About the ViewEngine Object

A ViewEngine object is a simplified version of an AppEngine object. A ViewEngine object hosts only OMI ViewApp and InTouchViewApp objects, and does not support redundancy.

The ViewEngine object does not need to be running in order for WindowViewer to execute its scripts or access process data.

The ViewEngine object can host AppServer scripts and attributes. The ViewEngine scripts continue to run when WindowViewer is shut down.

The ViewEngine object provides a set of configuration and run-time attributes for the ViewEngine.

Some key aspects of the ViewEngine object include:

• It is assigned to and deployed to a WinPlatform object.

• It hosts and executes OMI ViewApps and InTouchViewApps. The scan rate of the ViewEngine object determines the scan rate of all its hosted ViewApp objects.

• It contains the logic to set up and initialize ViewApp objects when they are initially deployed and started, so that they can communicate with other objects within the Galaxy.

• It contains its own set of run-time diagnostic attributes that can be monitored, alarmed, and historized.

• The historian can be specified as part of the ViewEngine configuration. All ViewApp objects that the ViewEngine object hosts will use this historian.

Because

• A ViewEngine object will host only a few ViewApp objects,

• InTouchViewApp objects only serve as a proxy for InTouch tags.

You may

• not need to use the many historization and alarm options of the ViewEngine object.

• want to use a shorter ScanPeriod on the ViewEngine object to minimize the latency of value updates in the hosted ViewApps.

For general information on objects, including relationships, deployment, and alarm distribution, see the Integrated Development Environment (IDE) documentation.

For information on configuration options of object scripts, attributes, or features, click Object Help in the Help file header. .