Electrical connectors on control system items

[Greg Needel]

Hey All,
We have been working on a bunch of new products for upcoming seasons and wanted to get the community's opinion on an internal debate we have been having at REV.

In the current control system there are numerous styles of electrical connectors, each one has it's own advantages and disadvantages (cost, size, current carrying ability, easy of installation, robustness, etc) and there have been a few "standards" that have appeared over the years. While we are still in the phases of working on new projects I always think it is a good idea to question previous assumptions rather than just assume they are correct.

Here are all of the connectors that are commonly used

• .1inch headers (PWM) - used for all signals to the roboRIO & motor controllers - minimal retention but cheap
  
• Weidmuller wire-to-board - Used for CAN connections & module connections - expensive, good retention, requires precise wire striping
  
• Wago - Used for the Power distribution board - Expensive, good for high current, very reliable
  
• Screw terminals - Used on SPARK motor controllers & others - low cost, good retention, small, screws can strip/get lost
  
• Spade terminals - Used on the Spike relay and wire to wire connections - cheap
  
• Anderson Powerpole - main battery connector & commonly wire to wire connections - medium price, good quick release, hard to crimp without special tool
  
• IDC connectors - used for MXP, SPI, & talon motor controllers
  
• USB - Used on the roboRIO & other places
  
• Barrel jack - used on the radio
  
• RJ45 (ethernet) - Used on the radio & roboRIO
  
• RJ11 - used on Jaguar motor controller

Here are some new connectors I would like opinions on.

JST connectors (PH series for example ) http://www.jst-mfg.com/product/detail_e.php?series=199 - As a replacement for PWM cables
XT Connectors (30 or 45) https://www.amazon.com/OOOUSE-XT60-C.../dp/B005FAPYXS instead of power poles or wagos
Deans connectors - https://www.amazon.com/dp/B00S7G4A14/ instead of power poles or wagos



So you tell us, What frustrates you or makes you happy about the existing connectors? What connectors do you hate and which ones do you like.

We are also open to other suggestions let your opinions fly.

[Christopher149]

The screw connector for powering the roboRIO (and previously cRIO). I don't know if we were using it wrong, but especially on the cRIO, the wires would too frequently come out or be loose. I don't think we've had an issue on the roboRIO, though.

[randantor]

I'm really not a fan of XT-series connectors, and solder-type connectors in general. It's much harder to judge the quality of a solder joint than a crimped connection.

In my experience using these connectors with stranded wire causes solder to wick up into the wire a bit, causing the wire around the connection to become brittle and prone to have issues if not given adequate strain relief. Soldering in general is much more error-prone and time consuming than crimping a connection with the proper tool.

[FrisbeeFunTime]

I've never had any experience with the jst connectors or the xt connectors but I would imagine the xt connectors to be pretty good. The deans connectors I have had experience with before. They are a bit of a pain to solder to but they are done correctly they hold well and when plugged together they are almost impossible to take apart. They also take up a small footprint compared to other connectors which is always a nice thing.

[Tom Line]

Originally Posted by FrisbeeFunTime

I've never had any experience with the jst connectors or the xt connectors but I would imagine the xt connectors to be pretty good. The deans connectors I have had experience with before. They are a bit of a pain to solder to but they are done correctly they hold well and when plugged together they are almost impossible to take apart. They also take up a small footprint compared to other connectors which is always a nice thing.

I absolutely hate deans connectors. My kids all participate in RC (boats and cars). And these things are the #1 reason I see cars dead on the track. I've gotten packages of things where no matter how hot you get it or how careful you are they simply will not pass a pull test after you solder them. I've taken said packages to the hobby stores and they tried one and threw the rest away, and opened a new package.

I will stick with crimp style connectors. In marine applications, soldered connections are highly frowned upon by the certification organization because they are uncertain and are a brittle failure point in high vibration environments.

[asid61]

".1inch headers (PWM) - used for all signals to the roboRIO & motor controllers - minimal retention but cheap"
I like the Hansen Hobbies latching connectors way more; the peace of mind and ease of use is great. Not too expensive either. That being said PWMs work fine for me too.

"Anderson Powerpole - main battery connector & commonly wire to wire connections - medium price, good quick release, hard to crimp without special tool"
I love how you can stack them into bunches, but they are very hard to put together and remove this way, especially if a single component in a bundle fails.

