Design the System and System Context

Define System Architecture

The DATAFLOW Designer allows you to define the System- and Software-Architecture of a product (including products for highly regulated industries) using DATAFLOW notation. The architecture is defined within the DATAFLOW Diagram Editor.

DATAFLOW Diagram

Every project contains at least one DATAFLOW Diagram. Each System Component and Active Container added to this diagram creates its own child diagram to define its internal structure.

Diagrams can contain components that are dropped from the toolbox window. The components can be placed inside a diagram. The components function as containers, and child elements (such as ports, timers, etc…) can be dropped onto them to make them a child of this parent element.

The editor also allows you to create channels that connect ports. Those are created by dragging from one port to another.

This chapter describes the typical actions that are performed when defining a system architecture.

Define System Context

When a new project is created, the system context needs to be defined during the first step. The System  is automatically created with the project.

System Context Example

These steps are required to define the System Context of the system that is displayed below:

1. Drag & Drop Box, Text and Image objects from the Diagram Toolbox to the diagram area to describe users, other systems or accessories relevant for the system context.
2. Drag & Drop the required Hardware Interfaces from the Interfaces Toolbox onto the system element.
3. Connect the Box Objects to the Hardware Interface using Hardware Channels.

Example System Context

System Architecture and System Context Items

The following items are available in the Diagram Toolbox to define the system context and model the intended system:

• Common Items

Common items are mainly used for additional description of the model. They are not available for application code generation.

Box (rectangle box with label)

Box Item with Property Inspector Window

Text

Text Item with Property Inspector Window

Image

Image Item with Property Inspector Window

Components

System

The system item represents an abstracted top-level overview of the whole project that should be developed. A ‘System’ item is represented by a box with a blue title bar. The system item is unique and created automatically with the project. System items cannot be added from the toolbox, but the latter represents the whole root diagram. They cannot be deleted, but they can be decomposed, and the position, size, name and its children can be changed. A Target Hardware and one too many Toolchains can be assigned to a System item. No code is generated for System items when triggering the generation of application code.

System (root) item

System Properties

Data

Attribute	Description
Name	System Name
TargetName	The name of the Hardware Target is displayed, if any is assigned (read only).
ToolchainNames	All assigned Toolchains are listed here (read only). See 5.7.1 Add Toolchain
DisableValidationMessage	Warning messages for this element can be disabled.

Documentation

Attribute	Description
Description	A brief description of the system can be inserted here.
DocumentationPath	A path or URL to the system documentation. A placeholder variable <REF> can be used to work with a general path environment. A documentation path is automatically propagated down to all child items. This path can be adjusted for each child if required. E.g., https://doc.mycompany.com/items?_a=edit&id=<REF>&triage=true
DocumentationReference	Reference to the specific item in the system documentation. E.g., 2852 The value in this field replaces the <REF> variable in the documentation path. E.g., https://doc.mycompany.com/items?_a=edit&id=2852&triage=true

Appearance

Attribute	Description
Position	X, y coordinates of the system block in the diagram.
ZIndex	Z-Position of the element.
Width	Width of the interface item.
Height	Height of the interface item (read only).

System Properties

System Component

System Components are used to define the ‘System- and Subsystem-Architecture’. ‘System Components’ can be decomposed further to multiple depth levels until they are small enough to handle. A Target Hardware can be assigned to any system component as long as none of the parent items has a Target Hardware assigned. No code is generated for System Component items when triggering the generation of application code.

Segway Sub-System Architecture using System Components

System Component Properties

System Components have the same properties as systems. See Figure - System Properties

• Hardware Interface

Hardware Interfaces are used to describe the physical parts of the system, how they interact with each other and how they react to physical inputs from users or their environment. An external Hardware Interface is represented by a grey box with an icon for the selected hardware type and the name of the interface. Black lines on both sides indicate that the interface has been inherited from the parent container.

Hardware Interface - Analog Input

Available Hardware Interfaces

The following Hardware Interfaces are available for modeling your system.

Hardware Interfaces

Hardware Interfaces used in System Components

Either hardware Interfaces can be added to a component from the Interface Toolbox or they are inherited from a parent component. All Hardware Interfaces need to be assigned to a component at each level. To ensure a complete architecture and that the code is generated without errors or warnings, all Hardware Interfaces should end up in an active part.

Hardware Interfaces

Hardware Interface Properties

Data

Attribute	Description
Name	Hardware Interface Name
TargetName	Hardware Interface Type selection.
DisabledValidationMessage	Warning messages for this element can be disabled.

Documentation

Attribute	Description
Description	A brief description of the system can be inserted here.
DocumentationPath	Path or URL to the system documentation. A placeholder variable <REF> can be used to work with a general path environment. A documentation path is automatically propagated down to all child items. This path can be adjusted for each child if required. E.g., https://doc.mycompany.com/items?_a=edit&id=<REF>&triage=true
DocumentationReference	Reference to the specific item in the system documentation. E.g., 2852 The value in this field replaces the <REF> variable in the documentation path. E.g., https://doc.mycompany.com/items?_a=edit&id=2852&triage=trueà

Appearance

Attribute	Description
Position	X, y coordinates of the system block in the diagram.
Width	Width of the interface item.
Height	Height of the interface item (read only).

System Component Properties

• Hardware Channels

Hardware Channels are used to visualize the interfaces between different hardware components. No code is generated for Hardware Channel items when triggering the generation of application code.

Hardware Channel Properties Data

Attribute	Description
Name	System Name

Documentation

Attribute	Description
Description	A brief description of the system can be inserted here.
DocumentationPath	Path or URL to the system documentation. A placeholder variable <REF> can be used to work with a general path environment. A Documentation Path is automatically propagated down to all child items. This path can be adjusted for each child if required. E.g., https://doc.mycompany.com/items?_a=edit&id=<REF>&triage=true
DocumentationReference	Reference to the specific item in the system documentation. E.g., 2852 The value in this field replaces the <REF> variable in the documentation path. E.g., https://doc.mycompany.com/items?_a=edit&id=2852&triage=true

Appearance

Attribute	Description
LineColor	Select the line color.
LineArrows	Select the arrow type for Hardware Channels: Bidirectional, Source to Target, Target to Source or None.
LineStyle	Select the line style: solid, dashed, or dotted.
LineThickness	Choose the thickness of the Hardware Channels line.
LabelPosition	Set the x, y coordinates of the label relative to the Hardware Channel position.
HideLabel	Tick the check box if the label should not be displayed.
RoutingMode	Select the line routing mode for the Hardware Channel line. Line Routing Modes
Routing Points	For certain RoutingModes, RoutingPoints can be added by pressing CTRL + Click. The coordinates for these points are stored in here.

Hardware Channel Properties

Designing the System 

To design your system, drag all the required items from the "Diagram Toolbox" to the diagram area.

• Use images or box items to describe surrounding systems
• Use text items to add descriptions to the system or its surroundings

Add System Context Items

• Connect the interfaces, its sourrounding systems and users with Hardware Channels
• Double click the Hardware Channels to describe the intended interfaces

Add Hardware Interfaces and Describe Channels

System Architecture as Result of the Design Process

System Architecture