Accessing Xentara Elements

Table of Contents

• Attributes
• Events
• Tasks

Each element in the Xentara model exposes a number of different member objects that are used to interact with the element.

Attributes

Each element in the Xentara model exposes a number of attributes. An attribute is a value related to the element that can be read or written by other elements. Each attribute has a attribute name used to identify it.

All Xentara elements expose at least the following three attributes:

Attributes

key	The element’s primary key.
name	The element’s name. The name is the last component of the primary key.
UUID	The unique UUID of the element.
type	The element’s element type.
category	The element’s category.

Each element type may define any number of additional attributes, each with a unique name. Please refer to the documentation of the specific element type for a list of additional attributes it provides.

Like the element itself, each of a element’s attributes has a primary key. The primary key is simply the primary key of the element followed by the name of the attribute, separated by a period. The name attribute of a element with the key Building.Rack.DAQ.Status would simply be Building.Rack.DAQ.Status.name, for example.

Events

Each element in the Xentara model may expose any number of events. An event allows an execution pipeline to be executed when something happened. An event may, for example, be triggered when the value of one of the element’s attributes changes.

Each element may define any number of different events, each with a unique name. Please refer to the documentation of the specific element for a list of events it provides.

Like the element itself, each of a element’s events also has a primary key. The primary key is simply the primary key of the element followed by the name of the event, separated by a period. An event named changed of a element with the key Building.Rack.DAQ.Status would have the primary key Building.Rack.DAQ.Status.changed, for example.

An element additionally exposes a change event for each readable attribute that is raised whenever the attribute’s value changes. The change event has the same name and primary key as the corresponding attribute. Attribute that can never change (like the “name” attribute) still have an associated change event, but the change event is never raised. Write-only attributes also have change events, but they are likewise never raised.

Tasks

Each element in the Xentara model may expose any number of tasks. A task is an action that can be placed into an execution pipeline, and executed either using a timer or an event. Tasks may perform all sorts of different actions, including, but not limited to:

• Sending a poll command to a device to read some I/Os
• Sending data to the cloud
• Performing a simulation step in a simulation component
• Running an iteration of an AI model
• Updating a display
• Executing an iteration of the control loop of a PID controller

Each element may define any number of tasks, each with a unique name. Please refer to the documentation of the specific element for a list of tasks it provides.

Like the element itself, each of a element’s tasks also has a primary key. The primary key is simply the primary key of the element followed by the name of the task, separated by a period. A task named poll of a element with the key Building.Rack.DAQ would have the primary key Building.Rack.DAQ.poll, for example.