Power Converter

[ebarker]

In the black tote in the KOP is the following item. Where can I get more ? It isn't on the 'get more' datasheet

Power Converter 360 CPR

[Mark McLeod]

If it helps the search it's a 25w DC-DC converter
12v to 5v/5amp

It's purpose is to power the new robot access point/radio.

I think it's this one $14.50

[ebarker]

That was quick, thanks. Beats having to build one every time you need one.

Ed

[Mark McLeod]

I'm preping for a Saturday KOP workshop, so I had already collected the specs on it.

[JohnHorton]

When we unpacked that, we all wondered "What the hell could draw 25w at 5v?". That would be quite a few LEDs...
Took me a while to realize it was for the D-Link.

[kamocat]

The FIRST wiring diagram shows it coming out of the regular 12v power supply for the Robot Radio, and then going through this DC-DC converter.

The thing is, the power supply for the robot radio already has a DC-DC converter (it keeps it at 12v, even if the battery drops below).

Has anyone tested this?
Won't there be horrible harmonics from powering one switcher off another?

[Mark McLeod]

They were tested on selected 2010 robots beginning in September at several off-season events.
My image was actually from an October meet.

That doesn't mean we shouldn't put them through tests ourselves now that we have them in hand.

[kamocat]

Originally Posted by Mark McLeod

They were tested on selected 2010 robots beginning in September at several off-season events.
My image was actually from an October meet.

That doesn't mean we shouldn't put them through tests ourselves now that we have them in hand.

What do we do if we find a problem?
Are we allowed to simply attach the converter it to a WAGO terminal, or simply use the camera power supply?

[EricVanWyk]

Originally Posted by kamocat

Has anyone tested this?

Yep.

Originally Posted by kamocat

Won't there be horrible harmonics from powering one switcher off another?

I sure hope not...

[EricVanWyk]

Originally Posted by kamocat

What do we do if we find a problem?
Are we allowed to simply attach the converter it to a WAGO terminal, or simply use the camera power supply?

NO.

This would make the radio the first thing to die when the battery voltage sags. This configuration will lose matches. I hope inspectors pay extra attention to this circuitry.

It isn't optimal due to design history (PD designed for 12V router, switched to 5V router without redesigning PD), but it works. The theory is that the PD can put out 12V all the way down to 3V, and the external buck takes it down to 5V. Without the PD's 12V boost, the router will collapse somewhere north of 5V.

[Mark McLeod]

Ow! My eyes, my eyes....

[EricVanWyk]

I'm sorry...

My worst experience in FRC was telling a team that the reason that they lost the deciding match was that they had wired their router in a manner similar to what Marshall proposed.

It was 1 to 1, and the winner of the match would be regional champion. Halfway through the match, they were up and looking to win... until they got the dreaded no comms error and froze for well over 30 seconds. The other alliance pushed the advantage and won. A replay request was made, and I was the guy who had to tell them that the fault was in the router power wiring. It had worked perfectly well through the entire regional until that deciding moment.

It was technically the correct call, but I've lost a good bit of sleep over it since.

[kamocat]

Interesting. I didn't realize the Robot Radio was the only one that dealt with low battery voltage.
Sometimes I think it'd be nice to have separate batteries for the control system and the actuators, but then I remember how much I disliked that on the 2008 control system. Oh well.

I might put an O-scope on it just for fun. Do you think the D-link Robot Radio is sensitive to noisy power supplies?

[EricVanWyk]

Originally Posted by kamocat

Interesting. I didn't realize the Robot Radio was the only one that dealt with low battery voltage.
Sometimes I think it'd be nice to have separate batteries for the control system and the actuators, but then I remember how much I disliked that on the 2008 control system. Oh well.

I might put an O-scope on it just for fun. Do you think the D-link Robot Radio is sensitive to noisy power supplies?

The cRIO and the radio are designed to operate down into the 3V range. The rest of the system is designed to shut down at 5.5V. If it is going below 7-8V, you really need to recharge the batteries.

The D-link i used to being powered by a cruddy wall-wart, so I don't think it'll mind. It actually has its own switching regulator on the input, so there are 3 in series

[DavidGitz]

Originally Posted by EricVanWyk

I'm sorry...

My worst experience in FRC was telling a team that the reason that they lost the deciding match was that they had wired their router in a manner similar to what Marshall proposed.

What exactly did they do? How did they pass inspection? It was probably overlooked, but still, wow.