PDP not receiving power but everything else is?


So as you can see, both lights are off. I think this means that PDP isn’t receiving power but everything else connecting to it is receiving power and can run fine. Not sure what the issue is some help would be appreciated.

Also the roborio shows a green comm light.

That usually means that the CAN board in the PDP has been fried. That would be caused by reversing the polarity to the main input on the PDP, among other things.

You can try using the Phoenix tuner to see if it identifies the PDP on the bus. In all probability though, it won’t appear there and you’ll need to get a new PDP. As is it’ll work for a practice robot, but you won’t pass inspection without a CAN connection. You can try contacting CTRE to see if they’ll repair it for less than the price of buying a new one; they have pretty good customer service so they might be able to.

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I see where the rules require the CAN connection has to be made, but I don’t see anywhere that says that it has to be functional.

:expressionless: This is the kind of rule lawyering that makes the manual 125 pages long. It’s clear that “The PDP CAN interface must be connected…” means connected and functioning. The rule is there for your own benefit so if your robot dies on the field you have a log showing important diagnostic data.

Edit: if you really want to try it, you can ask the Q&A if the CAN interface on the PDP has to be functioning to satisfy R79. But I think you already know what the answer is going to be.

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There seems to be a fair amount of what looks like aluminum swarf (particles) .
You might want to remove the PDP and the fuses and tap it upside down on some paper. If there is a bunch of debris, betting there is, you probably have damaged the CAN circuitry. You might be able to vacuum out more particles and get it going again though doubtful.
We have lost a PDP a few years back in competition in the same manner. Once we returned from competition we took it apart found quite a bit of aluminum inside.
I would do as @AriMB has suggested and contact CTRE, they are good to work with.

I will mention that part of the inspection process is verifying firmware version on the PDP, if an inspector is unable to verify the firmware version in the DS, you would not be able to pass inspection.

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We typically don’t comment on rules, but given that we had a hand in this one I feel it’s appropriate.

For those that don’t want to look up the wording, I’ve copied a screenshot below:
image

To comply with R79 you only need to have the PDP CAN connection physically wired to the roboRIO (and as the rule mentions, daisy-chaining is fine). As long as you have a working PDP this accomplishes the goal you mentioned of ensuring PDP data is available in the Driver Station log.

The rule is as-written precisely because having a team not pass inspection due to their PDP failing in an unusual way (that doesn’t affect safety or performance) is something we didn’t want.

By all means I encourage you to ask the Q&A question so you have confirmation through official channels (and no, me posting on CD is not an official channel), however we (CTR Electronics) can confirm that my statement above is the intent of that rule.

This isn’t the case anymore - as of 2018 there is no rule or part of the inspection process that specifies or checks firmware version on the PDP (or PCM).

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How would everything run as theOP said if the CAN is fried? Just inquiring. Reversed input polarity on a PDP early this build season and if seems to still be working.

CAN is just used to obtain sensor readings, e.g., draw on each power port.

CAN doesn’t control the power paths in the PDP, those are just straight electrical power paths, breaker contacts, and breakers.

Sadly we just ran into this today… The PDP works fine, even the CAN, just the status lights on the PDP do not illuminate… I have swapped out our PDP for a new one and everything is working correctly now.
Have to bag this ready to pass inspection once we arrive at our regional competition.
I have taken apart the failing PDP and found aluminum swarf on top of the small circuit board that runs the CAN/LED’s… We have marked the unit as a practice only part… Still functional just would not pass inspection for competition. If time permits I will send it in for possible repair.

It is likely that you are doing construction work above your electronics panel causing metalic debris to fall on the components and get trapped inside them. It would be a very good idea for you to stop now and carefully and thoroughly vacuum out ALL of the debris. Any further construction should be preceded with covering the electronics panel with something to keep the debris off it.

For future robots, you may want to mount the electronics panel in a vertical orientation. It is less likely that debris stays on the components so less of it works it’s way inside.

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