Connector Advice
May 30, 2013 8:24 AM Subscribe
What general purpose signal wire connectors do you guys use?
In-particular strain gauge 4-20mA pressure transducers. I get the mil-style (PT06A-10-6S) for the termination at the PT, but I have found that I really dislike this style of connector for extension cables. For one the two ends of the connector do not mate without some kind of panel mount union. Also connecting two cables together shouldn't cost ~$60 in connecting parts.
I've been using the small red bullet connectors, but am unsatisfied with my crimps sometimes.
I've looked into some other circular style connectors, but I dislike soldering these together (error prone). Also fixing and troubleshooting these connections in the field can be a real pain. The connector body obscures the connections and a multimeter is almost always required for troubleshooting. Repair requires a soldering iron which is also a problem for field work.
I've really found that I like Molex style connectors. These are crimp based, have some strain relief, and can be visually inspected to ensure that the terminations are correct. My understanding of the target applications for these devices is to supply DC level voltage to loads that draw ~<5A (normally). In my application the current levels are far lower, but I'm just unsure if using a Molex style connector is the right path. Also, my cabeling is shielded and it looks like a Molex connector will break the shielding (I currently pass it through on a bullet connector which doesn't seem to be much better). Noise isn't really a problem though. I tend to sample these signals at a rate of about 1 kS/s and average the oversampled data down to about 10 S/s. When comparing the readings of my pressure transducers against a known calibrated standard, the results are consistent with the manufacturing specifications so I don't think the fact that my connectors aren't shielding the connection is an issue but maybe you have a different opinion about that.
Ideally I would like to have a connector standard for extensions of these pressure transducers. The ends of a cable should mate with one another, be easy to assemble, don't present excessive noise issues, and work fine for applications with "rise time" requirements ~<1MHz (ideally). Also, I need 5 position and 4 position connectors. Even better if buying pre-fab cables with these ends were readily available...but I will need to do some crimping anyway.
Thank you for your input!
In-particular strain gauge 4-20mA pressure transducers. I get the mil-style (PT06A-10-6S) for the termination at the PT, but I have found that I really dislike this style of connector for extension cables. For one the two ends of the connector do not mate without some kind of panel mount union. Also connecting two cables together shouldn't cost ~$60 in connecting parts.
I've been using the small red bullet connectors, but am unsatisfied with my crimps sometimes.
I've looked into some other circular style connectors, but I dislike soldering these together (error prone). Also fixing and troubleshooting these connections in the field can be a real pain. The connector body obscures the connections and a multimeter is almost always required for troubleshooting. Repair requires a soldering iron which is also a problem for field work.
I've really found that I like Molex style connectors. These are crimp based, have some strain relief, and can be visually inspected to ensure that the terminations are correct. My understanding of the target applications for these devices is to supply DC level voltage to loads that draw ~<5A (normally). In my application the current levels are far lower, but I'm just unsure if using a Molex style connector is the right path. Also, my cabeling is shielded and it looks like a Molex connector will break the shielding (I currently pass it through on a bullet connector which doesn't seem to be much better). Noise isn't really a problem though. I tend to sample these signals at a rate of about 1 kS/s and average the oversampled data down to about 10 S/s. When comparing the readings of my pressure transducers against a known calibrated standard, the results are consistent with the manufacturing specifications so I don't think the fact that my connectors aren't shielding the connection is an issue but maybe you have a different opinion about that.
Ideally I would like to have a connector standard for extensions of these pressure transducers. The ends of a cable should mate with one another, be easy to assemble, don't present excessive noise issues, and work fine for applications with "rise time" requirements ~<1MHz (ideally). Also, I need 5 position and 4 position connectors. Even better if buying pre-fab cables with these ends were readily available...but I will need to do some crimping anyway.
Thank you for your input!
Response by poster: Thanks for your reply BeeDo. I'll be honest and say that the reason I came here was because I was overwhelmed with choices between the Mouser, DigiKey, and Allied Electronics catalogs that I currently have occupying about 100% of my desk. So I'm still nailing down exact part numbers, pin configurations, crimp tools, and pin extraction tools
I read this guide on using Molex connectors to repair pinball machines. http://www.pinrepair.com/connect/
In general these look like what are used inside of PC enclosures to run power to CD-ROM drives, etc.
The cabling I have is stranded, normal shielding, 24 AWG, and 4-conductor (+1 shield "drain"). Omega's "TX4" multiconductor cables is what I'm using.
