Using CitectSCADA > Defining and Drawing Graphics Pages > Understanding Object Types > Trend properties

Trend properties

Trends have the following general appearance properties:

Cluster Name

The name of the cluster that runs the trends being graphed. Each trend graph can only communicate with one cluster, so you cannot mix trends from multiple clusters on a single trend graph.

Note: To mix trends from different clusters on a single trend graph you will need to use Process Analyst.

If there is only one cluster, or, the client is connected to only one cluster, this property can be left blank and the value of the single connected cluster is inferred.

If the client is connected to more than one cluster, then this field needs to be specified.


The pens (including color) to be displayed on the graph (31 characters maximum). You can use up to eight pens.

Double-clicking a selected pen or clicking Edit allows you to change the trend tag and pen color. To insert a trend tag, click Wizard to display theInsert Trend dialog box.

If more than one trend tag is displayed in a trend window and each has a different sample period, the trend with the smallest sample period is used as the general display period.

Note: If the trend object is part of a group, part of a pasted Genie or symbol, or part of the page's template, you can still access its properties: hold down the Control (CTRL) key and double-click the object. Alternatively, choose Goto Object from the Tools menu, click the object, then click OK. Be aware, however, that if it is part of a pasted Genie or symbol, or part of the template, you cannot edit existing pens, only new ones.

If you are configuring an SPC control chart, you need to add a suffix to the trend tag to indicate the type of SPC. There are SPC templates that are easily configured through Genies. Use the Genies rather than defining these trend tags for yourself.The following table lists available SPC types:

SPC Definition

SPC Type

<tag name>.X

Mean of raw data in a subgroup (X - bar)

<tag name>.XCL

Center line of X - bar

<tag name>.XUCL

Upper control limit of X - bar

<tag name>.XLCL

Lower control limit of X - bar

<tag name>.R

Range of raw data in a subgroup (R - bar)

<tag name>.RCL

Center line of R - bar

<tag name>.RUCL

Upper control limit of R - bar

<tag name>.RLCL

Lower control limit of R - bar

<tag name>.S

Standard deviation of raw data in a subgroup (S - bar)

<tag name>.SCL

Center line of S - bar

<tag name>.SUCL

Upper control limit of S - bar

<tag name>.SLCL

Lower control limit of S - bar

where <tag name> is any trend tag, for example:

Pen 1


Pen 2


Pen 3


Pen 4


If you are using the PageTrend() function to display this trend page, leave these fields blank.

Display Trend Types as Periodic

When selected, enables trend pens (both periodic and event) to be displayed as periodic. Event and periodic trend data can then be displayed on the same graph. If this box is not selected, event and periodic pens have different styles and needs to be displayed on separate graphs.

Note: This option is set by default in the predefined templates designed for use with periodic trends. It will only need to be enabled for customized templates.

[Samples] Number of samples (5 Chars.)

The number of samples (1-32767) you can display in your trend window without scrolling (i.e., the width of your trend object). The default depends on the number of pixels per sample and your display resolution. The width of a trend object is equal to Pixels per sample x Number of samples.

Note: For a meaningful trend graph, make Pixels per sample x Number of samples less than the width of the display. For example, an XGA screen has a width of 1024 pixels. If you use 10 pixels per sample, 102 samples can be displayed on the screen without scrolling.

[Samples] Pixels per sample (2 Chars.)

The display width of each sample. The width of a trend object is equal to Pixels per sample x Number of samples. The default is 1 pixel.

Click Clear Property to clear property details, and disable the property. To define other properties for the object, click the relevant tabs.

For help on the remaining properties tabs, see Defining Common Object Properties.