Currently on our robot we have an OpenMesh radio wired into the VRM on the 12V 2A port. We want to add a GO-SW-5G ethernet switch so that we can connect our coprocessor to the radio. However there is a rule for robots that the radio must be the only thing connected to the VRM.
Robot Radio – A single OpenMesh OM5P-AN or OM5P-AC radio must be powered via the VRM +12 volt, 2 amp output and
must be the only load connected to those terminals. VRM connected to dedicated +12 volt output on the PDP. Radio must be
mounted so that LEDs are visible and the roboRIO Ethernet is connected to the 18-24 VPOE port. <R51, R52, R62, R63, R69>
This is from the 2017 inspection checklist. However last year we had LED lights wired into the VRM and the robot passed inspection. Was this a mistake? Or am I not understandig the rules properly?
The radio must be the only thing connected to the 12V 2A terminals. 5V 2A and 500mA as well as 12V 500mA are available. If you had LEDs plugged into 12V 2A you shouldn’t have passed inspection. For that you need another VRM.
First, do NOT use the 2017 inspection checklist to check 2018 robots. Just so we’re all aware, 2017 rules do not apply to 2018, unless they are also 2018 rules. You’re looking at R53 in this case, and it is, in fact, the same as last year’s rule (BUT not the same rule number). Also check R54 for where the VRM is getting its power.
Second, I would guess that your inspector last year made a mistake. It happens. If I had a nickel for every time someone told me “but it passed at ____”… I’ve caught inspection escapes a couple of times in the last few years. I’d go into stories but that’s not the point of this thread.
And then I agree with the previous poster: use an additional VRM, reference R58 for wiring details.
My team is using the network switch that was available in First Choice, and that makes it nice because that runs on 5V, meaning it doesn’t interfere with the radio.
The inspection checklist for this rule has not changed. However, you can use a second VRM. I highly recommend the second VRM for all other voltage requirements.
Thank you all. We wired our switch into the VRM’s 5V 2A terminal. Robot boots and runs fine. If we run into a problem with inspection at the competition we have an extra VRM we can use as a dedicated power source for the switch.
We’ve had good results using the Netgear ProSafe 5-port switch plugged into the 500ma ports. They’re fairly inexpensive and have a nearly indestructible metal housing.