pic: XBot Electronics Day 2



We are working hard this season, trying to get all the basics done early. Kids finished the electronics board today - well at least for the first 4 motors :slight_smile:

Nice looking board there.

One question, the 90 degree connectors for the DB-9 cables (tether, radio, programming), where did you find those. Look very useful, thanks.

-Chuck

stop using blue and white wires. most of the inspectors will just give you greif

Inspectors should not “give you grief” for using blue and white wires as shown here. (Inspectors are volunteers and volunteers are at the event to help teams, not to give them grief.) Per <R54> blue is OK for common circuits and white is OK for 12V. However, the use of these colors is not very common in FIRST, so you should be prepared to show your inspector the rule in case he/she has not seen this before.

[quote=2008 FRC Manual, Section 8 The Robot, <R54>]All wires distributing power with a constant polarity (i.e., except for relay module, speed controller, or sensor outputs) shall be color-coded as follows:
• Use red, white, or brown wire for +12 Vdc and +5 Vdc connections.
• Use black or blue wire for common (-) connections.[/quote]

Might want to check the rules again, per <R50> “All circuit breaker distribution panels must be directly connected to the power distribution block”, so that white wire from the Maxi Block to the other fuse block might need to be moved. This would require adding another red section to the power distribution block also.

We used blue and white last year with no problem at three events. I hope that doesn’t change :wink: Have you seen/experienced any inconveniences with the alternate color wires?

Here are the connectors. They are a bit heavy, but with how close everything ended up on the board, they will probably come in handy.


Make sure you get the right “exit” so the connector is going the right way :wink:

Yeah, I think this was under discussion. The board was wired this way because of the functional convenience of it. Maybe the kids will strip an interior portion of the wire and have a single piece all the way through :slight_smile: Adding the other wire will be trivial when necessary.

Might want to rereread <R50>…it’s pretty obvious to me that the intent of the rule is that you connect each load wire directly to the PDB, not to any other device. “No intermediate connections are permitted”.

one of the reasons for that was That I was your Robot inspector at championship. i know its no big deal what color your wires are as long as you diferinate between + and -.

Having been a robot inspector. i’ve seen how the typical voulinteer inspector is generaly given an idea about how to inspect robots and then tries to go through the list to the best off their ability. and they tend to ruin a teams day when they don’t pass you for somthing silly like that

Yes your absolutely right be ready with the rule in your hand.
Im not saying that inspectors should “give you grief” . im saying that you will have some that will

On the topic of different colored electronics, why does FIRST give us the wrong color Anderson Connectors for our mainbattery plugs? Red signals 24v. Yellow is for 12v. Anyone happen to know?

It’s a donation. It pretty much means we get what they are willing to give. :slight_smile:

Do you know which standard that comes from, because I’m not aware of any such convention? Anderson makes both red and yellow SB50 connectors designed for 6 AWG and rated for 600 V (for insulation purposes). Their datasheet doesn’t suggest a colour code.

I was thinking the same thing. I couldn’t find a list on the Anderson site, but there was a list here http://en.wikipedia.org/wiki/DC_connector that suggests that at least Anderson has their own color coding recommendations.

Maybe you can inspect us again. The kids enjoyed that inspection more than any other.

For the record…
<R54> All wires distributing power with a constant polarity (i.e., except for relay module, speed
controller, or sensor outputs) shall be color-coded as follows:
• Use red, white, or brown wire for +12 Vdc and +5 Vdc connections.
• Use black or blue wire for common (-) connections.

AND

<R50> The 12V battery, the main 120-amp circuit breaker, the power distribution block, and circuit
breaker distribution panels shall be connected as shown in the 2008 Power Distribution
Diagram. In particular:

• All circuit breaker distribution panels must be connected directly to the power
distribution block. No intermediate connections are permitted.

Not only does daisy chaining the power violate rules it is a bad idea, causing the voltage drop from your high current loads to lower the available voltage to the RC. Split your high current loads when possible.
As to the color code, my personal position is to use the color codes normally used in your area so that your students become accustomed to industry standards. Although brown and blue are european standards they are not in this country.
All teams should take note of the placement of the high current components such that #6 wire runs are short and direct.

Nice board. Simple and effective.

Please people read the post before writing your junk it is really annoying to read things twice or more. Like in this post about the PDB it has been said please no more i think they get the point.