Test circuit for wire harness
Test circuit for wire harness
(OP)
I have an R&D project, where the objective is to test multiple conductors on a wire harness with a voltage source. One particular harness has 16 conductors all pin to pin. There are thousands of these harnesses, and I am looking at building a test fixture to test them in the quickest way possible. I have thought about using a PLC, but I am really getting stumped, thinking there must be an easy way. Any Ideas?





RE: Test circuit for wire harness
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Test circuit for wire harness
RE: Test circuit for wire harness
RE: Test circuit for wire harness
Without narrowing down the problem for us, we will spend at least 8 hours trying to figure out the requirements so we can help you develop an adequate solution.
RE: Test circuit for wire harness
The testing procedures will get more compliccated as you move down the list. 16 outputs from a PLC fed to the pins of one connector and 16 inputs fed from the pins of the other connector will let you check for continuity, cross connections, and line to line shorts. Send a signal to each pin and check that it returns on the proper input line. Then or the signals returning from the other 15 pins. Any output from the or will indicate a cross connecion or line to line short. Repeat 15 times for the other 15 lines.
respectfully
RE: Test circuit for wire harness
PS: Does anyone know why threads occasionally just disappear - usually after I've posted a particularly good response?
RE: Test circuit for wire harness
I have noticed that threads that may be students or homeowners tend to disappear. If someone red flags a thread as a student or homeowner post, and the moderators agree, it's gone.
respectfully
RE: Test circuit for wire harness
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Test circuit for wire harness
The requirements are just to verify that the wiring is correct. Testing for shorts or opens. I am trying to test various wire harnesses. One in particular is 16 Pins. Each one goes from pin to pin. 1-1 2-2 and so on until 16 to 16. We manufacture 100 per week, and have been having quality issues with incorrect wiring. So I am trying to assemble a test fixture, size is no restriction. Ideal it would be a test fixture that would be put on a technicians bench. Every unit must be tested, one at a time. I will be making it myself. There will be user interaction, with the testing technician plugging each harness in a test fixture, my plan from there would be he hits a test button, and gets either a
pass or fail indication. Temperature is not an issue. I will need about 15 different test fixtures that test a variety of harness, so each one will be different. But for now I am just trying to get through one. And thanks to everyone for all the help.
RE: Test circuit for wire harness
The first thought is just put two connectors on the board for each end of the cable and source enough power on one end to light LEDS on the other. Just plug in and if all the lights on the other end light up you have continuity! Problem is if a couple are crossed you may still get all the lights on. DOH! So you do the exact same thing - you just use a PC or something to scan the power down the connector endlessly. The person testing the cable jacks it in then watches one or two full cycles to see if the lights all light sequentially. If they do you know there are no crossed connections. No buttons too push! Run the scan fast so there is no sitting around watching each light switch. A human will instantly detect a blink pattern anomaly.
Set things up for the largest number of lines you would expect. I would consider a family of circuit boards that connect to your logic machine (PC or ?) with one large standard connector and then each having a family of of connectors for the cables you want tested. Sit down and plan a board to test all the cables you currently want tested then make new boards as future cables appear.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Test circuit for wire harness
RE: Test circuit for wire harness
You may want to use enough current to "smoke' any bad connections. This may be two tests, one in parallel at high current to test the integrity of the connections followed by the resistor test to check connections.
respectfully
RE: Test circuit for wire harness
These guys make rotary switches with up to 12 positions. The multiconductor cables we had to test had Cannon plugss on both ends.
http://
I have seen similar test setups using a telephone stepper relay. Trouble with that is the only stepper relays left in the world may be in museums.
RE: Test circuit for wire harness
RE: Test circuit for wire harness
htt
We use one at work. It has a PCB with patterns to install connectors to test things such as ribbon cables and DB connectors but it could be used for any type of cable by adapting the right plugs to it.
RE: Test circuit for wire harness
a panel with an array of 10 by 18 would be small and test ten cables at a time or if you found a quick way (looped connector with jumpers)to connect two wires together you could test 20 at a time and so on.
this would work for continuity testing and they are available in a variety of voltages---mostly used for aircraft avionics fault indication
They could also be arranged to detect shorts IE two bit balls latch when voltage is applied to one wire.
you could do this with a series of buttons or switches but that would take a long time so maybe a program to apply the voltage would be better
just some food for though---hope it helps
RE: Test circuit for wire harness
RE: Test circuit for wire harness
I can tell you that cables are one of my biggest headaches when commissioning equipment. As we 'certify' our product, a failure in any cable requires a recertification. It drives me nuts thinking that any manufacturer will send out a cable that hasn't been internally 'certified' to some minimum value (exceeding customers requirements).
RE: Test circuit for wire harness
Honestly, if you want a turnkey supplier for a cable tester, you are out of luck. Your connectors are your connectors, but modifying a simple cable tester with an adapater YOU can make is a fast way.
http:
Note.... like all technical questions, the right answer depends on the quality of the question. Your query is limited to the word 'test', which can range from measuring the length to full dynamic testing of each conductor. The difference in cost for the two is enormous.
For simple cable wiring verification, use something like the one I provided a link to and modify it for your purposes. $140. (I have one in my lab.)
RE: Test circuit for wire harness