systemcomposer.analysis.Instance

Class that represents model element in analysis instance

Description

The Instance class represents an instance of a model element.

Related classes include:

• systemcomposer.analysis.ArchitectureInstance

• systemcomposer.analysis.ComponentInstance

• systemcomposer.analysis.PortInstance

• systemcomposer.analysis.ConnectorInstance

Creation

Create an instance of an architecture.

instance = instantiate(model.Architecture,'LatencyProfile','NewInstance', ...
'Function',@calculateLatency,'Arguments','3','Strict',true, ...
'NormalizeUnits',false,'Direction','PreOrder')

Properties

Name — Name of instance

character vector

Name of instance, specified as a character vector.

Example: 'NewInstance'

Data Types: char

Object Functions

getValue	Get value of property from element instance
setValue	Set value of property for element instance
hasValue	Find if element instance has property value
isArchitecture	Find if instance is architecture instance
isComponent	Find if instance is component instance
isConnector	Find if instance is connector instance
isPort	Find if instance is port instance

Examples

Analysis of Latency Characteristics

This example shows an instantiation for analysis for a system with latency in its wiring. The materials used are copper, fiber, and WiFi.

Create a Latency Profile with Stereotypes and Properties

Create a System Composer profile with a base, connector, component, and port stereotype. Add properties with default values to each stereotype as needed for analysis.

profile = systemcomposer.profile.Profile.createProfile('LatencyProfile');

% Add base stereotype with properties
latencybase = profile.addStereotype('LatencyBase');
latencybase.addProperty('latency','Type','double');
latencybase.addProperty('dataRate','Type','double','DefaultValue','10');

% Add connector stereotype with properties
connLatency = profile.addStereotype('ConnectorLatency','Parent',...
'LatencyProfile.LatencyBase');
connLatency.addProperty('secure','Type','boolean','DefaultValue','true');
connLatency.addProperty('linkDistance','Type','double');

% Add component stereotype with properties
nodeLatency = profile.addStereotype('NodeLatency','Parent',...
'LatencyProfile.LatencyBase');
nodeLatency.addProperty('resources','Type','double','DefaultValue','1');

% Add port stereotype with properties
portLatency = profile.addStereotype('PortLatency','Parent',...
'LatencyProfile.LatencyBase');
portLatency.addProperty('queueDepth','Type','double','DefaultValue','4.29');
portLatency.addProperty('dummy','Type','int32');

Instantiate Using Analysis Function

Create a new model and apply the profile. Create components, ports, and connections in the model. Apply stereotypes to the model elements. Finally, instantiate using the analysis function.

model = systemcomposer.createModel('archModel',true); % Create new model
arch = model.Architecture;

model.applyProfile('LatencyProfile'); % Apply profile to model

% Create components, ports, and connections
components = addComponent(arch,{'Sensor','Planning','Motion'});
sensorPorts = addPort(components(1).Architecture,{'MotionData','SensorData'},{'in','out'});
planningPorts = addPort(components(2).Architecture,{'SensorData','MotionCommand'},{'in','out'});
motionPorts = addPort(components(3).Architecture,{'MotionCommand','MotionData'},{'in','out'});
c_sensorData = connect(arch,components(1),components(2));
c_motionData = connect(arch,components(3),components(1));
c_motionCommand = connect(arch,components(2),components(3));

% Clean up canvas
Simulink.BlockDiagram.arrangeSystem('archModel'); 

% Batch apply stereotypes to model elements
batchApplyStereotype(arch,'Component','LatencyProfile.NodeLatency');
batchApplyStereotype(arch,'Port','LatencyProfile.PortLatency');
batchApplyStereotype(arch,'Connector','LatencyProfile.ConnectorLatency');

% Instantiate using the analysis function
instance = instantiate(model.Architecture,'LatencyProfile','NewInstance', ...
'Function',@calculateLatency,'Arguments','3','Strict',true, ...
'NormalizeUnits',false,'Direction','PreOrder')

instance = 
  ArchitectureInstance with properties:

        Specification: [1x1 systemcomposer.arch.Architecture]
             IsStrict: 1
       NormalizeUnits: 0
     AnalysisFunction: @calculateLatency
    AnalysisDirection: PreOrder
    AnalysisArguments: '3'
      ImmediateUpdate: 0
           Components: [1x3 systemcomposer.analysis.ComponentInstance]
                Ports: [0x0 systemcomposer.analysis.PortInstance]
           Connectors: [1x3 systemcomposer.analysis.ConnectorInstance]
                 Name: 'NewInstance'

