Electrical connectors on control system items

[GeeTwo]

While power poles don't natively latch, they do natively restore a temporarily loosened connection. Retention is not through friction, but through the spring force of the two contacts. If the contacts are properly assembled, and the cable is not under tension, the contact won't just vibrate loose; it would take a shock load in which the connector's inertia provides the breaking force. If you partially disengage a power pole and release it (or don't engage fully on insertion), the spring contacts will [re-]complete the engagement for you.

[caume]

I'd love a self crimping .1in connector, also possibly a latching .1in connector.

Anderson Powerpoles are a gift from god if you asked me. Nothing should replace them.

[Peter Johnson]

Originally Posted by caume

I'd love a self crimping .1in connector, also possibly a latching .1in connector.

There are latching, polarized (LP) 0.1in connectors. However, they aren't self-crimping, but practice helps! Also, I've found the Hansen LP housings and inserts easier to put together than the standard ones for some reason (I can just crimp with the Hansen cheap crimper and they slide right in most of the time), although I'm sure the correct solution is to buy the "real" crimper ($$$).

[Alan Anderson]

Originally Posted by caume

I'd love a self crimping .1in connector, also possibly a latching .1in connector.

The 3M Link connectors sound like what you want. They were in the 2014 Kit of Parts.

http://www.digikey.com/product-detai...000-ND/1238395

[marshall]

Originally Posted by Alan Anderson

The 3M Link connectors sound like what you want. They were in the 2014 Kit of Parts.

http://www.digikey.com/product-detai...000-ND/1238395

I wish they were a bit smaller...

[Ben Wolsieffer]

Originally Posted by Alan Anderson

The 3M Link connectors sound like what you want. They were in the 2014 Kit of Parts.

http://www.digikey.com/product-detai...000-ND/1238395

We used these as CAN connectors and they worked well.

[GeeTwo]

Originally Posted by caume

I'd love a self crimping .1in connector, also possibly a latching .1in connector.

Anderson Powerpoles are a gift from god if you asked me. Nothing should replace them.

What do you mean by "self crimping"? Wow. Damm.

Again, I'd like to note that while APPs are internal standards of many FRC teams, they are in no way (to date) an FRC-endorsed standard. That said, if Talon SRXs or Victor SPs were [additionally/alternately] available COTS with APPs on the output (green and white) wires, leaving the red and black as stripped wire ends, 3946 would be sure to buy a bunch expecting to step around the difference between R13 [fabrication schedule, in particular R13-D] and R18 [Witholding Allowance rules] for 2016 and similar rules in recent years.

[Peter Johnson]

Originally Posted by GeeTwo

That said, if Talon SRXs or Victor SPs were [additionally/alternately] available COTS with APPs on the output (green and white) wires, leaving the red and black as stripped wire ends, 3946 would be sure to buy a bunch expecting to step around the difference between R13 [fabrication schedule, in particular R13-D] and R18 [Witholding Allowance rules] for 2016 and similar rules in recent years.

I would think an easier solution would be for FIRST to fix R18 to add an exception similar to R13-D and R18-A thru -C, and such a fix would be consistent with what appears to be the intent of R13 (reuse of motor controllers from year to year). Excepting that, you could put a couple of spare motor controllers in the bag with the robot so they aren't covered by R18.

With regards to connectors on Talon SRXs, my team puts APPs on both ends of the motor controllers and populates the PDP with short stubs to APPs. Yes, it adds a tiny amount of resistive loss, but it also makes it much much faster to swap and/or disconnect (we never have to pull a breaker!).

[Mike9966]

Hi all, Just had to throw my 2¢ in on this one.

As someone said, the powerpoles are a gift from God! lol, True, you do have to shell out $40 for a nice crimper, and you do have to train the students on how to use it, but once this is done, life is good.
Yes, do zip tie them if you are worried about them separating, one small one laterally does the trick.
We put these on all our SRX's pretty much straight away when they come in.

Someone mentioned confusing the input and output. Our method is to use Red/Black on the input (anything that's always hot), and Pink/Black on the control side. Motors get Pink/Black too, that way you should only ever see pink to pink, and red to red. Pretty simple.

I don't like deans due to the exposed contacts, and soldering necessary.

We use latching polarized (like the Hansen hobbies ones) that we buy from Digikey. Again, when the SRX's come in we put one male, and one female on each unit. I like to use the 3 pin ones so the connections can be used for either can or PWM.

The Coaxial barrel jacks are awful and should be banned! True, you can zip tie them down, but what a pain, just bad all the way around.

The worst connectors bar none though are the stick pin headers on the roborio. There is nothing to tie things down with, one has to add sticky squares and so on, and even then we had one or two pop out this year after doing the dukes of hazard thing over the chevys. Grin.

I'm not in favor of spring cage clamps as in the PDP and elsewhere, screw cage clamps would be my preference.
Space, and student strength are the main problems here.

