Are these PDP kJoule readings normal?

Does this look normal?

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What’s attached to it?
Also one joule second is a volt ampere, you can look that up online and see what voltage and current you’re pulling from the port

What are you trying to find? An energy reading by itself isn’t very enlightening in many contexts.

Yea, I’m not sure the units are correct. For example, port 0 at 24kJoule, / 12V = 2KAmp ???


Depending on how your getting your data, there’s a scaling factor.

We don’t have motor controllers plugged into all of those channels/ports. But we have do have 40amp breakers in all the slots.

That’s fair! Our robot had so many electrical problems for the past two years, I’m just anxious. We replaced the roboRIO, PDP, VRM this year and I’m afraid that I’m going to damage them by making the same mistakes as in the past.

But I can’t exactly say what those mistakes were! I’m poring through old log files from the driver station and trying to see patterns. These numbers seem so high to me.

I got the data from a log file from the driver station.

This sounds like XY. If you ask about your actual problems instead, you may be advised solutions.

What do you mean by XY?

Can you talk about what electrical problems you have had in the past?

Those that caused the robot to stop working mid-match. Which is why I’m looking for patterns in log files from the past couple years.

Thank you for your time.

Let’s try to break this down a little bit. The first key is to figure out which component, or multiple, was going wrong.

Did the entire robot stop working/moving, or just certain systems? Did you still have connectivity on the driver station (3 Green indicators)? Did it die for the entire match, or did it come back to life? If the latter, how long was it typically out? A short loss in connectivity (10-30s) could mean your Rio dropping out. Anything longer than that is probably the radio. Or it could be both.

Could it be a code issue? Are you browning out?

Do you have some reason to believe that the components are damaged physically?

kJoule / Volt does not equal amps. 1 watt-hour = 3.6kJ. 24kJoule / 12V = 0.55 amp-hours. If this is C++/Java and nothing was plugged in to the PDP ports, then .0055 amp-hours (or .132 amps*2.5mins scaled to a single match) could very well be noise on the current measurement integrated to provide an energy number.

Is this signal noise something I should try to lessen?

If you’re trying to solve electrical problems that caused the robot to stop working, this would not be the place I would start.

Without a time machine, it’s all I’ve got.

The units are indeed correct as it’s from the driver station log viewer, it’s probably calculated by integrating Total PDP * voltage.

This values do seem a bit high if this was a single match for me… Could you maybe upload your log file? I can see if there is an issue.

When I initially looked at OP, I thought it looked a bit weird, but knowing that this is from an FRC match, WOW, THAT’S WEIRD!

All 16 channels are apparently connected. The smallest number of the 16 is 15.48kJ on channel 9, and the greatest is 28.75kJ on channel 14.
That’s about ten sigmas (rough estimate) out of normal. I’d be surprised if 3% of teams actually use all 16 PDP ports, and the concept that the smallest custom circuit or conveyor drew more than half the energy of the highest-energy drive train or shooter makes me serioiusly question if even the truly elite teams would want to, much less actually meet, meet that criterion.

There is a bug with reporting PDP channels in the logs where channels report at around a constant 2A even when they should be 0. So say the robot sits for 5 minute before the match then 12.2V*2A*0.12Hr*3.6= 10.5 kJ is the baseline. This could be happening here.

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