Loading…
Skip to main content
Engineering Toolbox/Thermocouple Reference / ITS-90

Instrumentation & Calibration

Thermocouple Reference / ITS-90

Convert reference temperature and EMF for common base-metal thermocouples, or compensate a measured EMF when the cold-junction temperature is known.

Reference calculator

NIST ITS-90 reference EMF is relative to a 0 °C junction.

Reference EMF relative to a 0 °C junction.

Field use

Reference conversion and CJC troubleshooting.

Use this when checking expected millivolts, validating a calibrator/source value, or resolving a known cold-junction temperature for Types J, K, T and N.

Calculation basis

Reference functions are based on NIST Monograph 175 / SRD 60 and ITS-90.

Reference: E₀ = f(T)
CJC: E₀(Thot) = Emeasured + E₀(Tcold)

This is a reference-function tool. It does not state thermocouple tolerance, calibration uncertainty, drift, wire/connector error, inhomogeneity, installation error or complete loop accuracy.

Continue in Instrumentation & Calibration

View category →
4–20 mA Signal Scaling Convert loop current to percentage of span and engineering units, or calculate the expected mA from a process value. 3–15 psi Pneumatic Signal Convert a standard pneumatic control signal between psi and percentage output without hiding underrange or overrange conditions. Five-Point Calibration Check Evaluate 0, 25, 50, 75 and 100% points against a defined tolerance in percentage of calibrated span. Calibration Error Calculate signed error in engineering units and percentage of span, with a clear pass/fail result against tolerance.