Xentara v2.0.4
User Manual
Xentara Elements

Table of Contents

Everything in Xentara is described using an element in the Xentara model tree. Examples for things that are described by a Xentara element include, but are not limited to:

  • data points,
  • hardware devices (like EtherCAT devices, Modbus devices, PLCs, etc.),
  • communication busses (like a serial port used for Modbus RTU),
  • smart sensors,
  • I/O cards,
  • control, automation, and simulation components (like FMUs or Soft-PLC programs),
  • AI models
  • northbound connections (like connections to cloud services or time-series databases)

There is also a special element type called an element group, that groups together other related elements, like e.g. all the element belonging to a single machine or to a single production line. Groups can be nested, meaning that a group can itself contain other groups. This allows you to organize all the elements into a hierarchichal semantic tree structure, called the Xentara model tree.

Identifying Elements

Xentara elements can be identified in two ways:

  • by its primary key, a text string describing its position in the Xentara model tree. The primary key consists of components separated by periods (“.”). The element describing the x acceleration of the arm of a certain cobot could have the key “Station 12B.Cobot.Arm.X Acceleration”, for example.
  • by a unique UUID (“Universally Unique IDentifier”) that never changes, even if the semantic tree is refactorted, and elements or element groups are renamed or moved around in the tree. UUIDs are 128 bit identifiers in the form “e9aa8b54-1654-4942-82c1-8d83ed8bafda”. UUIDs are sometimes referred to as “GUIDs” under Windows.

Element Types

Each Xentara element has an element type. The element type describes exactly what the element is used for. Element types include types for all the built-in element types. Additionally, each Xentara skill has its own element types. The built-in Signal Generator skill, for example, provides the element types “signal generator sampler” and “signal generator signal” for samplers and signals, respectively.

Element Categories

Additionally to the element type, each element has a category. The element category is similar to the element type. However there are only a fixed number of predefined categories, and all skill elements are assigned to one of these qualities. This allows you to check the category of an elements without having to know exactly what types the corresponding skill provides. This is useful, for example, for listing all types of data points including skill data points, or for listing all types of I/O devices.

Xentara supports the following element categories:

Category Description
root element

The anonymous root element.

The anonymous root element is the parent element of all top-level elements in the model.

element group An element group
data point A data point or a skill data point
timer A timer
execution track An execution track
execution pipeline An execution pipeline
device A skill element representing a physical or virtual device. This includes external and internal hardware devices, and virtual devices like System health services or a Xentara Signal Generator.
sub device A skill element representing a sub device of another device.
device group A skill element representing a group of related devices, like a serial port or network interface that can have multiple attached devices.
data point group A skill element containing a group of related skill data points, like a structured variable in a PLC.
transaction A skill element representing a southbound or northbound data transcation, like for example an I/O transaction.
microservice A skill element representing a microservice, like an FMU or soft-PLC runtime, or any other sort of control logic.
AI A skill element representing an artificial intelligence model or engine. This can be either an AI model running directly in the plugin, or an interface to an external AI system.
data storage A skill element representing a data storage service, like an InfluxDB or clarify.io database.
external interface A skill element providing a northbound interface, like a Xentara Web Service or a Xentara OPC UA Server. This also includes interfaces to other data services, like an MQTT broker, a Sparkplug application, or a UI or visualization tool.
special purpose A skill element representing anything that does not fit into any of the other categories.

Element Members

Each element in the Xentara model exposes a number of different member objects that are used to interact with the element. The individual element members are described in Accessing Xentara Elements.