"RJ45 (ethernet) - Used on the radio & roboRIO"
I've thought about using these for non-ethernet applications due to the availability of crimpers, crimps, and cheap cable cost of many different lengths from digikey. I have used a few of these in non-FRC non-ethernet applications, and they've performed admirably.

[cad321]

Originally Posted by asid61

I like the Hansen Hobbies latching connectors way more; the peace of mind and ease of use is great. Not too expensive either. That being said PWMs work fine for me too.

I had not seen these before. They look like a great alternative to pwm cables. However I don't see much of a need for them unless they were to become a standard connector on most FRC products. Great if you are joining 2 cables (such as at a joint or turret for quick removal). However if you dont have the latching socket on say the roborio, it just becomes a standard PWM with an extra piece of plastic.

I would love to see something like this become a standard.

[Knufire]

I really like the connectors on the US Digital S4/E4 series encoders. Browsing around on their website, it looks like it's a 1.25mm pitch Molex PicoBlade connector.

https://youtu.be/0bRyezC_P0M?t=141

The big thing I enjoy about them are the friction locks, they feel much more secure than standard 0.1 header connectors. I wouldn't mind a bigger pitch than 1.25mm though for FRC use though.

[adciv]

Originally Posted by Greg Needel

So you tell us, What frustrates you or makes you happy about the existing connectors? What connectors do you hate and which ones do you like.

I *HATE* JST connectors. You can't make them yourselves, they use 24 AWG wire (prone to breaking), and you have to tug on the wire to get them to disconnect (more damage potential). I'm trying to find an alternative to US Digital encoders solely because they use connectors with the same issues.

As to the others, I don't like soldering when I can avoid it. I much prefer crimping as it is easier to assemble & maintain. I prefer the Anderson power poles over what are shown for a number of reasons. The individual parts aren't polarized (but I can polarize them by how they are assembled). I don't have to worry about keeping M & F components in stock. Can be assembled into larger blocks.

Originally Posted by sanddrag

.1inch headers (PWM) - annoying and really time consuming to crimp and/or solder. All the cheap tools suck. I wouldn't be opposed to something better (or maybe I just own the wrong tools).

We use the Hansen hobbies crimper and it works well (~$40).

[arichman1257]

This is just my opinion on the connectors mentioned.

.1 inch headers (PWM) - As long as the pins on the roboRIO or on the male connector don't bend they're great to use. The cables themselves are somewhat bothersome when they're not long enough to reach because the connectors don't provide an easy way to connect wire to wire without being prone to disconnecting.

Weidmuller - Probably my favorite connector that is used for the small wires. They are easy to press (I have been known to just use my finger in a pinch) and hold the wire well when they have been used properly.

Wago - They work very well for large wires. When the PDP isn't in a convenient position they can be hard to work with if not given the proper care. I don't really have a problem with them but I know that some people do.

Screw terminals - Annoying when they're not placed well and sometimes the screw is dropped. But otherwise reliable if used correctly.

Spade terminals - I don't like them. They always break on me.

Anderson Powerpole -My favorite way to connect wires to each other hands down. (When current draw allows)

IDC connectors - They work well enough. Good way to join many wires to pins.

USB - I haven't really had them in use on an FRC robot enough to give an opinion.

Barrel jack - They pull out when tugged on and should be secured with a ziptie or something like that. but if theyare not abused (pulled on) they work well

RJ45/RJ11 - They're great until the little clip on them breaks

[Coach Seb]

I appreciate all the post and comments. Wiring, connectors and plugs is on our list of improvement this year.

Is there a web page or document that describes the most used wires type and connectors used in FRC and different options that are available? even a poster to use as a reference? does your team have a document that describe the standard you are using?

Any info would be appreciated.

[Ernst]

Originally Posted by Knufire

I really like the connectors on the US Digital S4/E4 series encoders. Browsing around on their website, it looks like it's a 1.25mm pitch Molex PicoBlade connector.

https://youtu.be/0bRyezC_P0M?t=141

The big thing I enjoy about them are the friction locks, they feel much more secure than standard 0.1 header connectors. I wouldn't mind a bigger pitch than 1.25mm though for FRC use though.

Huh, I've always hated those. The attached wires were always a pain and usually messy, plus unplugging them didn't always go well.

