View Full Version : Power Distribution Board
RoboBucs
05-02-2015, 16:33
Has anyone experienced problems with the 2015 Power Distribution Board? We have just now experienced 2 of the pairs of positive and negative ports not sending out any power. I'v tried it with different breakers, wires, and controllers that were all confirmed working. Is this something that can be fixed or will we have to get a new one?
nighterfighter
05-02-2015, 16:36
Are the ports outputting ANY voltage? Test with a multimeter.
Are the 2 ports next to each other? Are they the 40A or 20A ports? Are there any metal shavings that could be shorting something out?
RoboBucs
05-02-2015, 16:53
We currently don't have a volt meter so we tried shorting the wires and there was no spark at all. They aren't next to each other either, they are on opposites sides and a couple down from each other. They are 40A and we've blown into them and don't see any metal shavings in them at all.
RoboBucs
05-02-2015, 16:57
We did just try it with a volt meter and no power was coming from it
nighterfighter
05-02-2015, 17:03
We did just try it with a volt meter and no power was coming from it
Just to be sure: You did have a fuse in the correct place, right?
Also, I would recommend NOT intentionally shorting the wires together, just for future reference.
As for the problem at hand: Did this suddenly happen or has it been a problem all season? If it did just happen, what was previously connected to it?
And all the other ports are working fine? Does the roboRIO Web interface show any errors on the PDP?
RoboBucs
05-02-2015, 17:16
We had breakers in all of the slots so I know there was one there. This problem just recently occurred, it has had a motor controller hooked up to it all season and we recently took them all out. The wires may have been shorted when we took them out, would that have to do with it?
What do you mean by the "RoboRio Web Interface"? Is that the driver station in Labview?
Alan Anderson
05-02-2015, 17:19
We currently don't have a volt meter so we tried shorting the wires and there was no spark at all.
:eek:
The PDP (note: Power Distribution Panel) is built with seriously hefty copper traces. If part of it is not working when a breaker is correctly installed, it's probably physically broken such that I would expect the damage to be obvious.
Can you take a photo of it and show us what it looks like when it isn't providing power on the Wago terminals you expect it to? Give us a good look at the wires and the circuit breaker.
RoboBucs
05-02-2015, 17:41
Its the one on the right that isn't working. the left one is.
http://i.imgur.com/gi185vj.jpg
Most common symptom I've seen is releasing the WAGO connector in such a way where it pinches the insulation instead of the copper.
Try the attached test procedure to see what the problem is.
Thad House
05-02-2015, 18:07
Why do you guys have Red and Black inverted on that 30A breaker. Could that cause the problem?
RoboBucs
05-02-2015, 18:26
I did all the voltage testing, and there was no voltage coming from the wago connectors. I also didn't experience any voltage through the breakers but it was the same for all the breakers that were working too.
Concerning the black and red switched wires, some of our guys had to solder the wires and they soldered the red to the ground port and the black to the positive port because it wasn't labeled on the camera they were soldering it to, so the red is actually the ground and the black is the positive.
... I also didn't experience any voltage through the breakers but it was the same for all the breakers that were working too.
This does not help us deduce what is going on. Did you make contact with the exposed metal portion of the breaker (please see P1 and P2 in the pic to find the exposed metal).
rich2202
05-02-2015, 18:41
Try swapping the breakers in #6 and #7.
Power on the robot, but don't try to do anything.
See if you get power in #6, and not in #7. It could be a bad breaker.
Put the good 20 amp breaker back into #7.
BTW: what camera are you using? Most are 5 volts, and can't be powered directly from the PDB.
You will have to fix the wire coloring before a competition. Robot Inspectors will ding you for that.
RoboBucs
05-02-2015, 18:57
Okay, i corrected that error. I am not getting any voltage from the non working slot through the breaker and I am through the working slots and their corresponding breakers
Okay, i corrected that error. I am not getting any voltage from the non working slot through the breaker and I am through the working slots and their corresponding breakers
You're not getting 12V at both P1 and P2? Is the meter's ground probe connected directly to battery's ground (step3)? Please be as specific as possible.
RoboBucs
06-02-2015, 00:48
You're not getting 12V at both P1 and P2? Is the meter's ground probe connected directly to battery's ground (step3)? Please be as specific as possible.
Yes, I did all the steps just as it says and I didn't get any voltage reading anywhere on the bad ports, but when i tried the exact same thing on the good ports, I got voltage readings at all points. It isn't the breaker because I've tried switching the breaker to other ports that work at it works.
Concerning the black and red switched wires, some of our guys had to solder the wires and they soldered the red to the ground port and the black to the positive port because it wasn't labeled on the camera they were soldering it to, so the red is actually the ground and the black is the positive.
Be sure to remedy this before competition:
R40 All non-SIGNAL LEVEL wiring with a constant polarity (i.e., except for outputs of relay modules, motor controllers, or sensors) shall be color-coded along their entire length (from the manufacturer) as follows:
A. Red, yellow, white, brown, or black-with-stripe on the positive (e.g. +24VDC, +12VDC, +5VDC, etc.) connections
B. Black or blue for the common or negative side (-) of the connections.
Wires that are originally attached to legal devices are considered part of the device and by default legal. Such wires are exempt from R40.
We had breakers in all of the slots so I know there was one there. This problem just recently occurred, it has had a motor controller hooked up to it all season and we recently took them all out. The wires may have been shorted when we took them out, would that have to do with it?
In the future, please open the main breaker and disconnect your battery before doing any work on your wiring.
You may also want to find out if there are some established teams in your area who can help your team climb the learning curve. You will enjoy the experience much more.
RoboBucs
06-02-2015, 15:32
Are the motor controllers able to run off of the 30 Amp ports? If so then I won't need the ones that aren't working
Jon Stratis
06-02-2015, 16:51
Concerning the black and red switched wires, some of our guys had to solder the wires and they soldered the red to the ground port and the black to the positive port because it wasn't labeled on the camera they were soldering it to, so the red is actually the ground and the black is the positive.
Quick note on this... You need to get those wires removed and attached correctly. R40 specifies the correct color coding for all non-signal constant polarity wires, which includes those. If you don't fix it before you nah, your inspector will make you fix it at your event.
Al Skierkiewicz
07-02-2015, 08:29
Buc,
It is possible, but highly unlikely, that you could have damaged the PDP for one or two outputs. We have found on multiple PDPs, that the terminals for the breakers do not line up with the slots in the PDP cover. If this breaker is easier to insert and remove than the other slots, you are likely missing the terminals inside the PDP. At least one of our PDPs is going back because we can't even see the terminals through the slots.
Yes motor controllers can be run from 30 amp breakers and even 20 amp breakers if you are so inclined. However, the breaker is not a current limiter. I have seen some teams use them as such. A CIM motor will still draw 131 amps in stall even if connected through a 20 amp breaker. (For a short period of time.)
One phrase we have used every year...
If you had time enough to do it again, you had time enough to do it right the first time.
Living with color mis-match on power wiring is an accident waiting for a place to happen.
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