Starting the Control
In PI Vision, click on "Assets" at the top left to expand the corresponding area.
In the upper area click on "weruSPCHistogram" to select the control.
Then you can search for the desired PI tag and add it to the display using Drag&Drop.
Functionality of the Control
The control accepts all data points in the configured time period and sorts the values independently of time into a configurable number of intervals. A value range of +/- 5 sigma from the average value is displayed. The black line corresponds to the normal distribution. The blue coloring in the background corresponds to that from the SPC Trend Control.
See SPC Trend Documentation for more details!
Under "Plot Time" you can select whether the PI Vision time range or statically the last n data points are to be used. "Number of bins" defines how many sections the x-axis will be divided into. "Sigma Calculation" offers two different methods to calculate sigma.
Under Center Line, another value can be defined as the center line instead of the average. Upper and Lower Control Limit define the value of +/- 3 Sigma. Upper and Lower Specification Limit have no influence on the calculations and define the specification limits.
All five values can be specified statically as a number or dynamically as PI Tag (format \\piserver\pitag).
Changing the Size of the Control
In case that the legend or some part of the control is not visible, it is necessary to adjust the size of the control. To do so, the first step is to change into edit mode (Icon in the upper right corner) and in a second step to click on the control. The eight appearing dots around the control can be used to adjust the size that everything is visible.
Removing the Control
Before removing the control it is necessary to switch into edit mode (Icon in the upper right corner). Thereafter it is possible to click on the control and press the delete key to remove the control.