Gentleman hi to everyone.

I am new here and someone of you might be able to help me with the issue that i have.

We have station for Car Camera Testing, testing is done thru a video receiver connected to a software - where camera during testing reads QR code and shows eitheer PASS or FAIL.

On the attached diagram you can see the complete circuit of the testing protocol.

Now the problem is, XC connector is wired at our facility. And often the workers missplace the wires places between pins 5 and 12 on the XC.

Both of the wires are ground, and even with missplaced wires the test passes - but on later stage when the camera got installed on the car shows problem.

I need to invent some solution that will prevent the camera to go ON if those two wires are missplaced on the connector - or to fail the test.



I need to sort this out, as i am in Maintenance there and my job depends on it.
AND TO BE HONEST HAVE NO IDEA WHAT TO DO.


THANK YOU IN ADVANCE,
KRIS

 

Welcome to AAC.

My first inclination is to suggest a pair of connectors as a "shim" between the camera and test fixture. You could then put a signal on that pin, say 440Hz at 1V and detect that to it is present on the right pin of the test fixture. If not, fail.

 

Yaakov, thank you for your kind replay.
I am more electrical guy than electronics, so want to ask, your proposal above do that will not be the same scenario as for example if i put the signal let say on pin 12, and again the wires are missplaced between 12 and 5 it will be the same as both wires have same role GND ?

Tnx

 

Yaakov, thank you for your kind replay.
I am more electrical guy than electronics, so want to ask, your proposal above do that will not be the same scenario as for example if i put the signal let say on pin 12, and again the wires are missplaced between 12 and 5 it will be the same as both wires have same role GND ?

Tnx

As far as your DC ground is concerned, yes, the wires would be common. But an AC signal can be isolated to the one pin using a filter (which will allow the DC to pass but will block the AC). This means on the commoned side of the two pins, in the camera, there would be no AC signal present, something like:

​

Where starting from the bottom, we have an adapter with two mating connectors. Between them is a filter (simplified as a choke but it would be a bit more complicated), and above the filter a 1KHz, 1V signal is injected. It can’t get past the filter into the camera, but it does go “up” through the other parts.

The test adapter is plugged in to the camera, and the cable under test is plugged into the test adapter on one end, and the test fixture on the other. The connection coming from the test fixture connector is connected to a detector for the 1KHz signal, followed by a filter like the one below.

The filters allow the DC to pass, so the rest works normally. The 1KHz detector gives a go/no-go indication that the correct pin in the cable under test is connected to that line. If it was swapped, the 1KHz signal would appear on the other wire (which could be detected to indicate a swapped wire, if you want, but it doesn’t seem necessary).

The signal from the detector can be used however you want to indicate a mis-wired cable.

 

So your proposal is above filter to be applied to the pins 12 and 5 on my diagram - am i right ?

Also what is your proposal, which type of filter shall i use considering the circuit works on 5v DC?

 

When I was responsible for electrical testing on the GM "U" vans, each connection point had a dedicated connector that only fit one way. That prevented problems.
But it appears that the camera has four separate but identical connectors that are different colors. That is an incorrect design, because the correct connection matters.
Is there any electrical difference between the connections that the tester machine could detect?? If the resistance is slightly different that could make a check work.

 

Bill thank you for your comment.

I tried Yaakov solution today but didnt work.
As for the resistance it is same both sides.

You know its stupid that the camera is getting negative on pin 5 and same passes thru the camera and shows on pin 12 as negative for powering the dongle for the video testing.

No matter what you do, as it is closed loop of negative dc there is no chance wires to be recognized if missplaced.

On the testing do not matter if they are missplaced, as long the dongle gets negative the test is PASS. Change both wires again the same.

But from some reason once the camera is installed on the car, do not work - i assume there is different circuit where negative dc input only goes on pin 5 and continues thru pin 12 no one know where.


I am desparate with this s...., and to be honest starts annoying me.

 

If there is something in between those two connections then it should be something that you can measure. Does your electrical tester have a way to measure the voltage on inputs? Can you measure the resistance between those two connections with a digital meter in both directions? There might be a diode or a resistor in that circuit.

The testers that I used were able to read the voltage on each connection. For three years I was doing the electrical tests on GM vehicles. Two model years with the "U" vans and then one more year with the pickup trucks. And in between, with the engine electrical harness on another vehicle. So I do have automotive electrical testing experience.
Just what does the present test do?? Perhaps the two wires that get exchanged are not connected when the camera is powered.
That does seem like a design flaw that the vendor should address. Why are there two identical connectors on wires that must not be exchanged?? THAT IS a design error!
Worst case you could add a visual inspection to the test sequence. The union operator complained bitterly about the extra 5 seconds it took..