When you click the graphic representation of any analog input or digital input tag, a windowed version of the Historical Data Viewer page opens on the screen as shown below.

Clicking an analog input or digital input tag's graphic representation opens a windowed version of the Historical Data Viewer page that instantly plots the selected equipment process data.
The windowed version of the Historical Data Viewer page opens on top of the application page you are currently viewing, enabling you to view both pages simultaneously. The windowed Historical Data Viewer page is resizable and can be dragged around on the screen, enabling you to view data appearing behind it.
The Historical Data Viewer page is discussed in The Historical Data Viewer Page.
Once the window has been opened, you can continue to automatically trend additional tags, simply by clicking graphic objects representing other analog input tags.
Note: By default, VTS has been configured to open windowed versions of the Historical Data Viewer page when you click the graphic objects for analog input or digital input tags; however, your VTS developer may have configured your application to perform otherwise. Ask your VTS developer for details.