Thermistor / RTD Lookup THERMISTOR

Where the values come from. Each R/T table is generated from a small set of curve parameters — β and R25 for the NTC thermistors, the parallel shunt for the linearized 10K curves, R0 and a temperature coefficient for the RTDs. The Pt100 and Pt1000 tables come from the IEC 60751 Callendar–Van Dusen polynomial (the international standard). Auditing the parameters is what makes a 500+ cell table trustworthy in one pass, instead of one row at a time.

Sources verified against (2026-05 pass). 10K Type II, 10K Type III, and 10K Type 5 (TAC) — BAPI 10K-2 / 10K-3 / 10K-3(11K) output tables, cross-checked against US Sensor "Curve G", Sontay's Compatibility Chart, and Vector Controls' multi-curve reference. 20K and 3K — Vector Controls and Sontay. 1K Balco — a Schneider EcoStruxure Building Operation resistance chart plus the ACI BALCO datasheet. Pt100 and Pt1000 — IEC 60751:2008 directly, cross-checked against Vector, Sontay, Fluke's table generator, and pt100.de. Where multiple sources disagreed, I consulted with a second tech before settling on a curve.

What's still nominal. The Johnson Controls 10K + 8.7K-shunt curve is the one type without a public R/T table — the canonical TE-6300 Product Bulletin URL redirects to a docs-portal landing page. It's modeled as a 10K Type 2 element in parallel with 8.7 kΩ, which is folklore-confirmed but datasheet-unverified. If you have a known-good JCI sensor with calibration data, that's the better reference.

Use as a reference, not for calibration. A single-β model approximates a Steinhart-Hart curve; the fit is within roughly 1 °F across 32–150 °F (the BAS operating range) and degrades to 2–5 °F of equivalent temperature error at the −40 °F extreme for the bare 10K curves. Pt100 and Pt1000 are governed by the international standard and match it exactly. For calibration-grade work, measure your sensor directly against a known-good reference at the working temperature — don't trust any published table, ours or anyone else's, blindly.