Configure pen details and options

After you add a pen and configure the expression or reference for the pen(s), you can set details and options for how the pen shows information on the trend chart. Pen details include the description, units, minimum and maximum for the pen. Pen options include the pen color, width, style, plot type, number of decimal places, format, and retrieval mode.

The default values for the pen details are formed by appending .Description, .EngUnits, .TrendLo, and .TrendHi to the pen expression. For example, if the pen expression is Me.PV for a field attribute named PV created on the user defined object, the default pen details are Me.PV.Description, Me.PV.EngUnits, Me.PV.TrendLo, and Me.PV.TrendHi. These are generally the best expressions to use for historized attributes. (If the expression is empty or invalid, the Trend Client uses default values of 0 and 100 for the minimum and maximum at run time.)

Note: For some input boxes on the configuration screens, you can specify if the configuration is a static value or a reference by setting the input mode. An input mode icon appears to the left of these boxes. Use static mode input to specify a literal static value such as "Temperature" or 3.141. Use reference mode to specify a reference to an attribute or symbol property such as Tank_001.PV. You can enclose static string values with double-quotes (such as "Description:" or "+Tank_001.Desc") with or without references in Reference mode. When you are in reference mode, you can also click the ellipsis button to the right of the box to show a selection tool such as the Galaxy Browser or the Tag Picker.

A line curve (plot type Line) is best suited for charting continuously-changing analog data. A step-line curve (plot type Step) is best suited for discrete data and box for analog data that is not continuous. When you select a plot type of Auto, the curve type is determined as follows:

• For tags retrieved from Historian 9.0 (or higher), the type is based on the tag’s effective interpolation setting. Tags that use stair-step interpolation are trended as a step line, and tags that use linear interpolation are trended as a line.

• For all other tags, the curve type is based on the tag type: step line for integer tags, and line for real tags.

The following illustration shows the same data drawn using each type of curve. The line curve is shown in green, the step line curve is shown in orange, and the point curve is shown in red.

To configure the options for a pen

1. Select the pen you want to configure.

2. In the Pen Details area, configure what the pen shows.

   Description	The pen’s description. The expression is evaluated and the result is used for the pen's description in the pen list (the legend) below the chart itself.
   Units	The unit to chart in. This is the plot scale, rather than an instrument scaled from a percentage to engineering units.
   Min	Type the minimum for the pen’s range.
   Max	Type the maximum for the pen’s range.

3. In the Pen Options area, configure how the curve looks in the chart for the selected pen.

   Color	The line color of the pen. Click the colored square to select the color from a palette or define a custom color.
   Width	The thickness of the trend curve. Valid values are 0 through 10.
   Style	The style of the trend curve; for example, a solid or dashed line.
   Plot type	The type of trend curve to draw. Options are Line, Step line, Point, and Auto.
   Decimal Places	The number of decimal places to show for the data value. This applies only to analog tags. Valid values are 0 through 15.
   Format	The way the values for the pen appear, either in decimal format or scientific format.
   Retrieval Mode	The data retrieval mode, either Cyclic, Full, or Application Setting.