Hello! We recently realized that we are lacking slots on the PDH to accommodate all of our components on our robot. Our current breakdown is:
Depending on the draw, you can sometimes run multiple circuits (ie, encoders, coprocessors, etc) off of one slot of a VRM or Mini PDH. You could try consolidating your 2 Mini PDHs and 1 VRM down to just 1 total, which would bring your total number of slots used to 20.
Just make sure you don’t have more than one wire coming out of each port on the PDH (Rule R618)
No
Thank you so much!
You can always put unlimited devices behind a kraken powerpole adapter.
I feel like you might have problems reaching the end of the game with that many motors. Speaking from expérience from a team that doesnt use pneumatics since 2019 (all electric actuators) you might find a better solution looking into better gearbox ratios. How are your motors distributed between systems ?
This is so many motors…
How many do you have powering the same degree of freedom? (I.e. 2 motors powering the intake deployment). If you feel comfortable sharing a little more about your bot we may be able to help a bit more. I suspect you have 8 motors on swerve, what is the rest of the mechanism breakdown?
Remember you can have multiple motors run off of a single speed controller in a few cases (bag motors). Useful for lower power things (like teams running one bag on an intake and one bag on the color wheel in 2020), same controller.
Maybe. But everyone has limited space for mechanisms. So I suspect a lot of these aren’t drawing a lot of power over the match. But that is just a guess.
2 motors driving intake pivot
1 motor driving intake roller
1 motor driving indexer
2 motors driving shooter flywheels
1 motor driving pivot of shooter
2 motors driving two separate arms for climb
8 motors for swerve drive
1 motor preferably 2 for amp mech
for sensors and other random things we have 2 mini pdh’s and a vrm
To be fair, the indexer appears to work completely passively so we may be able to get away without that one.
You are correct with the power draw assumption, practically everything other than swerve either only runs part time or has negligible continuous draw (i.e. flywheels)
What are you doing with 2 mini pdhs and a vrm damn
How so?
browning out is an art form
You are correct the handoff indexer is passive but shooter indexer is not and requires the aforementioned motor.
If there are no actuators on the Mini PDHs, you can power both of them off of the one PDP slot that is not being used for motors, since they are a custom circuit. Based on my reading of the rules, CTRE VRMs not used to power the radio are not custom circuits, and so couldn’t be powered off the same branch circuit as the mini PDHs under R621. You could get around this by using a voltage regulator from another source (a lot of people on CD have recommend pololu).
If you have a servo power module, I believe there’s currently an issue with the rules where the servo power module isn’t properly accounted for. I’ve asked a Q&A question to clarify that: FIRST FRC Q&A System
The easiest solution would be to use less motors. And you might realize your robot is more maintainable and robust as a result.
Lots of sensors and cameras I think. @RomanTechPlus would know better!
Is my interpretation of Q127/Team Update 08 that power a motor controller from the Low Current/ATM Fused slots on the PDH is legal? That would theoretically give 4 more slots that are protected by a 20Amp Fuse.
This is clearly a bad idea, but something that had never really occurred to me before the team update.
Well, in this teams case, you could definitely use the two fused supplies not used for the RoboRIO and the Radio for the mini PDHs and the VRM.
