Connector Life Cycles

conn-collection-300b
Cirris buys connectors "off-the-shelf". 

dualrow-new-300 
New, dual row connector with 
crisp, clean unblemished pins. 

worn-out-300 
A very well worn SCSI style d-sub connector 

 
 

How Long Will My Adapter Last?

We regularly receive calls asking about the life expectancy of Cirris test adapters. This is a very difficult question to answer because there are so many variables to consider. Here we'll attempt to shed some light on those variables, provide you with useful information, and offer some ideas and suggestions to help you get maximum life out of your mating test adapters. 

Cirris doesn't "make" connectors, we buy them like everyone else!

A regular misconception is that, because Cirris sells adapter cards we make connectors. We don't, we buy them from connector manufacturers like everyone else. We want our adapters to last as long as possible so we always look for the highest quality, longest life connectors that we can find. We do extensive life-cycle testing to assure that you get as many cycles as possible out of your Cirris adapters. 

 

Manufacturers Specs:

Connector manufacturer's data sheets generally include technical specs on electrical properties such as current and voltage ratings, contact resistance and mating cycles. The "mating cycle" spec tells you how many mating cycles you can expect for the connector to maintain its rated "contact resistance" value. This will vary depending on the type of metal used (tin, copper, brass, gold, etc), the type of plating (usually gold) the thickness of the plating, and other factors. Most manufacturers will offer several grades of connectors with differing mating cycle ratings. Cheaper connectors (tin plating) may be rated for as few as 10 to 50 cycles, while the more expensive connectors (thicker gold plating) are generally rated for 500 cycles. 

 

500 mating cycles! Why that's barely a day's worth of testing!

It's true, that seems like a very small number of mating cycles for a test adapter , but remember, the manufacturer's spec is for how many mating cycles you can expect at the specified contact resistance rating. 
(In most cases, customers get many times more mating cycles out of our adapters.) Below are several considerations that go into determining how many cycles you might get. 

 

Connection Resistance Test Threshold:

Electrical connectors, like the tires on your car, wear out with use. Obviously, the lower your pass/fail threshold for connection resistance, the fewer number of mating cycles you'll get before you start to see high resistance failures. For example: a 25 pin D-Sub adapter rated for 500 cycles at less than 25m ohms might give you 1000 tests with a .1 ohms threshold. If you increase the test threshold to .5 ohms you might get several thousand tests. At 1 ohms that could increase to 5000. Go up to 5 ohms and you may get 10,000. (these numbers aren't a guarantee, only to give an example) 
flex-point-300 

Female tension points can be over stressed
when bent pins are inserted. 

pin-deflect-300
 
Larger deflection area spreads out tension 
stresses and improves tension life cycle. 

 

Different connectors wear out different ways:

Depending on the mating style of the contacts (pin/socket, blade/blade, leaf spring, etc.) The actual "mating point" of a contact to contact mate in electrical connectors is usually a "high spot." As one high spot wears down resistance might increase until it becomes so worn that a new high spot begins to make contact. In these cases it has been shown that resistance may gradually increase, then drop back down, then start increasing again as the new high spot is worn off.

Male vs. Female Contacts:

With male pins it's all about the plating, whereas with female contacts it's not just the plating but the "springiness" of the metal to maintain contact mating pressure. Good contact pressure helps with low contact resistance, even when the plating wears away. Range of motion in female contacts is a key factor to their effective life expectancy. The "bend radius" of the spring contact is key; a sharper bend fatigues faster and will lose its mating pressure quicker than a more gradual radius.

The metal used in contacts can have a big effect:

Connector contacts are made of metal. The higher the quality the better. Cheaper connectors will use "copper alloy" (the alloy is generally unspecified). Higher quality connectors will use "phosphor bronze" or "beryllium copper." These connectors cost substantially more, quite often have longer lead times and often go obsolete because low price wins out over higher quality in the marketplace. For example, years ago T&B Ansley manufactured high-quality IDC connectors using beryllium copper contacts. They were expensive but extremely durable. They quit making them because they didn't sell well enough to justify the higher cost. 



 dualrow-used-300
Photo above shows results of "peeling" 
connector out of mating connector. 

 dualrow-used-300b
This photo illustrates casual pin 
straightening. Potential damage to 
tested connectors is likely. 

 

 

"Wiping action" helps, even after gold plating is worn off:

Even after the precious metal plating is worn off of a test adapter, exposing the base metal, there is a certain amount of wiping action each time a new cable is plugged in that helps prolong the effective use of the adapter. However, if a "worn" adapter sits for a long time between uses it is possible that oxidation build up will give high resistance readings once the adapter is first put back into service. 

