Overview of the AppEngine object

The AppEngine object is a key member of the core set of AutomationObjects within the ArchestrA system infrastructure. The AppEngine object can be further classified as an Engine Object within the category of System Objects.

The AppEngine is the real-time, schedule-driven execution engine that hosts and executes objects that constitute an automation application. Typically, hundreds or even thousands of other AutomationObjects are deployed to and run on an AppEngine. The AppEngine provides services for managing deployment, undeployment, startup, shutdown, and scheduling of its hosted objects.

Normally, the majority of objects hosted on an AppEngine are ApplicationObjects that represent equipment and devices in the physical world. In addition, the AppEngine is the host for Area objects and for the DeviceIntegration Objects that provide the important interfacing and I/O capability for external devices.

Important! It is recommended that you only deploy up to sixteen engines to a single platform. Deploying more than sixteen engines may deteriorate the system performance.

The AppEngine object provides a set of configuration and runtime attributes for the AppEngine.

Some key aspects of the AppEngine object include:

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

• It hosts and executes ApplicationObjects, DeviceIntegration Objects, and areas. Because the AppEngine object manages the execution of ApplicationObjects, the scan rate of the AppEngine object determines the scan rate of all its hosted Application Objects.

• It contains the logic to set up and initialize 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 runtime diagnostic attributes that can be monitored, alarmed, and historized.

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

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 Attributes Help in the Help file header.