Uncertainty according to the GUM. Never better than accredited.
SimplyCal maps the complete uncertainty budget according to EURAMET cg-18 (V4.0) and the GUM — calculated automatically from the measurements. On the calibration certificate, the uncertainty is never stated smaller than your accreditation permits.
Reported measurement uncertainty = max( U(E), your CMC )
Complete uncertainty budget
Every relevant contribution enters the budget in accordance with EURAMET cg-18 — as Type A (from the measurement series) and Type B (from the instrument data).
- Repeatability, eccentricity, resolution (d₀ / dL)
- Air buoyancy, material density & density uncertainty
- Temperature, tare, creep and hysteresis effects
Coverage factor k — determined correctly
Instead of simply applying k = 2 across the board, SimplyCal determines the coverage factor properly: k = 2 in the standard case (normal distribution, sufficient repetitions), otherwise via the effective degrees of freedom (Welch-Satterthwaite, t-distribution).
- GUM-compliant combination of the uncertainty contributions
- Welch-Satterthwaite for small samples
- Special cases for rectangular/trapezoidal distribution
Never better than your CMC
In the CMC table you store your CMC (calibration and measurement capability) – absolute plus relative, per load range and weight class. If a matching CMC is stored for the calibration, the certificate shows the larger of the calculated value and the CMC.
- CMC table: absolute + relative per load range and class
- CMC as automatic lower limit
- Accreditation profile with validity period and location
Two uncertainties, one certificate
SimplyCal separates the uncertainty of the calibration from the uncertainty of the balance in practical use — both evaluated graphically.
- U(E): uncertainty of the calibration
- U(W): uncertainty in use, global & approximated
- Approximation line with formula directly in the chart
Conformity assessment with decision rule
Tolerance monitoring can be carried out with or without taking measurement uncertainty into account — configurable separately for accredited and factory calibration.
- Decision rule per calibration type
- Tolerance monitoring with/without uncertainty
- Live temperature & plausibility limits with abort
Normative basis
The calculation formulas are anchored directly to the relevant sections of the standards — the calculation core is validated.
- EURAMET cg-18 V4.0 (incl. 7.1.1 / 7.1.2)
- GUM · OIML · ASTM
- Air density according to the CIPM formula
Related topics
Measurement uncertainty that auditors like to see.
We will show you the complete uncertainty budget on your own balances — from the measurement to the accredited certificate.