Our Head of Electrical decided to make a modular electrical system. He thinks modular means taking out the entire system if it fails, so we’re just playing along. We’ll have a spare of the system in the pits during competition.
I really like the idea in a lot of ways, however a minor nitpick- if I had to figure out what was wrong with that module, I’d have such difficulty following wires because they’re all the same two colors.
Could be a non-issue for your team, I don’t know, but that would bother me.
https://drive.google.com/file/d/0B8zgCWCB5RBYVUFSd2lWTTh5V3M/view?usp=sharing
We did something very similar this year. We mounted the RoboRio, PDP, PCM, VRM, and Pneumatic gauges and regulators on the top and motor controllers on the bottom so that the module sandwiched the wires. The result was a very clean and elegant control panel that we were able to easily remove in a couple of minutes.
A couple problems with it:
Perhaps it’s not the best place to put pneumatics because getting a leak in the middle of the panel is a nightmare.
Also any time you needed to work on the wiring, you have to disassemble the thing which can get annoying after the forty-eighth time.
One of the more efficient modular electronics packages I’ve seen - this might make me rethink using them. When my teams have done them in the past, they’ve added far too much weight to be worth it.
One small suggestion - it might be worth adding a fan or two to make sure you’re getting enough air circulation to keep the motor controllers cool. Assuming you’re using the newer, passively cooled models, this isn’t as much of an issue as it once was, but it’s still recommended to make sure there’s enough air flow for the convective cooling to work.
Obviously we do not know the game rules for this year, but 1 rule that probably won’t change is that all breakers and the PDP must be easily visible to inspectors. In addition their are diagnostic lights on the PDP that you would not have access too.
I don’t see your Circuit breaker either, which needs to be accessible.
The construction standards would have to be really good. Otherwise, your team will be taking that apart multiple times to find and fix loose connections or crossed wires.
It would also be best to install and wire out extra motor controllers so they can be just connected to the motors. Of course, these extra motor controllers would have to be pre-tested to make sure they are connected correctly so that they will work when needed.
Update on the board. 3 of the corners are pins that pull out easily for inspection. The entire top layer is able to swivel on the remaining pin allowing for the top and bottom layer to be shown. The wires are labled with different colors to easily trace back. And a fan will be added to help cool the motor controllers. The main breaker will be on the robots superstructure to be easily accessed.
Head of Electrical
Side note laser cutting polycarbonate does not work very well with a near infrared laser cutter. The cutter burned the polycarbonate and did not leave clean cuts.
Do you intend to swing the upper board aside while all the wires to it are connected? If so, you will have to route those wires properly to make this possible. Hinged/moving electrical panels are tricky to do well.
Will the remaining screw/bolt and the corner of the upper panel take the weight of all the components and the attached wires?
It would be better to label your wire pairs and cables (PWM, CAN, sensor) at both ends. Colour coding can be used to identify wires and groups of wires with similar functions.
Yes the hinging will happen while the wires are connected. It is hard to see but there is a L shaped hole that allows for the wires to pass through. When the top board rotates on the bolt the L shape allows for extra room for the wires to shift.
As for the color coding goes the 3 wires currently that are the same are the white wires. on both ends of the wires are small colored zip ties. ex(PCM has a blue zip tie on both ends and the VRM has green zip ties)
Did you remember to use 12 gauge wire? :rolleyes:
Yes. We also remembered who to pick for alliace selections ::rtm::
Putting all those talons in there can be a thermal problem. I think that it is too tight for a fan to be effective. A FIRST version of an easy bake oven.
You will still have to route the wires so they do not impede the motion of the upper board. Often it takes the form of a loop.
You may want to get a label maker such as the one linked below. The wiring then becomes self documenting. They have a deal where you buy a bunch of labels and get the machine “for free”. We are now using a similar machine for the equipment we build at work.
http://www.labelcity.com/Rhino-4200-Carry-Case-Kit-1835374.html
http://www.labelcity.com/Free-Dymo-Label-Printer-with-Label-Purchase.html
So we finished putting the whole thing togather and it works very nicely as far as rotating and we do have a label maker.
Just chiming in to let you know how much I laughed at the Rick McCallum joke in the title. A+.
Everything that Jimmy has said and more.
Inspectors need to see the breakers, the wires that they feed and the color codes used. The terminals must be rated for current that exceeds the protected current for that branch (i.e. rated for 40 amps minimum when branch is protected by a 40 amp breaker). You may need to show data for those terminals during inspection.
From 2015 rules (unlikely to change much)
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.
I agree with Gary that heat is a bad thing especially when under the RoboRio.
I’ll raise again. Hidden wires are hidden problems. Unless your wires are always perfect every time (and with teenagers, really?), making wires harder to trace will cost you time in troubleshooting when you most need it (e.g. between matches that are only a few minutes apart). Even though we had no power wire faults on last year’s robot, and no faults at all at competition (though we did have a few signal level issues on the build site), we still plan to route wires cleanly and visibly upon removal of a couple of clip-on cable run covers.
I am wondering, do the breakers need to be visible just for inspection or for the length of the tournament? Also The same question about the PDP indicator lights. As far as the 2 layer panel is it meant that positive wires should be red and ground should be black, or do the wires have to each be different colors (ex. VRM to PDP is yellow and black, PCM to PDP is red and black?
For inspection, which may happen at any time. Inspectors can reinspect any team at any time for any reason (though most will only inspect for a good reason, like someone asking them if some new addition is legal).
However, having the PDP lights visible can be very useful to event staff–and your team members–trying to figure out why your robot isn’t working. It’s also very useful to not have to tear apart the electrical panel to see the lights.
As far as the 2 layer panel is it meant that positive wires should be red and ground should be black, or do the wires have to each be different colors (ex. VRM to PDP is yellow and black, PCM to PDP is red and black?
There is no specific instruction that all wires have a certain coloring–but follow the Manual on those wires. See Al’s post. Also, it’ll make inspection easier if only two colors are used (means your inspector doesn’t have to read the rule to verify that your semi-random color is legal)