Faston (spade, aka bladed, etc) I don't like as the nylon shrouded females frequently aren't pushed properly onto the male side. The male blade ends up between the plastic and the connector. (and then falls off).

Don't like JST, too small and fragile.

Screw terminals are ok, we used them on Jag's for years, but I'd prefer a built in power pole connector, not the flying leads on the SRX.

Mostly one has to simply do a good job with any of these and they will serve you well if they are used for what they are meant for.

One final thought, use good wire! Not something stiff as a board, or the wrong size!

Have a good one, and don't forget to pull test EVERYTHING.

Mike

[jwfoss]

Does anyone have any experience with the Traxxas Connectors?

[Greg Needel]

Originally Posted by jwfoss

Does anyone have any experience with the Traxxas Connectors?

patented proprietary connectors :-(


One of the reasons I like the XT series of connectors as a new option is that they are completely open so there are lots of low cost options and carry some of the same advantages of anderson (compact high current, polarized connector)

When REV is looking at options for our products the cost of things like connectors is really heavy on our minds since we are trying to help teams do more with less $. Take Anderson Power poles for example, we could build a version of the SPARK or any of our other new products with integrated Anderson (similar to what modern robotics did for FTC). The issue is that because Anderson has IP on those connectors they cost us .32 for each terminal and .20 for each plastic cover. So on a product like the spark there would be 2.08 in materials cost just for the connectors, not counting the labor of inserting through hole components and installing the plastics. We would also feel obligated to provide 4 mating connectors in the box, so teams who have never used them before have some to start with (customer experience), so add another ~1.50.

So at the end of the day, is it worth it to teams to add a minimum of 3.58 to every single product just so they have have a slightly better connector?

That's the reason for this thread, we are trying to make these decisions with the team experience in mind, both in terms of cost and performance and it is always a difficult trade off.

*we used screw terminals on the SPARK (and likely some future projects), because they are easy to source, cost ~.15 each in bulk, and ring terminals can be found at every home depot, lowes, radio shack, etc for pennies each.

[RyanN]

I've been involved with FRC electrical since 2005, so I feel I have some experience here.

Greg, I think screw terminals are fine. My only nit picky thing with the Sparks was the PWM retention. I really like how the old Victor 888s did it with a full enclosure around the connector; however, that comes at a cost of having straight PWM pins that slip into place.

I'll be the first to admit that our robot's electrical wasn't great this year. It worked... but the wires did jar around with the defenses and we have had the PWM cables get tugged. We found that the PWM cables going to our Sparks bent. If it was a straight tunnel case, I don't think that would have happened.

I'd say the PWM cables are adequate because... well, you have to have PWM cables for the RoboRIO as well.

Now, for the Spark 2. Can we can some CAN? I like the Weidmuller connectors, but at the same time, I don't mind screw terminals. I think you could pull off a full CAN connector that binds the wires between two plates that would achieve the daisy-chain topology of CAN. I'd very easily pay $10 more for CAN integration, and I don't necessarily care about all the crazy features the SRX has. You'll have me happy with speed, direction, brake/coast, and limit switch control and feedback. I don't care about current (I can get that from the PDB, I don't care about voltage control, current control, motion profiles, etc...) I do care about reducing the number of wires on my robot and making it more reliable.

[mman1506]

Originally Posted by jwfoss

Does anyone have any experience with the Traxxas Connectors?

Hobbyists usually consider Traxxas connectors inferior to deans or XT.

[taichichuan]

I'd have to second the comments about hating JST connectors. While the retention is fairly good, these connectors are nearly impossible to fabricate reliably.

The T-plug connectors are fine for singleton connection. But, we frequently find ourselves with bundles of cables that the APPs allow us to gang together and key the connection in such a way that the connections can't be mis-connected. Yes, you really need the specialized crimper. But it's less than $50 and most other types of connectors (like the .1" PWM connectors), regardless of the type, require a specialized crimper to do it right.

The XT60 connectors are like the T-plug connectors. Great for singleton connections. The mechanical connection seems more robust to me over the T-plug connections. But, these connectors look like they need a special crimp tool or need to be soldered. So, I don't really see that these are any better than what we have already.

HTH,

Mike

[sraque]

I don't favor JST connectors. They are fine connectors, I don't hate them as others seem to, but they are difficult for a team to fabricate because the crimpers made for them are outrageously expensive. You can find generic crimpers, but they require figuring out the right size to crimp both the conductor and insulation. I would not want to deal with any more small JST, Molex, etc. connectors than we already have to for some of the sensors we use.

I don't favor connectors that require soldering either. We produce crimped connections more reliably and quickly, and they hold well under abuse when the crimp is done well.

We love the Anderson Powerpoles and the (cheaper) version of the Hansen Hobbies Molex connectors from Digikey.