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Old December 2nd, 2019, 09:12 AM   #1
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Join Date: Feb 2014
Location: West Michigan
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4-20ma Passive Device Wiring between 2 boxes, with Seperate Power Supplies

Ok, so I have 2 boxes with separate power supplies they are going to be about 300 to 400ft apart. the Main Box as the PLC in it with the Analog Inputs, The remote box has the 4-20mA devices/drivers in it. The 4-20mA device/drivers are passive so I am supplying them with the Power Supply in the Remote Box. My question is, does it matter how I handle the 0V Bond / Return?

Option 1: a Single-wire to bond 0V together for both boxes.

Option 2: a Return wire for 0V for each signal, and another wire to Bond 0V.

See attached schematics (Note: this was made as an example only. So don't nitpick it, this is not the real schematic)

Side Note: I will get all the current flowing back to the Remote Box correct? So in other words, if I have 4 signals running at 10mA I will get 40mA returned to the Remote Box. Whether it is on 1 wire or spread across multiple wires. Correct?

Last edited by theColonel26; December 2nd, 2019 at 09:18 AM.
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