Need a schematic for testing "miswire circuits"

[mooimooi]

Hi,
Is there anyone out there to help me with providing
a test circuit for testing "miswired circuit" for a
harness?. The harness may range from 2 way to 20 way.

Thanks
Chandra

 

[MMAshwin]

Hi,

I designed , built but never completed the paper work for a PIC controlled, LCD output cable tester/identifier.
Now after reading your question I thought about resurrecting it, but instead (due to my work load) found you a you may find useful.

http://www.electronic-projects.net/projects/cable_test/index.shtml

Any help ?, yes no let me know.

Regards

 

[nbucska]

I think the most cost-effective and simple way would be
to use a cheap, old PC with parallel interface to the
demultiplexer-multiplexer circuit.

I suggest, decide the maximum # of wires and pins and
for each harness make an adapter.

<nbucska@pcperipherals.com>

 

[mooimooi]

Hi
Thank you very much for speedy reply. I am reading the
description now and will definitely get back to you on
the progress on this project.
Joy to You my friend,
Chandra

 

[mooimooi]

Hi Messrs Laffalot,

I have read the description, and found this to be
very nice for electricians troubleshooting electrical
faults involving Open or short circuits or miswiring on
long distance cables. I am wondering if is possible to modify the circuit so that the tester can be used to check
the harness on the spot. You see, the lenght of harness is
about 400mm only! Basically I would be able to set the
number of circuits using a dipswitch and then once I connect
the harness into the connectors ( say 10 ), the tester must
be able to tell me that circuit 1 of Housing A is connected
to circuit circuit 1 of Housing B. If there is an open due
to the crimping then it should show open and if there is
miswire ie circuit 1 or Housing A is conneced ot circuit 2
of housing B, then LED must show that this is Wrong Orientation or miswired. Test time should be less than 1 sec.

 

[MMAshwin]

Hi,

If that solution works over a long distance then it will work of 400mm.

Usually you find its not true in the opposite. i.e if its designed to work over short distances then it cann't drive the signal to test longer ones.

Failing that if you can program a PIC. Then use a 16F877. It has more than enough I/Os to test a 10 way cable and tell you if they're Open CCt or miswired.

Any help ?, yes no let me know.

Regards

 

[mooimooi]

Hi Laffalot,
Thanks alot for your advise, I intend to build the above
ETI tester and will let U know once its kicking.

Also I am interested to learn how to program the 16F877 PIC.
Could you let me know of any useful websites that may show
how this is done.

Thanks alot again for your help.

Best Regards
Chandra.

 

[MMAshwin]

Hi,

Although I recomended the 16F877 it is just one in a whole line of microcontrollers.
For the most part they all use the same instructions witha few exceptions. What they do differ in though is their features.

As an example the 16F84 has 13 I/O lines and 1K of memory where as the 16F877 has 32 I/O lines and loads of memory, a handfull of A/D converters higher clock speed etc.

My point being if you can program a 16F84 its a small step to program the 16F877, you just have to learn the extra features, the core of your code being the same.

There are also a number of easier computer languages you can program the IC with like BASIC and C. These higher level languages make programming them easier.

Remember some of these links are for the 16F84. The 16F877 is just a beefed up action packed big brother !

Anyway onto the links:

http://www.piclist.com/techref/piclist/begin.htm

http://www.piclist.com/techref/piclist/cheapic/index.htm

http://pc-tek.hypermart.net/pic.html

http://www.users.globalnet.co.uk/~jchap/tvpropi2.htm

http://www.rentron.com/Myke3.htm

For a demo in Pic Basic see:

http://www.crownhill.co.uk/item410.htm

Any help ?, yes no let me know.

Regards

 

[mooimooi]

Hi,

Thanks for your valuble inputs, I will just try
doing this.

Best Regards
Chandra