continuity test

[barcode]

I came across a machine the other day with a check station, this station is checking for continuity on a previously installed wiring harness. and I was wondering if there is another way of doing it. they seem to be just feeding +24vdc to one pin and waiting for it to come back to the PLC card on the other pin, this works but the operators have figured out how to short the pin to the frame of the machine which results in blowing the fuse or shorting the card.

if I were to isolate a separate voltage supply say five volts and not ground it to the common ground then it should not short basically i think.

 

[ericgibbs]

I came across a machine the other day with a check station, this station is checking for continuity on a previously installed wiring harness. and I was wondering if there is another way of doing it. they seem to be just feeding +24vdc to one pin and waiting for it to come back to the PLC card on the other pin, this works but the operators have figured out how to short the pin to the frame of the machine which results in blowing the fuse or shorting the card.

if I were to isolate a separate voltage supply say five volts and not ground it to the common ground then it should not short basically i think.

hi,
As the 'output end' of the wire in the cable harness is connected to the input of a PLC, isnt it possible to fit a current limiting resistor in the +24Vdc feeding the 'input end' of the wire?
After all, you are only testing for continuity not a resistance value.

Eric

 

[Pommie]

but the operators have figured out how to short the pin to the frame of the machine which results in blowing the fuse or shorting the card.

I think you are going about this the wrong way, the above should be a sackable offense.

Mike.