Gorillas vs. Surgeons:

One of the most obvious, but often overlooked, aspects of adapter life is how they are handled. Cables "jammed" or forced into adapters can result in bent and broken pins significantly reducing the life cycle of the adapters. Adapter stuffed into drawers or filing cabinets can also lead to bent pins. Cirris' "Adapter Trays" can help you keep adapters from being damaged. When unplugging longer connectors, if operators "peel" them out of the test adapter instead of unplugging straight up you will see pins on the ends of the connector become bent, again greatly reducing the life cycle of the adapter. 

Straightening out bent pins:

It is not uncommon for male pins to get bent while testing. If you straighten them, care must be taken. Pins straightened with needle nose pliers can be left with jagged metal which can damage female contacts that are subsequently plugged in. Likewise, pins that are "straightened", but not perfectly so, can "stretch" open the female contacts damaging their contact pressure. 



 receptical-c

Unique dual-metal PV receptacle contact maintains
contact pressure through 1000 mating cycles. A
beryllium copper spring provides high normal force
at the mating interface, while the brass contact body
produces a reliable, gas-tight crimp termination.

install-coverplates-300
 
Always install cover plates!

 

How many times can you plug adapters into your Cirris tester?

The female sockets used on Cirris testers were specifically chosen with high mating-cycles in mind. We use a "PV" receptacle contact, which is designed specifically to keep its mating pressure and plating for 1000 + mating cycles. Again, due to the wiping action while plugging in adapters, you're likely to get many times that number, provided you take care to not insert adapters with bent pins or "jam" adapters in at an angle, which can damage the receptacle's contacts and negatively impact the mating pressure. 

 

pvc-conn-smpv-assembly 

 

ALWAYS Use Cover Plates!

It is extremely important to always use the cover plates that are provided with Cirris testers. The cover plates "lock in" the test adapters and prevent undue wear on the PV receptacles that the adapter cards are plugged into. Failure to regularly use cover plates can significantly reduce the life of your PV receptacles. 



lg-whole337 
Replaceable connector adapter concept. 

 savers 300
photo of connector extender. 


ecc-adapter 
Sample of ECC pogo pin fixtures.

 

 

Suggestions for increasing the life of test adapters:

 

Replaceable Connectors:

Many Cirris adapters are offered with "replaceable connectors" These allow you to unplug and replace the mating connector without having to replace the entire adapter card. While this approach allows you to cost effectively extend the life of your adapter cards it does add a small amount of extra resistance since the connectors are plugged into sockets soldered onto the card.


*(Note: customer's often ask if we can replace worn out connectors on their adapter cards? While you CAN unsolder and re-solder new connectors on adapter cards, it is labor intensive. It would likely cost as much in labor to do this as to buy a new adapter. You can replace them yourself, but usually only once or twice before you lift pads on the pc board.) (Also, when replacing connectors yourselves YOU MUST take care to properly clean them after soldering if they are used for high voltage testing, or you will have Hipot failures) 

 

Connector Savers:

For some styles of connectors you can plug a "sacrificial connector" or "connector extender" onto the connector on the adapter board. When this connector wears out you remove and replace it. As with the Replaceable Connectors this approach adds a small amount of resistance to your testing. 

 

Spring Loaded Pogo Pins:

One of our partners, ECC, manufacturer's spring loaded pogo pin test fixtures. They can adapt their fixtures to standard Cirris adapter cards, offering another longer-life option. As with Replaceable Connectors and Connector Savers pogo pin fixtures add some additional resistance to the equation. When using pogo pin fixtures do not expect to set connection resistance thresholds much lower than .5 ohms. 

 



shorting-cable-300 
Example of shorting plug use to test adapters 

 25pos-dsub-test-300
15 Pos. D-Sub shorting plug. 

 

 

Bad Cable or Worn Out Adapters? How can I Tell?

One of the real challenges is; how can you tell when your adapter is worn out? Once a connector is worn to the point of failing you will start to get high resistance failures in your testing. But how do you know if it's a worn out adapter, or a true failure in the cable under test? 

Regularly "test" your adapters with shorting plugs:

You can build adapter "test plugs" to help you quickly and easily determine if a high-resistance failure is in your cable-under-test or in you test adapter. Click here for a link to detailed instructions on how to do this. 

In Summary

  1. Connectors are rated for far fewer Mating Cycles than we wish.
  2. Many factors go into determining how many mating cycles you will actually get
    • Connection Resistance threshold
    • Wiping action
    • Plating
    • Spring retention
    • Proper handling
  3. There are several possibilities of how you might increase the life of your adapters
  4. You should regularly test your adapters to determine when they are worn out