Once you have created a pen group, you can modify the tags belonging to it at any time. To do so, follow these steps:
1. Expand the pen group drop-down list in the Historical Data Viewer page's tool bar (i.e. the drop-down list to the far left in the tool bar).
2. Select the name of the pen group you wish to modify.
3. Click the Tag Selector button. The Tag Selector dialog will open, and the text Currently Editing <Pen Group Name> will appear in its title bar (where <Pen Group Name> is the name you configured for the selected pen group).
4. Use the Select Tag and Remove Tag/Query buttons in the Tag Selector dialog to modify the Selected Tags list until it contains only the tags you wish to belong to the selected pen group.
5. Click the Save Group button. The Save Group dialog opens and displays the name of this pen group.
6. Click the OK button to modify the referenced pen group.
7. Click the Plot button to close the Tag Selector dialog and plot all pens belonging to the group on the graph on the Historical Data Viewer page.