Electrical CheckList

[McGurky]

Well after learning from this year that quickly checking over electronics is NOT a good Idea. I was thinking that I should make a checklist for whomever is inspecting the electronics. Do you guys have Ideas on what to include on this checklist?

Here is a start

All wire gauges are correct
correct breakers are in place
check all power wires for any frays
check all wires going to and from the C-Rio for frays and shorts
All debris is free of the electronics "area"
everything is grounded correctly
Battery terminals are shielded (tape or heat shrink)

Digital SideCard

All pwm are in the right orientation
correct jumpers used
all connectors are correctly placed and in the right orientation
no loose metal/debris around/in the Digital SideCar...

This is just a start so please any help will be appreciated... I will publish the final list when it is completed

[rtfgnow]

Is this for maintence between matches? I would mainly check that the pwm and power wires are connected. Breakers and wire guages are rearely effected during a match.

If you are more geared towards a pre-inspection lookover, than be sure that the rules laid down about wire gauge and breaker sizes are followed, check that batteries are taped at the terminals and that you are not grounded into the robot, and that there are no jumpers on the sidecar that shouldn't be.

These are very general instructions. Making a checklist and bringing it to competition can be helpful.

[rsisk]

Simple question I hope, how do you check that everything is grounded correctly?

[rtfgnow]

Originally Posted by rsisk

Simple question I hope, how do you check that everything is grounded correctly?

Take a multimeter set to continuity and touch one end to the negative of the power distribution board and the other end to the negative of your jaguars, spikes, victors, etc. If it beeps you are grounded correctly, next repeat with the first end touching a piece of metal on your robot, it should not beep this time.

[EricVanWyk]

I like to divide checklists like this into "stuff I have to do before applying power" and "stuff I'll find faster by watching it fail".

For example: errors in the high power wiring can result in damage, but forgetting a jumper on the DSC will just prevent that servo from running.

[McGurky]

This would be more of a chacklist that every the electronics is tampered with or worked on, to run through this list to be sure that nothing will get fried on powerup

[Joe Ross]

The inspection checklist (available on the competition manual page is a good place to start.

The best way to make sure you don't have problems in the middle of the season is make sure everything is designed well at the beginning. The Electrical Design presentation from the 2005 championship workshops has many good tips (some parts are specific to IFI, but not much).

For most of the items you mentioned, there are a lot of things that can be done ahead of time to make those problems less likely to occur. A checklist is helpful, but thinking about how to avoid those problems is even better. I've given some examples below in bold. I also agree with Eric that many things are easier detected by testing then by inspection, so as long as there aren't safety issues, a pre-match check will be much faster for many things.

Originally Posted by McGurky

All wire gauges are correct
Does everyone working on the electronics know the correct wire gauge, or where to find them.
correct breakers are in place
easier to find by test
check all power wires for any frays
Check wires for frays before installing them. Route wire well, and make sure it's tied down, and it won't develop frays
check all wires going to and from the C-Rio for frays and shorts
see above
All debris is free of the electronics "area"
When possible, all debris generating activities should be done away from the robot. If not possible, the rest of the robot should be shielded as much as possible (we use butcher paper or newspaper) and the robot vacuumed afterwords. Most of the problems I've seen have either been a huge amount of debris (no precautions taken) or such a small piece that a casual inspection wouldn't have found it.
everything is grounded correctly
Training
Battery terminals are shielded (tape or heat shrink)
If battery terminals are installed well, it shouldn't be necessary to remove them or the insulation

Digital SideCard

All pwm are in the right orientation
easier to find by test
correct jumpers used
easier to find by test
all connectors are correctly placed and in the right orientation
since the power connectors are keyed, you don't have to worry about them after the first time the cable was made. Other connectors can be verified by test
no loose metal/debris around/in the Digital SideCar
see above

[Al Skierkiewicz]

Before we begin, there is no ground on the robot. There is however, a battery return, generally all black wiring is tied to the battery return. The CRIO has this lead tied to it's case for grounding in electrically noisey environments and for safety grounding where required by local electrical codes.
High on my list is to make sure no wires have pulled out. This includes PWM cables but all wiring should be snug and survive a wiggle/pull test. Check that the 50 amp connectors on the battery and robot are clean and not scratched. Check that the #6 wires on both the batteries and the Power Distro are snug and do not move when you wiggle the wire. Check that all hardware is tight on the controllers. Check that the wireless bridge/radio power is inserted. Check that the RJ45 plug is in place and snug. Check that all breakers are in place and snug.
As soon as possible after returning from the field, check for hot components like motors, breakers, wiring and controllers. Use your nose and smell for burned motors or other electrical failures. Replace as needed and then retest operation.
After everything seems correct, have someone else give the robot a visual check. This could be a mechanical student. When everything seems fine, do a power up test with the wheels off the floor and all hands away from the robot. When everything checks out, replace the battery with a known good battery.
Then relax you are ready to go for the next match.