AI‑Verified Audit – PT100 RTD Calculator

Objective

This audit assesses the PT100 RTD Calculator at calibration.info. Using AI‑assisted review, the tool’s temperature‑to‑resistance and resistance‑to‑temperature calculations were checked for agreement with IEC 60751, confirming technical correctness and professional suitability.

Relevant Standards

Temperature range: –200 °C to +850 °C for platinum RTDs.
Interpolation for t ≥ 0 °C: R(t) = R₀ × (1 + A×t + B×t²)
Interpolation for t < 0 °C: R(t) = R₀ × (1 + A×t + B×t² + C×(t‑100)×t³)
Coefficients: A = 3.9083×10⁻³ °C⁻¹, B = –5.775×10⁻⁷ °C⁻², C = –4.183×10⁻¹² °C⁻⁴.
Nominal reference resistance R₀ = 100 Ω for PT100 sensors.

Assessment Summary

The calculator’s displayed formulas and results match IEC 60751 definitions. Testing confirmed its outputs align with both the official resistance tables and results from direct equation evaluation across the full temperature range.

Verification Details

Sample values were compared with IEC 60751 data and independent calculations. Results matched to within 0.01 Ω or better across all tested points.

Test Case	IEC 60751 Value	Calculator Output	Compliance
–200 °C → R	18.520 Ω	18.5201 Ω	Correct
0 °C → R	100.000 Ω	100.0000 Ω	Correct
100 °C → R	138.51 Ω	138.5055 Ω	Correct
400 °C → R	247.09 Ω	247.092 Ω	Correct
850 °C → R	390.481 Ω	390.4811 Ω (850 °C back‑calculated)	Correct

Limitations & User Responsibility

Calculator assumes a nominal PT100 (R₀ = 100 Ω) unless adjusted.
Uncertainty estimates are not provided within the tool.
Users must ensure suitability for their specific calibration processes.

Conclusion: The PT100 RTD Calculator has been independently validated with AI‑assisted review and conforms to IEC 60751 equations and tables. It is suitable for professional calibration work, with users responsible for integration into their own quality systems.