S-IDAP TrendPlot Tab

The TrendPlot tab is available in View 1 (opening screen) / View 2.  This plot shows the data based on the S-IDAP algorithm.

TrendPlot Legend

To learn what the colors and symbols in the TrendPlot represent:

• Click the Legend button.

The example above shows the following items:

• The plot on the right side is from the selected row in the Results tab or Measurements tab. In this example from Equipment “INSP60_Equipment_Pipe2”, Circuit “1000”, SubCircuit “1000”, CML “05EA” and MP “MINIMUM”.

• The dark blue line at the bottom represents the Minimum wall thickness.

• The normal Wall Thickness measurements are displayed as blue dots.

• The 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 (Outliers) are displayed as red dots. It is called an Anomaly because the posterior probability of model 1 being true is low.

• When an Anomaly (Outlier) 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 decreased model accuracy.

• The green dots correspond to the estimated Corrosion Rates where the scale is given on the right hand side y-axis. When you point your mouse to an axis you will also see the axis label (below the CR label is displayed).

• An ignored reading is displayed as a pink dot with an “I“ label (see example below).
  

  

• Historical readings are colored black (see example below). The green dot represents the renewal.
  

Verifying and Mitigating readings

To verify or mitigate a reading:

• Right click on a reading (blue / red dot) to open the sub-menu (Good, Verified, Ignored, Mitigation).

• From here you can mark a reading as Good / Verified / Ignored or you can Mitigate the CML with a CAIR. (You can also do this verification from the Measurements tab.)

  

• To learn more about TrendPlots see PEI Circuits - Details Page.

Zooming in

To zoom in or out of a specific section of the plot:

• Click the zoom button.

• Then move the markers to the desired positions.