Screen

The Screen is where you create flexible and interactive diagrams and layouts for your users. By configuring a screen with controls and tools, you can create a data-rich visualization of devices, facilities, and other elements in your CygNet environment, convey information about the state of a process via charts, grids, gauges, images, and other data-visualization tools, and design workflows where objects are scripted to accept and implement an operator's control instructions in run mode. The Canvas screen is where you create the HMI for your users in the field and is analogous to TheFrame/TheView in CygNet Studio.

Canvas screens and objects share the same configuration properties. Screens (and objects) support a broadcast feature that allows you to manipulate and pass the SiteService and facility from one screen to another using the Canvas user interface without writing script. Screens (and objects) support navigation by facility to link to a facility's associated screen, using one of six navigation modes. Screen hyperlinking is supported via script. Screens and objects support a default or on-demand chart, which can be invoked anytime from a Canvas or Canvas View screen in design or run mode in the form of a separate dialog box. The default chart supports configurable date ranges, both relative and absolute; live data updates at a configured interval allowing the chart to trend data at a real-time pace. Other configurable screen features include: background color, custom color palette for point state, pan zoom control, title, layout grid (color, height, and snap action), and whether the alarm notifier is visible on the screen when opened in Canvas View and Canvas View Lite.

Configuring Screens

See Creating New Screens and Objects for more information about creating new objects.

Property Inheritance

Property Inheritance

Property inheritance is a widely used concept in Canvas. The application supports an explicit relationship between screens, objects, and controls, where certain property values, such as SiteService and facility tags, are passed from one element to another via an inheritance framework. Screens, objects, and controls can be configured as property senders or property receivers and provide configuration options where you can explicitly define the source of the SiteService and facility. Depending on how you have your screens, objects, and controls set up, the SiteService and facility may come from any one of the following sources:

• from itself — indicated by selecting <Self> and then explicitly configuring the property
• inherited from the screen — indicated by selecting Screen, which is always present as a sender
• inherited from another control — indicated by selecting the Name of the sending control

Broadcasting

Screens and objects support an additional notification option to broadcast their SiteService and facility selection changes to other open screens running in the Canvas or Canvas View application. If configured, a <Broadcast> option is available to source the screen's SiteService and facility properties from another open screen.

For example, a text tool can be configured to get its facility from the screen and the screen can be configured to get its facility from a tag chooser. Or Screen_A might source its facility from Screen_B, which gets its facility from a tag chooser.

Receiver or Sender

The screen supports property inheritance, both as a receiver of its SiteService and facility from controls on the screen and from the other screens, and as a sender of its SiteService and facility to other controls on the screen and to other screens:

This allows users to create dynamic screens that can be driven by a SiteService or facility configured on a different screen. See Interscreen Communication for more details about this option.

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