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digital vs analog signal cables

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helpyou

Automotive
Sep 26, 2011
79
QA
HI

Are instrument cables for analog signals (e.g. 4-20mA transmitters, 24 V power) and digital signals (e.g. 24Vdc/120Vdc Solenoid valve) the same, of same specification ? and can we use them interchangeably, if for example one digital signal cable fails and we replace with analog signal cable ?

Your comments please

Thank you
 
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Instrument cables are frequently shielded and/or twisted pair. Power cables (for solenoid valves) are not.
 
And, you never want to run 'digital' signals in the same conduit with or next to analog signals which you would likely be doing when retasking an analog wire to a digital task.

Keith Cress
kcress -
 
Although, that would be a pretty rigorous test of the common-mode noise immunity of the analog current loops, particularly with 24/120 VDC signals bouncing around.

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If you knew the process intimately and had control of the controller you might be able to pull it off. For instance if the analog is heavily filtered or you could actually stop analog reading during digital shifts it might work. Not worth the bother though.

Keith Cress
kcress -
 
The big difference between Analog and Digital is how the signal is transmitted from the source to the TV in your home. Analog TV's transmit audio and video signals over the airwaves in a manner similar to a radio signal. A Digital TV signal, on the other hand, transmits in “packets” of compressed data.

 
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