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Old October 30th, 2002, 08:12 AM   #7
Steve Etter
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Join Date: Apr 2002
Location: Morristown, TN
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Timothy,

In your original post, you wrote:

>>I have a sourcing input tied to a momentary pushbutton.

Wire-A goes from the input to one side of the PB

Wire-B goes from the other side of the PB to 0 VDC<<

As you describe your convention and several of the other posts that agree that the grounded conductor should always be the same color, I don't really see a delima: Wire A should be blue and and wire B should be white/blue.

Neither the fact that "the switch is transmitting 0VDC to the input" nor the observation that "this is a DC [PLC] input circuit" are relevent. The switched side of the circuit (wire A) MAY OR MAY NOT be at 0 VDC at any given time, therefore it acts the same as any other PLC input wire; at any random point in time you don't know for sure at what potential it will actually be. Wire B, on the other hand will ALWAYS be at 0 VDC and its color should indicate this.

Steve
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