Fuse 2-wire analog signal

boneless

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Hi all!

Silly question, I think..

Sitting here, drawing up a project, that receives 4pc 4..20 mA signals from another location.

They say that the signals have galvanic isolators installed. But still we have had two instances where (seemingly) the Ai module was fried.

I am going to tie my spare channels to 0 VDC, put in my own isolators, but I am also wanting to put a couple of fuses in the system, but that got me thinking. Do I only fuse the positive side, or both sides of the signal?

The loop is powered from the other end.
 
put on positive side but both side will work,

but if you using 0 VDC beware due engineering guys love to link or share this work,

easy job,

conventional flow or electron flow
 
You don't need to fuse both wires from the other equipment as it is sending you the 4-20signal. And then 0VDC. This completes the circuit. No need for a +24VDC
 
They say that the signals have galvanic isolators installed. But still we have had two instances where (seemingly) the Ai module was fried.

Are you confident that these weren't due to a lightening strike or short circuit that affected the lengthy, interconnecting wiring? If the inputs were damaged by a high voltage spike, then fusing is not likely to provide much relief, although the signal isolators probably will.
 
I doubt it, but who knows.

I don't think it would hurt to add the fuses :).
 

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