Free Tool

Scale 4-20 mA Signals Correctly

Convert raw counts to engineering units (and back) with transparent formulas. Includes NAMUR NE43 fault detection helpers. Runs entirely in your browser.

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PLC Analog Scaling Calculator interface showing scaling parameters

Why This Scaling Calculator Helps

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Raw ↔ Engineering Units

Convert counts to °C, bar, %, etc. and verify the math quickly.

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4-20mA & 0-10V

Work with the most common analog input ranges used in PLC panels.

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NAMUR NE43 Helpers

Plan fault thresholds and clamping behavior for broken-loop detection.

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Transparent Formulas

See exactly how slope and offset are computed; no black boxes.

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PLC-Friendly Output

Get parameters you can paste into Siemens / AB / Beckhoff scaling logic.

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Runs Locally

Everything runs in your browser—no upload, no account, works offline.

Scaling Features

Compute Slope and Offset in Seconds

Enter your input range and engineering range once and get the exact slope/offset needed for linear conversion. Great for commissioning and quick sanity checks.

  • Counts → EU and EU → counts
  • Avoid off-by-one and sign mistakes
  • Metric and imperial-friendly
Analog scaling slope and offset results

Plan Fault Detection (NAMUR NE43)

Set practical alarm and fault thresholds for 4-20mA loops and keep your PLC logic consistent across projects.

  • Low/high fault thresholds
  • Clamp or pass-through strategies
  • Commissioning-friendly outputs
NAMUR NE43 threshold calculations

Generate Parameters You Can Implement

Use the computed values directly in your PLC blocks and keep your scaling consistent across platforms and projects.

  • Works with typical AI modules
  • Engineering-unit min/max outputs
  • Quick verification during startup
PLC parameter outputs for analog scaling

Common Questions

Most issues come from mismatched raw ranges (e.g., using 0–27648 vs 0–32767) or applying slope/offset in the wrong order. Double-check your module counts and whether your logic clamps before scaling.
Many sites follow NAMUR NE43 guidance. You typically alarm below ~3.8mA and fault below ~3.6mA (exact values depend on your standard). Configure thresholds and decide whether you clamp to 0% or propagate a fault state.
Yes. The math is platform-agnostic. Use the computed slope/offset (or equivalent parameters) in your preferred function block or ladder logic.
No. Everything runs in your browser. Inputs are not uploaded and the tool works offline once loaded.

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