Inspect Component, Port, and Connector Instances

Get properties from component, port, and connector instances.

defaultResources = instance.Components(1).getValue('LatencyProfile.NodeLatency.resources')

defaultResources = 1

defaultSecure = instance.Connectors(1).getValue('LatencyProfile.ConnectorLatency.secure')

defaultSecure = logical
   1

defaultQueueDepth = instance.Components(1).Ports(1).getValue('LatencyProfile.PortLatency.queueDepth')

defaultQueueDepth = 4.2900

Clean Up

Uncomment the following code and run to clean up the artifacts created by this example:

% bdclose('archModel')
% systemcomposer.profile.Profile.closeAll

Battery Sizing and Automotive Electrical System Analysis

Overview

This example shows how to model a typical automotive electrical system as an architectural model and run primitive analysis. The elements in the model can be broadly grouped as either source or load. Various properties of the sources and loads are set as part of the stereotype. The example uses the iterate method of the specification API to iterate through each element of the model and run analysis using the stereotype properties.

Structure of the Model

The generator charges the battery while the engine is running. The battery, along with the generator supports the electrical loads in the vehicle, like ECU, radio, and body control. The inductive loads like motors and other coils have the InRushCurrent stereotype property defined. Based on the properties set on each component, the following analyses are performed:

• Total KeyOffLoad.

• Number of days required for KeyOffLoad to discharge 30% of the battery.

• Total CrankingInRush current.

• Total Cranking current.

• Ability of the battery to start the vehicle at 0°F based on the battery cold cranking amps (CCA). The discharge time is computed based on Puekert coefficient (k), which describes the relationship between the rate of discharge and the available capacity of the battery.

Load the Model and Run the Analysis

archModel = systemcomposer.openModel('scExampleAutomotiveElectricalSystemAnalysis');
% Instantiate battery sizing class used by the analysis function to store
% analysis results.
objcomputeBatterySizing = computeBatterySizing;
% Run the analysis using the iterator.
archModel.iterate('Topdown',@computeLoad,objcomputeBatterySizing);
% Display analysis results.
objcomputeBatterySizing.displayResults;

Total KeyOffLoad: 158.708 mA
Number of days required for KeyOffLoad to discharge 30% of battery: 55.789.
Total CrankingInRush current: 70 A
Total Cranking current: 104 A
CCA of the specifed battery is sufficient to start the car at 0 F.

Close the Model

bdclose('scExampleAutomotiveElectricalSystemAnalysis');

More About

Definitions

Term	Definition	Application	More Information
analysis	Analysis is a method for quantitatively evaluating an architecture for certain characteristics. Static analysis analyzes the structure of the system. Static analysis uses an analysis function and parametric values of properties captured in the system model.	Use analysis to calculate overall reliability, mass roll-up, performance, or thermal characteristics of a system, or to perform a SWaP analysis.	Analyze Architecture
instance	An instance is an occurrence of an architecture model at a given point of time.	You can update an instance with changes to a model, but the instance will not update with changes in active variants or model references. You can use an instance, saved in an .MAT file, of a System Composer™ architecture model for analysis.	Create a Model Instance for Analysis

Term	Definition	Application	More Information
architecture	A System Composer architecture represents a system of components and how they interface with each other structurally and behaviorally. You can represent specific architectures using alternate views.	Different types of architectures describe different aspects of systems: Functional architecture describes the flow of data in a system. Logical architecture describes the intended operation of a system. Physical architecture describes the platform or hardware in a system.	Compose Architecture Visually
model	A System Composer model is the file that contains architectural information, including components, ports, connectors, interfaces, and behaviors.	Perform operations on a model: Extract the root level architecture contained in the model. Apply profiles. Link interface data dictionaries. Generate instances from model architecture. System Composer models are stored as .slx files.	Create an Architecture Model
component	A component is a nontrivial, nearly-independent, and replaceable part of a system that fulfills a clear function in the context of an architecture. A component defines an architecture element, such as a function, a system, hardware, software, or other conceptual entity. A component can also be a subsystem or subfunction.	Represented as a block, a component is a part of an architecture model that can be separated into reusable artifacts.	Components
port	A port is a node on a component or architecture that represents a point of interaction with its environment. A port permits the flow of information to and from other components or systems.	There are different types of ports: Component ports are interaction points on the component to other components. Architecture ports are ports on the boundary of the system, whether the boundary is within a component or the overall architecture model.	Ports
connector	Connectors are lines that provide connections between ports. Connectors describe how information flows between components or architectures.	A connector allows two components to interact without defining the nature of the interaction. Set an interface on a port to define how the components interact.	Connections