Histogram

A histogram element can be used to visualize an array. The values of the array elements will be represented by bars or lines side by side, indicating the current values of the element by their height.

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The configuration dialog will be opened as soon as you insert a histogram element into a visualization object. A preview is part of the dialog, immediately showing how the element will look as a result of the currently set parameters:

  • Presentation:  Activate one of the options Barchart or Lines.

  • Show horizontal lines: If this option is activated, horizontal lines spanning the diagram will additionally display the scale gradation.

  • No Scaling: If this option is activated, the inserted element cannot get resized.

  • Alarm color: This button opens the dialog ‘Configure alarm’, where you define at which value the bar will be displayed in alarm color and which is the alarm color: Insert the desired threshold value in the edit field and activate one of the Conditions greater than or less than, in order to define whether values higher or lower than the limit value should set off an alarm. Press button Alarm color to open the standard dialog or a target-specific color selection list for choosing the alarm color. Close both dialogs with OK in order to confirm the settings and to return to the main dialog for configuring the histogram.

  • Variable/Scale:  This button opens the dialog ‘Configure scale and variable’, which can be filled like described for the Meter element.

  • Color areas: This button opens the dialog ‘Configure color areas’: Here you can define a separate color for each partition of the scale. See the description of the Meter where the same dialog is available.

  • Bar color: This button opens the standard dialog for choosing a color. Define a color for the bar in normal state (no alarm).

    Define which range of the array should be displayed:

    • Arraybegin: First array element to be displayed (Index).
    • Arrayend: Last array element to be displayed (Index).

  • Barwidth:  Define the width of the bars in percent by the total width available for one bar.

Example:

See in the following picture an example of the online display (bars resp. lines) of a histogram which represents an array arr1 [0..4] of INT. The arraybegin was set to “0”, the arrayend to “4”, the scale start to “-4”, the scale end to “24”, the main graduation was set to “2”, the sub-graduation to “1” and the scale range 0 ““ 8 has got assigned another color (dark grey) than the rest of the scale range. Furtheron the bars should be displayed alarm-colored (blue) as soon as the value of the corresponding array element exceeds “8”. You see the array elements arr1[2] and arr1[3] currently being in alarm state:

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