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The TrendPlot tab is available in View 1 (opening screen). This plot shows the data based on the S-IDAP algorithm.
The example above shows the following items:
The plot on the right side is from the selected row in the Results tab or or Measurements tab. In this example from Equipment “Eq_Pipe1”, Circuit “1000”, SubCircuit “1000”, CML “05EA” and MP “MINIMUM”.
The dark blue line (not seen here) at 9.7 mm represents the renewal thickness.
The (good) measurements are displayed as blue dots.
The predictions are displayed as blue dots, the accompanying uncertainty bands (purple vertical lines) can be interpreted as prediction intervals for single future measurements. These are based on the updated confidence in the model and the supplied accuracy of the Wall Thickness measurements.
After each measurement, the expected Wall Thickness and Corrosion Rate, given the information up to that point, are calculated. The updated Wall Thickness and Corrosion Rate are displayed as the starting point and the slope of the line to the next measurement.
Anomalies are displayed as red dots. It is called an Anomaly because the posterior probability of model 1 being true is low.
When an Anomaly is found (or declared) a number appears on the purple error band: a 2 means a wrong measurement, a 3 a change in level and a 4 a change in slope (Corrosion Rate).
The first prediction interval after an Anomaly is a lot wider than the one before, caused by the increased model accuracy.
The green dots correspond to the estimated Corrosion Rates where the scale is given on the right hand side y-axis.
Right click on a reading (blue dot) to open the sub-menu (Good, Verified, Ignored).
An ignored reading is displayed as a pink dot (see example below)
Historical readings are colored black (see example below). The green dot represents the renewal.
To learn more about trendPlots see PEI Circuits - Details Page.