I guess I'm more interested in receiving advice about what worked for others in their applications and that they "liked" a particular connector. I did not know that digi-key would pre-assemble cable bundles. That is useful to know and I will probably take advantage of that.
Thank you for your time and input!
posted by nickerbocker at 9:07 AM on May 30, 2013
I read this guide on using Molex connectors to repair pinball machines. http://www.pinrepair.com/connect/
In general these look like what are used inside of PC enclosures to run power to CD-ROM drives, etc.
The cabling I have is stranded, normal shielding, 24 AWG, and 4-conductor (+1 shield "drain"). Omega's "TX4" multiconductor cables is what I'm using.
I guess I'm more interested in receiving advice about what worked for others in their applications and that they "liked" a particular connector. I did not know that digi-key would pre-assemble cable bundles. That is useful to know and I will probably take advantage of that.
Thank you for your time and input!
posted by nickerbocker at 9:07 AM on May 30, 2013
I've always seen and used the connectors you hate (and understand why). If I were you I'd start by trying out cat5, just because it's so easy - you can get breakout boards from Sparkfun for about 5 bucks - for a couple of those, a breadboard, and an afternoon you can test a bunch of topologies (eg twist every signal w/ ground, twist differential pairs if you have them, etc) and find out if you're lucky enough to get to do it the super easy way.
posted by range at 9:27 AM on May 30, 2013
posted by range at 9:27 AM on May 30, 2013
Response by poster: Thanks for the input, range. I'm fairly confident that cat5 would be just fine, but I prefer this TX4 stuff because it is stranded, shielded, and the price is right. I use Cat5 all the time for TTL binary signals between devices. RJ45 connectors also don't meet my requirements of having mating ends of a cable. You have to use a coupler to connect two cables together.
Thanks for the reply.
posted by nickerbocker at 9:35 AM on May 30, 2013
Thanks for the reply.
posted by nickerbocker at 9:35 AM on May 30, 2013
I'm going to take the opposite position from BeeDo. Soldering has its places, but crimps can be totally awesome. In the shop, custom cabling typically ends up being .100 spaced connectors for use in computers, servers, and other electronics projects, they're standard, small/dense, but not a real pain to work with. I would never want to crimp the little pins for these things without the proper tooling... I would not want to solder them either... but given the $250 tool to do the crimping, and having done it that way for many years, I cannot imagine doing it any other way. The tool is completely awesome, holds the pin in position just so, you slip the wire in, pull, and fabulously perfect and strong crimp every time, insulation and wire grabbed perfectly by the terminal, looks professional. Takes surprisingly little practice. Since .100 is common spacing for breadboards, protoboards, and all sorts of stuff, I find myself .100-connector-izing things that maybe don't need to be, just because it's so easy.
The pins look like this: http://www.molex.com/pdm_docs/sd/700580088_sd.pdf and it is hopefully easy to see why some precision is called for.
I have no particular product to recommend to you as far as connector options go, but if you're working with something like 24AWG, you should at least consider whether or not a crimped solution might give you better options to pick from.
posted by jgreco at 9:39 AM on May 30, 2013 [2 favorites]
The pins look like this: http://www.molex.com/pdm_docs/sd/700580088_sd.pdf and it is hopefully easy to see why some precision is called for.
I have no particular product to recommend to you as far as connector options go, but if you're working with something like 24AWG, you should at least consider whether or not a crimped solution might give you better options to pick from.
posted by jgreco at 9:39 AM on May 30, 2013 [2 favorites]
I could probably still wire a Bulgin Buccaneer connector in the dark, even though it's been years since working with them. They quite large, but light, waterproof, use screw terminals (though certain sizes are available with crimp or solder), and all the bodies/cores/panel mounts are interchangeable. The sealing cap also doubles as the wrench for removing the core.
Failing that, both Neutrik and LEMO are really fantastic, but may have expensive proprietary crimping tools.
posted by scruss at 9:44 AM on May 30, 2013
Failing that, both Neutrik and LEMO are really fantastic, but may have expensive proprietary crimping tools.
posted by scruss at 9:44 AM on May 30, 2013
Response by poster: Thanks for the input!
jgreco - What crimp tool do you use? I'm thinking that I will be going the Molex route. They gel with what I'm looking for I think.
posted by nickerbocker at 9:55 AM on May 30, 2013
jgreco - What crimp tool do you use? I'm thinking that I will be going the Molex route. They gel with what I'm looking for I think.
posted by nickerbocker at 9:55 AM on May 30, 2013
It didn't sound like what you needed to me, I was mainly encouraging you to at least consider crimping. With a little practice learning to use the tool, it is very unusual to have bad connections, which was really the point.
