slots would show phantom currents. If not, try updating the firmware and see if the problem goes away.

Even 0.5A with no breaker would be concerning to me. One thing is with that much current should cause quite a bit of heat (maybe smoke) if it’s actually flowing.

Note brownout happens when measured RIO voltage drops too low, not when the measured current is too high - so the implication is that if you’re seeing brownouts, you actually have that much current flowing… somehow…

Original versions of the PDP firmware miscalculated the current readings and would show readings similar to what was posted.
The roboRIO webdash will show the PDP firmware version at the bottom.

In addition, (assuming the 17A is real) 17A should not be enough to brown out a roborio powered by a charged battery. If your battery voltage continues to show 13V when enabled, you are definitely NOT drawing enough current to brownout anything at all. Brownout protection kicks in at something like 6.X volts.

It’s possible that the roborio power circuit on the PDP is faulty.

Try powering the roborio from one of the wago connectors on the PDP with a 20 amp breaker to rule out the roborio power circuit on the PDP.

You could also power the roborio from another suitable 12V source to triple check.

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Just checked and the pdp version is 1.4 so that shouldn’t be the issue. I switched the roborio to the wago connectors, and it had no robot code but it did not have the brownout error. I also powered the roborio from a wall powersupply and there was still no brownout error. I have attached some more screenshots of the rio information, pdp information, and driverstation log. At this point, we need to determine what we need to replace, not necessarily what the problem is because we are headed to a post season competition next Saturday.

The descriptions sound like two problems:

  • the PDP roboRIO power connector has an issue
  • the PDP current sensor circuits have been damaged (not critical as it doesn’t affect normal PDP power distribution)

One further thing to check is inspecting/replacing the PDP’s red 10a fuse on the roboRIO power output. It’s the only other user serviceable part.

For an off-season event I’d say just run with the roboRIO powered by one of the larger wago connector with a 20a breaker.
As an alternative, if you have spare connections on the PDPs 20a fused connection for the VRM/PCM, you can use one of those.

For regular season it certainly sounds like a new PDP could be in order.
You can probably get an on-site second opinion at your off-season from other experienced teams.