Calculate Model Indexes
Sigmafine includes indexes that help you gauge the overall quality of the reconciled results. These data indexes equal zero when all measurements are true physical values and the flow Model correctly represents plant operation. Data quality is gauged by measuring data flaws. The best data quality has zero imperfections.
These data indexes, called DX indexes, are calculated with the measured and the reconciled data, and provide a means to monitor the overall quality of the data in the model. This allows you to quickly see if the data quality on the new Case has changed from the previous data quality history and to see results of improvements, such as meter recalibration, lab data correction.
The DX indexes are based on established principles and common plant operating practices. Root of the mean of the squares (RMS) averages for five classes of data support the central DX indicators. All five indexes are calculated in a Case run:
- DX0 - Non-Redundant Quantity Indicator
- DX1 - Imbalance Indicator
- DX2 - Reconciled Correction Indicator
- DX3 - Tolerance Indicator
- DX4 - Reconciled Difference Indicator
Indexes DX1 – DX4 depend on the following RMS (root of the mean of the squares) averages:
- RMS of Redundant Flows – Redundant metered flows and tank gauge differences.
- RMS of Imbalances – The initial imbalance at all material balance points: processes, tanks, headers, and other nodes.
- RMS of Corrections - Corrections to the redundant measured flows that bring the data into material balance. Note that there is insufficient information to correct non-redundant flows.
- RMS of Tolerances – The standard measured error tolerances effective for the current redundant flows. Typically, the SME tolerance is half the tolerance used for the TESTn evaluations.
- RMS of Reconciled Flows – The results of correcting the measured flows.