systemcomposer.analysis.Instance

Element in analysis instance

Since R2019a

Description

An Instance object represents an instance of a System Composer™ model element.

Related objects include:

• systemcomposer.analysis.ArchitectureInstance

• systemcomposer.analysis.ComponentInstance

• systemcomposer.analysis.PortInstance

• systemcomposer.analysis.ConnectorInstance

Creation

Create an instance of an architecture using the instantiate function.

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

Analyze Latency Characteristics

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

Create 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("LatencyProfileC");

Add a base stereotype with properties.

latencybase = profile.addStereotype("LatencyBase");
latencybase.addProperty("latency",Type="double");
latencybase.addProperty("dataRate",Type="double",DefaultValue="10");

Add a connector stereotype with properties.

connLatency = profile.addStereotype("ConnectorLatency",...
    Parent="LatencyProfileC.LatencyBase");
connLatency.addProperty("secure",Type="boolean",DefaultValue="true");
connLatency.addProperty("linkDistance",Type="double");

Add a component stereotype with properties.

nodeLatency = profile.addStereotype("NodeLatency",...
    Parent="LatencyProfileC.LatencyBase");
nodeLatency.addProperty("resources",Type="double",DefaultValue="1");

Add a port stereotype with properties.

portLatency = profile.addStereotype("PortLatency",...
    Parent="LatencyProfileC.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);
arch = model.Architecture;

Apply profile to model.

model.applyProfile("LatencyProfileC");

Create components, ports, and connections.

componentSensor = addComponent(arch,"Sensor");
sensorPorts = addPort(componentSensor.Architecture,{'MotionData','SensorPower'},{'in','out'});

componentPlanning = addComponent(arch,"Planning");
planningPorts = addPort(componentPlanning.Architecture,{'Command','SensorPower','MotionCommand'},{'in','in','out'});
componentMotion = addComponent(arch,"Motion");
motionPorts = addPort(componentMotion.Architecture,{'MotionCommand','MotionData'},{'in','out'});

c_sensorData = connect(arch,componentSensor,componentPlanning);
c_motionData = connect(arch,componentMotion,componentSensor);
c_motionCommand = connect(arch,componentPlanning,componentMotion);

Clean up the canvas.

Simulink.BlockDiagram.arrangeSystem("archModel"); 

Batch apply stereotypes to model elements.

batchApplyStereotype(arch,"Component","LatencyProfileC.NodeLatency");
batchApplyStereotype(arch,"Port","LatencyProfileC.PortLatency");
batchApplyStereotype(arch,"Connector","LatencyProfileC.ConnectorLatency");

Instantiate using the analysis function.

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

instance = 
  ArchitectureInstance with properties:

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

Inspect Component, Port, and Connector Instances

Get properties from component, port, and connector instances.

defaultResources = instance.Components(1).getValue("LatencyProfileC.NodeLatency.resources")

defaultResources = 1

defaultSecure = instance.Connectors(1).getValue("LatencyProfileC.ConnectorLatency.secure")

defaultSecure = logical
   1

defaultQueueDepth = instance.Components(1).Ports(1).getValue("LatencyProfileC.PortLatency.queueDepth")

defaultQueueDepth = 4.2900

Battery Sizing and Automotive Electrical System Analysis

Overview

Model a typical automotive electrical system as an architectural model and run a primitive analysis. The elements in the model can be broadly grouped as either a source or a load. Various properties of the sources and loads are set as part of the stereotype. This 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 Model

The generator charges the battery while the engine is running. The battery and the generator support 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 Model and Run Analysis

scExampleAutomotiveElectricalSystemAnalysis
archModel = systemcomposer.loadModel('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 specified battery is sufficient to start the car at 0 F.

ans = 
  computeBatterySizing with properties:

    totalCrankingInrushCurrent: 70
          totalCrankingCurrent: 104
        totalAccesoriesCurrent: 71.6667
               totalKeyOffLoad: 158.7080
                    batteryCCA: 500
               batteryCapacity: 850
            puekertcoefficient: 1.2000

Close 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 analyses to calculate overall reliability, mass roll-up, performance, or thermal characteristics of a system, or to perform a SWaP analysis.	Analyze Architecture Model with Analysis Function Analyze Architecture Simple Roll-Up Analysis Using Robot System with Properties
analysis function	An analysis function is a MATLAB® function that computes values necessary to evaluate the architecture using the properties of each element in the model instance.	Use an analysis function to calculate the result of an analysis.	Analysis Function Constructs Write Analysis Function
instance model	An instance model is a collection of instances.	You can update an instance model with changes to a model, but the instance model will not update with changes in active variants or model references. You can use an instance model, saved in a MAT file, of a System Composer architecture model for analysis.	Run Analysis Function
instance	An instance is an occurrence of an architecture model element at a given point in time.	An instance freezes the active variant or model reference of the component in the instance model.	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.	Different types of architectures describe different aspects of systems. You can use views to visualize a subset of components in an architecture. You can define parameters on the architecture level using the Parameter Editor.	Compose Architectures Visually Author Parameters in System Composer Using Parameter Editor
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. A System Composer model is stored as an SLX file.	Create Architecture Model with Interfaces and Requirement Links
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 architectural 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. Transfer information between components with: Port interfaces using the Interface Editor Parameters using the Parameter Editor	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

Version History

Introduced in R2019a