Redundant Power Sources for Electronics?

To prevent a power wire from coming out of some critical electronic and ending your robot during a match, is it safe/possible/legal to power a single electronic component through multiple ways?

I’ve heard talk of using both a POE injector and the barrel connecter on the radio, if one comes out then there is the other to keep it on.

Team 254 also recently posted a picture of their robot base with electrical, and it appears that their RoboRio 2 is powered through the power terminal AND a POE injector (while there radio only uses a barrel connector):


Is this safe or recommended to do, and is there any considerations you need to take into account while doing something like this?

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I can’t think of a reason it would be illegal, but I also don’t think the RIO supports PoE, and it definitely wouldn’t need to be powered from the VRM if it did. Given that this is an in-progress picture, I think this might just be a case of a mistaken student rather than a secret new wiring strategy.

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They might just be using the poe injector as a remote Ethernet port

yep, the rio is not redundantly powered. another late night, just an erroneous connection as we get ready to add the swerve and drive the following meeting. In our reveal picture, you can see the radio is mounted on the superstructure.

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To more directly answer your question, the radio is the only component of the control system that can be redundantly powered. HOWEVER, it can only be redundantly powered with the barrel jack if the other power source is POE injection via the VRM. If you are powering your radio over POE using the Rev RPM, you should not use the barrel jack as well since the RPM powers the radio at 18V while the barrel jack runs at 12V.

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Does it have to be a VRM, or can it be the low-current channels on the Rev PDH?

Your only options for powering the radio are the VRM and the RPM. The low-current channels on the Rev PDH are not voltage controlled - you’ll drop your radio if you try to power it directly from there.

What @Jon_Stratis said. Reference robot construction rules R616 and R617 in the manual.

I wish FIRST would open up the ability to use 2 RPMs where one is POE and the other uses a POE splitter cable like Passive PoE Injector Cable Set : ID 435 : $5.95 : Adafruit Industries, Unique & fun DIY electronics and kits. As for whatever reason my team ended up with 20 sets of these.

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