We started using some custom .1in connectors this year for different sensors, like a 5-pin one for Grayhill encoders and some 2-pin ones. Those worked well when done correctly, but our quality control wasn't great, and a few connectors made it onto the robot that might have given us some intermittent signals. We're learning, though, and I think we'll go back to them and use more next year.

We also had some trouble with several Weidmuller connectors. No matter how many times we tried with different wires that were the correct gauge and stripped the correct length, a few connectors just wouldn't work. Others were perfect and lasted all season. We picked up some ferrules to try to address that next year.

The 3-pin connectors are decent. We wound up taping and zip-tying a lot together, though, so we might pick up some VEX EDR connector clips. I'm a bit disappointed that the RoboRIO has male pins. We had one of those connectors come loose despite us using 3D printed cable management/spacing inserts. Other than a giant 10-connector female-to-female converter that plugs into all of them and reinforces everything, I don't really know how to address that.

I haven't personally used the XT or Deans connectors, but, given the option, I would stick with Powerpoles. They can clip together to make large plugs, they're easy to lock together, and we have tons of them stockpiled.

[sanddrag]

As the teacher on a team that prides itself on clean wiring, I like this thread and feel inclined to comment.

.1inch headers (PWM) - annoying and really time consuming to crimp and/or solder. All the cheap tools suck. I wouldn't be opposed to something better (or maybe I just own the wrong tools).

Weidmuller wire-to-board - has been fine
Wago - Can be tough to access in tight spaces. Need to plan for tool access in the design and assembly processes. The big ones on the PDB are fine. Small ones can be annoying, but workable.
Screw terminals - Not opposed to these in the right application, but the problem with Victors in the past was finding a non-insulated flanged spade terminal for a #12 wire and s #6 screw that was narrow enough in width to properly fit the Victor.
Spade terminals - Works well, fast crimping, can be tough to get off sometimes.
Anderson Powerpole - These work very well. Crimping is not an issue for us. I really wish there was a 4AWG SB50 terminal though. We also sometimes have issues with the PP30/45 and SB/50 series getting the terminal all the way in after crimping if the insulation is large or the crimp is slightly malformed. But once you get the terminals over the clip, it's flawless. It's a training issue more than anything.
IDC connectors - seem fine I guess
USB - Haven't used them in an FRC sense.
Barrel jack - Always concerned about losing contact. We put a lot of thought and effort into properly retaining this connector so it cannot come out.
RJ45 (ethernet) - We do not use off the shelf pre-made cables, to eliminate excessive length. We've had some issues properly crimping these. Also, the clips are fragile, and if there's a stiff boot on it, you risk breaking the port itself if the user does not have the finger strength to fully depress the boot before pulling the cable out. So for that reason, I'm weary.
RJ11 - Similar to what I mentioned above, but I haven't used RJ11s specifically.

Here are some new connectors I would like opinions on.

JST connectors (PH series for example ) - Seems plausible. I'd need to see and try the terminals and crimper.
XT connectors - Never. Short circuit risk on the solder cups and just the fact that you can't crimp it.
Deans connectors - Never. The exposed terminals on an unplugged connection are a serious short circuit hazard for teams who don't know what they're doing and install that half of the connector to the wrong side of the circuit. PowerPoles do not have a male or female side.

[pilleya]

For me I value the ability to combine connectors into one main block and the ability to easily differentiate between positive and negative connectors. The power-poles also come standard with quite a few different colours and accessories such as retention pins.

For the 2016 season, we built a turret mounted shooting mechanism. We had 5 motors on the shooting mechanism, with 3 CAN Talon SRX’s mounted onto the rotating component with all sensors going into the SRX’s via CAN. We utilised Anderson Powerpoles(45amp) because they enabled us to join the plugs into one central block, including the CAN via green and yellow powerpoles. We were able to unbolt our entire shooting mechanism and simply unplug the main plug in order to quickly switch out our turret mechanism with our spare.

I don’t believe this block mounting style is possible with the XT connectors or the Deans Connectors.

[pilleya]

Originally Posted by sanddrag

I really wish there was a 4AWG SB50 .

If you are wanting to use 4AWG or larger for battery cables, it is legal to utilise a SB120 connector,

Originally Posted by FRC Game Manual 2016

Any size a single pair of Anderson Power Products (or APP) 2-pole SB type connectors