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[KB127]How to display a variable’s description in a Trend Viewer in historical mode

Tags: Trend viewer, Trends

HMI
14 years ago
By RM
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Applies to:

PcVue version 7.20c onwards.
Summary:

This article describes how to display a variable’s description in a Trend Viewer’s legend area, in historical mode as well as in real-time mode.

Details:

You can configure the Trend Viewer so as to display the Variable Description field as a column in the legend area. Then when the Trend Viewer is in real-time mode, the description of each variable appears. However when it is switched into historical mode, this field is shown as ‘NA’ (non-accessible). That is because the variables lose their real-time subscription at that point, so as to avoid wasteful processing.

Solution

Since version 7.20c it has been possible to preserve a variable’s real-time subscription, and hence the description of the variable, on transition to historical mode. With the mimic in Design mode:

  1. Right-click on the Trend Viewer and select Properties.
  2. In the Advanced tab, tick the option ‘Keep real time variable subscription in historical mode’.

 

Trend_display_properties_dialog_keep_sub

  1. Click on OK to apply the setting and close the dialog.

The variables’ descriptions are then displayed in the legend in both real-time and historical modes.

Trend_display_legend_historical

Further information

For advice on configuring the Legend, see the topic ‘Configuring the Trend Display Legend Area’ in the Supervisor’s Help.

Created on: 05 Nov 2010 Last update: 13 May 2024