Can I attach a VRM to a Rev PDH

We got a Rev PDH. Wondering if we can attach a VRM to power our radio? There isn’t a dedicated slot like in the PDP. Is it possible? and how? Thanks.

Yes you can attach it to your PDH we did that this year and it got power from the low current channels although we didn’t end up using the VRM

This wiring graphic shows how REV recommends powering your radio.
We typically use port 20.
In regards to the VRM you can use it with the PDH quite easily. We also use the mini power module for a variety of sensors.

Hello. Thanks. Are the low current channels the ones near the bottom of the PDH, with the small push in connectors? What breaker did you use? Appreciate it.

Thanks. Can you use the VRM to power both the radio and the canencoders at the same time? If so, do you connect the VRM to a regular port on the PDH? What fuse would you use? And what ports on the VRM would you use for the canencoders? Appreciate your help.

R617B describes how a VRM powering the radio must be attached to a PDH.

It is possible to use a VRM to power both the radio and CANcoders. R616A would restrict the CANcoders to the 12V 500mA ports on the VRM if it was also being used to power the radio from the 12V 2A ports.

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These are the legal ways to power the radio: Legal Options for Wiring your Robot Radio in 2022

It applied beyond 2022 for 2023 as well and I would wager it will be that way for 2024.

VRM is perfectly legal to use with the PDH. I would highly suggest you not power things other than the radio with the VRM if it is powering your radio. Could look at secondary VRMs or other regulators for powering other devices.

Thanks. Appreciate the clarity. Just to double check: Connect the VRM to the PDH using the low current channels (20-22) with a 10A fuse. Then connect the radio to the 12V 2A port. And the CANcoders to the 12V500mA port? Then we could use the VRM with the PDH for both the radio and the CANencoders. Do I have that right? Thanks.

Yes they are

Page 7 of the VRM hardware manual says to use a 20 amp fuse to power the VRM. The Cancorder Manual states that the typical input is 12 V and 50 mA. With the CANcoder you need to solder wires to it (unless you bought them presoldered). I know of a team that didn’t think of that and didn’t own a soldering iron. I am pretty sure we use the Mini power module to power our canencoders. It just connects to one of the PDH ports.

If a VRM is being used to power the radio and that VRM is being powered by a Rev Power Distribution Hub, the 2023 rules require that the VRM is wired to one of the unswitched low-current ports on the PDH (20, 21, 22) and that port must have a 10A fuse installed.

If a VRM is being used for devices not including the radio (an “additional VRM”), that VRM can be wired into a high-current port on the PDH with up to a 20A breaker. However, a VRM wired this way cannot be powering the radio.

20A fuses cannot be used in the PDH to power any device/circuit other than a PCM or PH.

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Yes, this is right.

Many will suggest that if a VRM is being used to power the radio, that no other devices should be powered from that VRM. This is not a limitation of the rules, but rather the voice of experience. If there is any problem in your CANcoder wiring or the devices themselves that blows the fuse to the VRM, your robot will not function for the rest of the match. If you brown out the radio in a match, it will be a while before it reboots and allows you to drive again.

If this robot is for off-season competition, the potential consequences of adding CANcoders to the radio VRM are not too bad. For in-season competition, the prevailing wisdom is to power the radio with a dedicated regulator.

There’s no reason (unless you use all of the PD ports for non CUSTOM CIRCUIT stuff (like actuators and mandatory components)) to do it rather than connecting them directly to the PD(P/H).

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