4-20mA Current Loop Calculator
4-20
4-20mA Current Loop Calculator
Convert between loop current, percentage, and engineering units, plus a loop-power headroom check
Conversion
Loop Power Check (optional)
Result
Engineering Value
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Percentage of Range
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Formulas: % = (ImA − 4) ÷ 16 × 100. Engineering value = min + %×(max − min). Loop power check: at max
current (20mA), voltage dropped across the loop resistance is Vdrop = 0.020×Rloop; the transmitter needs
Vsupply − Vdrop ≥ Vcompliance to have enough headroom to regulate the current correctly across the
whole 4-20mA range.
