History & Statistics
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This module shows the statistical analysis for each measurement, visualizes the history of the corresponding measured values and provides a histogram. The statistical key figures are calculated for each measurement for all groups to allow the comparison of measurements within different groups. The history diagram also allows the graphical comparison between groups. The results can be easily exported in different formats.
Select the desired measurement and group. The view is adjusted accordingly.
To create an MSA type 1 report, press Report Wizard.
Note: Please note that the diagrams and tables are located in dock panels, which can be arranged dynamically on the screen and may be hidden.
This table shows the statistical analysis values (MSA type 1) for the selected group and measurement. The page supports two different views: Group First / Measurement First (Default). Depending on the selected view, the table shows either a comparison of the groups based on the measurement or a list of all measurements for the selected group.
Meaning of the columns:
Count
Total number of measurements
CountValid
Number of measurements without NaN or INF values
CountError
Number of measurements with step status "Error"
CountDone
Number of measurements with step status "Done"
CountFail
Number of measurements with step status "Failed"
CountPassed
Number of measurements with step status "Passed"
CountTerminated
Number of measurements with step status "Terminated"
Avg (or Xg)
Arithmetic average of all measurements
SUM(measurements)/Count() without NaN
Min
Minimum value of all measurements without NaN
Max
Maximum value of all measurements without NaN
LSL
Lower specification limit
from test step (if not unique, the highest found lower limit will be used as a surrogate value)
USL
Upper specification limit
from test step (if not unique, the lowest found upper limit will be used as a surrogate value)
T
Tolerance
USL - LSL
Xm
Nominal value
Average of LSL and USL
Sg
Sigma
Corrected sample standard deviation (using N-1)
Bi
Bias / Systematic Error
Xg - Xm
Cg
Repeatability / Gage capability
((CgNumerator * T) / (CgDenominator * Sg))
Gage capability (biased)
(CgkNumerator * T - Abs(Bi)) / (CgkDenominator * Sg)
Cp
Capability of process
T / (6 * Sg)
Cpk
Critical process capability
Min((USL - Avg) / (3 * Sg) , (Avg - LSL) / (3 * Sg))
%EV
Reliability - Equipment Variation
((EvPercNumerator * Sg) / T ) * 100
%K
(2 * (Xm - Xg) / T) * 100
%RE
Resolution
RE / T * 100, where RE is the minimum distance between any measurements (but not 0) and without NaN
Attention: There is no uniform calculation rule for the values Cg, Cgk and %EV. They are therefore calculated using configurable parameters (shown in italics)! Make sure that the selected parameters correspond to the specifications of your employer / your application! The values can be changed in the application settings. The changes take effect immediately, a recalculation is not necessary.
Here is a short overview of the usual settings for Cg and Cgk in different standards and companies. Data without guarantee! In case of doubt, please ask the company for the parameters used!
MSA 3:2002
(0,2 * T) / (5.15 * Sg)
(0,1* T - |Bi| ) / (2,575 * Sg)
Cg >= 1,33
GM, Bosch, MSA 4:2010
(0,2 * T) / (6 * Sg)
(0,1* T - |Bi| ) / (3 * Sg)
Cg >= 1,33
BMW, Q-DAS GmbH, VW / Audi, VDA 5 (09/2010)
(0,2 * T) / (4 * Sg)
(0,1* T - |Bi| ) / (2 * Sg)
Cg >= 1,33
Ford
(0,15 * T) / (6* Sg)
(0,1* T - |Bi| ) / (3 * Sg)
Cg >= 1,0
Ford
0,15 * σProcess / Sg
(0.45 * σProcess -|Bi| ) / (3 * Sg)
Cg >= 1,0
This view shows all measurement values available for the selected measurement in a dynamic diagram. The values can be arranged by timestamp, global index, index group or serial number.
Certain elements can be shown or hidden. These include markers, the diagram legend and the limit values. The area between the lower specification limit and the upper specification limit can be filled optionally. Also the limit errors can be highlighted to get a quick overview of all errors.
The diagram also supports various views, display options and X-axes:
Single: Only graph for the selected group is shown
All-in-one: The graphs of all available groups are superimposed. Here it is recommended to switch off the limit value display. With the checkboxes of the legend you can hide unwanted graphs
Stacked horizontally: The graphs of all groups are displayed side by side in their own diagrams
Stacked vertical: The graphs of all groups are displayed one below the other in their own diagrams
With the mouse wheel or by dragging an area with the mouse the shown section of the graph can be enlarged / zoomed. After zooming, the visible section can also be moved with the mouse. For "stacked" views, the zoom is applied to all diagrams simultaneously. By clicking the "Reset Zoom" button the view can be reset to 100%.
Display options
Lines (directly connected points)
Points
Bars
Spline (Interpolated Curve)
Steps (points connected as steps)
X-Axis Options
Index Global: X-axis is oriented according to the index position of the execution in a global comparison (sorted by execution start)
Index Group: X-axis is oriented according to the index position of the execution within the selected group (sorted by execution start)
Timestamp: X-axis represents the absolute time
Serial Nr: Here the points are sorted according to the serial number of the test object
Watchlist Function Clicking on a measured value in the diagram opens a detail table that displays all available information for the corresponding test step and test execution. Within this window, an execution can be enriched with comments and added to the watchlist to mark it for further analysis. The corresponding report can also be opened.
Representation
The histogram diagram shows the statistical distribution of measured values of the selected measurement. Value ranges are automatically grouped and the number of measured values that lie within these limits are displayed as bars. Within these bars the status is also grouped by Passed (green) and Failed (red).
The groups are formed around the mean value in the range +/-6 sigma. The number of groups can be defined in the application settings. If the number is set to 0, the system calculates a reasonable value depending on the number of measured values.
The histogram also shows the expected normal distribution around the arithmetic mean (Xg/Avg), as well as the critical limits +/-3 sigma and, if possible, the limits LSL and USL and the nominal value (Xm). The latter depend on whether the limits within the measurement series are unambiguous and valid.
Treatment of inconsistent limits
If the limits within the series differ from each other, it is usually not possible to calculate values that depend on the lower and upper specification limits (Nominal, T, Cg, Cgk, Cp, Cpk, %EV, ...). In this case, the narrowest occurring limits are used as a substitute for calculation and the values are displayed in the table in italics. The found value ranges are displayed in the histogram as bands, which mark the largest and smallest occurring limit values:
Treatment of extreme values
Values outside the +/- 7-sigma range are visualized in the histogram in two special groups as gray bars. Values contained here (independent of the bar width) then lie outside the range of Xg +/-7 sigma:
This view shows all measured values in a sortable and filterable data table. The values can be sorted by clicking on a column header. Additionally, each column header has a symbol for filtering the values. In the lower area, sum information such as Min, Max, Avg is offered for selected columns.
This button starts a dialog that helps to select the contained measurements and groups for the report.
The selected composition can also be saved and reloaded. Click on Show Preview to open the preview of the report. From here, the Export button can be used to save the file in various target formats (PDF, Word, Excel, HTML, CSV).
Pressing this button opens the currently selected measurement including all measured values, diagram and histogram as preview without further configuration. With the Export button, the document can be saved in various formats (PDF, Word, Excel, HTML, CSV).
The Export Table button allows the selected measurement to be exported in CSV format.
