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4 to 20 mA Calculator

Industry Standard Signal Conversion — Global Process Control

Critical Instrumentation: This 4 to 20 ma calculator ensures accurate sensor scaling and loop diagnostics.

Convert process variable to 4-20 mA using our 4 to 20 ma calculator.

e.g., 0°C, 0 bar

Enter values

Calculate loop voltage and resistance using our 4 to 20 ma calculator.

3.8–20.5 mA

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Diagnose 4-20 mA loop faults using our 4 to 20 ma calculator.

Enter values

HART digital signal and advanced scaling using our 4 to 20 ma calculator.

Configure scaling

4 to 20 mA Calculator: The Global Standard for Process Control

Used by instrumentation engineers worldwide, our 4 to 20 ma calculator ensures reliable signal transmission in oil & gas, pharmaceuticals, and manufacturing.

"Signum fidele" — Faithful signal.

How the 4 to 20 mA Calculator Works

Core equations:

mA = 4 + 16 × ((PV - LRV) / (URV - LRV))
V_drop = I × R_loop
% = (mA - 4) / 16 × 100

4 to 20 mA Calculator: Four Essential Modes

Basic Scaling Mode

Direct PV to mA conversion in our 4 to 20 ma calculator.

Voltage Drop Mode

Loop power and resistance analysis.

Loop Diagnostics Mode

Fault detection and troubleshooting.

HART & Scaling Mode

Digital HART configuration and square root extraction.

4 to 20 mA Calculator: Standard Signal Levels

Current % Status
0–1 mA — Open Circuit
3.8 mA 0% Live Zero
20.5 mA 103.125% Overrange

4 to 20 mA Calculator: Loop Power Guide

  • 24VDC standard — 12–36V range
  • 250Ω resistor = 1–5V for PLC
  • 500Ω max at 20 mA with 24V
  • HART: 1200 Hz digital overlay
  • IS barriers: Reduce available voltage

Pro Tips for the 4 to 20 mA Calculator

  1. Use shielded twisted pair cable
  2. Ground at one point only
  3. Check for ground loops with multimeter
  4. Calibrate at 4, 12, 20 mA
  5. HART: Minimum 230Ω loop resistance

Precision in Every Signal

From field to control room, our 4 to 20 ma calculator ensures zero downtime.

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