Answer / carl_ellis

An i/e converter is a current to voltage converter. A
current to voltage converter is a resistor. Electrical
current through a resistance develops a voltage. Ohms Law
determines the voltage drop, E = I/R.

An i/e resistor is typically used in the process world in
4-20mA current loops as the component installed across the
(+) and (-) terminals of an analog input because analog
inputs expect a voltage input. The majority of DCS, PLC,
recorder, controller and indicators use 250 ohms as an input
but other values are used, 1 ohm, 10 ohms, 62.5 ohms, 50
ohms, 100 ohms. Do not assume an analog input is 250 ohms.

Carl Ellis
Measure First

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