The Molex product we use here resembles, but isn't the same as, the type of .100 connector body found in generic PC's. The body is a little longer and retains pins differently. They're part of the Molex C-Grid® SL™ 70066 system. A typical two-pin housing is the 50-57-9002; look for Digi-Key WM2800-ND. Note that this is the male AND female housing. You use a male pin like 16-02-0115-C (DK WM2515-ND) to make a male cable connector. You get to pick the pins as male or female, tin or gold, and small or large AWG. Pins should be crimped with 11-01-0208 (WM9917-ND, but DON'T pay DigiKey $250 for it, look on eBay, think I saw one for $125). Housings come as plain, latching, ramped, single-row, double-row, etc.
Other options, such as connectors of the type used for case fans, ATX power supplies, and hard drives are also fairly readily available and in some cases may have less-expensive tools available to do the crimping. I can look up some part numbers later if any of that sounds useful.
posted by jgreco at 10:23 AM on May 30, 2013
The Molex product we use here resembles, but isn't the same as, the type of .100 connector body found in generic PC's. The body is a little longer and retains pins differently. They're part of the Molex C-Grid® SL™ 70066 system. A typical two-pin housing is the 50-57-9002; look for Digi-Key WM2800-ND. Note that this is the male AND female housing. You use a male pin like 16-02-0115-C (DK WM2515-ND) to make a male cable connector. You get to pick the pins as male or female, tin or gold, and small or large AWG. Pins should be crimped with 11-01-0208 (WM9917-ND, but DON'T pay DigiKey $250 for it, look on eBay, think I saw one for $125). Housings come as plain, latching, ramped, single-row, double-row, etc.
Other options, such as connectors of the type used for case fans, ATX power supplies, and hard drives are also fairly readily available and in some cases may have less-expensive tools available to do the crimping. I can look up some part numbers later if any of that sounds useful.
posted by jgreco at 10:23 AM on May 30, 2013
Oh also meant to say, memail me if you decide to go this route. The tooling is expensive and we can mitigate your risk if you wish to send a foot of cable here, I can toss some connectors on and send it back to you to eval.
posted by jgreco at 10:39 AM on May 30, 2013
posted by jgreco at 10:39 AM on May 30, 2013
Response by poster: Thanks jgreco. That gives me some things to look at. I don't have any problems with crimped connectors and I'm highly interested in getting the correct tools for crimp connection in-spite-of the cost.
You mention that the same connector body is used for male or female pins, but if I have one WM2800-ND with female pins and another WM2800-ND with male pins, would they mate with each other? Or is there another connector body to be used? I'll dig through the "catalog" of that line of Molex connectors.
posted by nickerbocker at 10:40 AM on May 30, 2013
You mention that the same connector body is used for male or female pins, but if I have one WM2800-ND with female pins and another WM2800-ND with male pins, would they mate with each other? Or is there another connector body to be used? I'll dig through the "catalog" of that line of Molex connectors.
posted by nickerbocker at 10:40 AM on May 30, 2013
Response by poster: Oh I see. The male would protrude out of the housing and mate with a female pins that are in the same type of housing. Hmm, I like these and can probably use them for some wire to circuit board applications. This is more of a wire-to-wire application, but something like that with a "latch" that locks the connectors together would probably work for my application.
posted by nickerbocker at 10:49 AM on May 30, 2013
posted by nickerbocker at 10:49 AM on May 30, 2013
Yeah, I haven't actually looked in great detail but they do have latching options. See WM2900-ND which mates with WM6675-ND for a two-pin variant. The housing is just bigger to accommodate the extra latch stuff.
posted by jgreco at 1:12 PM on May 30, 2013
posted by jgreco at 1:12 PM on May 30, 2013
This thread is closed to new comments.
When I used to do stuff like that, I never trusted crimping, always soldered connections. The cigarette lighter torch type soldering gun is your friend in the field.
In general, check out Digikey for a gajillion types of connectors. You can even order custom cables from them with the connectors already attached, if you have more money than time.
posted by BeeDo at 8:55 AM on May 30, 2013