Our team is using a long version of the Kit Bot drive train and we mounted our Power Distribution Board under the motors. We are now concerned about visibility during inspections as covered by the rule…
R42
The PD Board and all circuit breakers must be easily visible for Inspection.
We think it is visible, you can see the wires connected to the board, the breakers on the board, and the connections for the Radio power supply and cRIO. It does take some effort, looking around the motors and removing the battery, but we think the board is visible, the part that worries me is the word “easily”.
Reconfiguring the electronics board at this point would be tough.
Looking for opinions of what we might face during inspection.
Tie the wires together, label and shorten them as much as possible. The longer an inspector spends with your robot the more things they will find wrong.
I believe inspectors have to make sure the correct snap-action breaker is in the correct slot. From the perspective of the picture (I would call this the “easy perspective”) you cannot do that therefore you would fail inspection until the breakers were visible. Last time I was an inspector at a regional was 2011, so if I am wrong and something has changed please let me know.
Also if any of your breakers fail during a match how do you expect to replace them? Place your PD on top of the hex tubes instead.
This is a good thing! The inspectors’ job is two fold:
Ensure finger count and blood volume constancy.
Maximize the time you spend *working *on the field.
I would argue that R42 should read:
The PD Board and all circuit breakers must be easily visible so that issues with your wiring can be identified and fixed quickly, during inspection or otherwise, because you really really want to spend as much time as possible playing and not fixing.
… but then the rules would reach 200 pages.
So, regardless of whether it would pass their inspection - would it pass yours?
Looking at this picture, inspectors would have to suffer quite a bit to see the breaker ratings and what wire size goes into which wago. It’s also going to be a giant pain to work on if it breaks. I’m assuming there’s going to be more robot above this part, which is only going to make this harder to deal with.
One other thing to consider is that gearboxes innately tend to leak tiny metal shavings. With this design, gravity is not your friend.
It seems that you would have a pretty hard time adding/adjusting anything in your electronics with that setup. If you guys have the space, mount the PDB directly above the motors while using some plastic on top of the 2 braces you guys have between the motors. Then send all the wires under the board using the braces to channel and hide any spare wire you guys might have. If that isnt an option then just try to make the wires neater by sending the wires under the current mounts that you have and along the interior so that the inspectors have a clearer view of your electronics. Hope this help.
Richard, I don’t know what you’ll face during inspection, but I would not want to have to work on your robot with it built like that. We learned that our rookie year…the electronics need to be easy to get to, period.
With that setup, you’ll make your inspector very unhappy, as they’ll have a very difficult time seeing what they need to see.
Rather than reconfigure the board, is it possible to add a hinge on the bottom? Our electrical board is likewise at the very bottom of our robot under other stuff, but we have one side of the board hinged and the other bolted. For inspection, we tip the robot on its side, remove two bolts, and the whole thing is very, very easily visible!
Even if inspection isnt an issue they still need to be able to reach their electronics with some ease in order to make any adjustments. You always need to plan for the worst and I dont think spending a bunch of time on just reaching the electronics is great especially if they need to make quick repairs or additions during a competition.
I sure like the hinged electronics board idea, makes for easy inspection and service. The wires on the voltage side of the Talons run inside the C-Channel and might make it tough to hinge in our case.
I can reach in with my hands and change breakers. The wago connectors on the non-battery side are positioned so I can fit the screwdriver in and change a wire (the battery side is more difficult, but three bolts and the battery case is off the electronics board).
Metal shavings coming out of the gear boxes is now concerning me as well.
Mounting on top of the transmissions is out because the shooter will be above the transmissions and when down will not leave any room to mount anything up there. When the shooter is up, there is plenty of room to see through the motors. Might have to see if there is a way to raise the shooter to make room for the PDB.
Prior to wiring the robot, we put together a spreadsheet showing the motor, speed controller, wire size, and breaker size. This comes in handy during inspection, because typically the inspector will look at the spreadsheet, and then spot check one or two breakers.
Field personnel really need to have easy crio, radio, and main breaker accessibility. Safety is also a significant issue behind this rule.
Also if you plan on hanging, and having anything in zone 3, (even if its a 1/4" of aluminum) make sure you can turn the robot off from the ground easily.
Our PD board was pretty obscured last year (we put it vertically behind our collection mechanism) and Big Al gave us a talking to at Champs. It’s unlikely they won’t pass you because of that considering the amount of work it would take to relocate something the magnitude of the PD board but I can guarantee you the inspectors won’t be happy about it. Remember, they say it must be visible for inspection, not visible for gameplay so if you choose to have it mounted on some sort of hinged mechanism it is still legal.
As Grim Tuesday noted, as an inspector I would be unhappy with that, but eventually I would pass it. Good luck changing out a wire or breaker in a hurry!
Please do. From what it looks like in that pic, the main breaker isn’t very accessable and might need to be moved. To answer your original question, I’d be very unhappy if I had to inspect that PDB location. I’m sure it’d take more time than either of us would like to finish.
But chiming in as a team member…why would you do that to yourselves? I can almost guarantee that you’re going to regret that location during some point in the season.
Remember that although the slots have a pretty good grip, the only thing holding the breakers in is friction, and in that orientation gravity is working against you.
Also, ground clearance might be an issue depending on your setup. I’d hate to see you smash the PDB into the bump around the pyramids (or snag wiring on a frisbee you’ve run over). ::ouch::
