Simulink.BusElement

Specify properties of elements of buses

Description

A Simulink.BusElement object specifies the properties of a signal in a bus.

BusElement objects validate the properties of signals in a bus. A Simulink.Bus object contains BusElement objects. A BusElement object exists only within a Bus object. You can specify a bus object, but not a BusElement object, as a block parameter value. When you simulate a model or update diagram, Simulink^® checks whether the signals in a bus connected to blocks have the properties specified by the BusElement objects. If not, Simulink halts and displays an error message.

You can use the Simulink Bus Editor (see Create and Specify Bus Objects), or MATLAB^® commands (see Create Bus Objects Programmatically) to create and modify Bus objects and BusElement objects in the base MATLAB workspace.

Creation

Syntax

busElementObject = Simulink.BusElement

Description

busElementObject = Simulink.BusElement returns a BusElement object with these property values:

              Name: 'a'
        Complexity: 'real'
        Dimensions: 1
          DataType: 'double'
               Min: []
               Max: []
    DimensionsMode: 'Fixed'
        SampleTime: -1
              Unit: ''
       Description: ''

Properties

Name — Name of element

character vector

Name of element, specified as a character vector.

Complexity — Numeric type of element

'real' (default) | 'complex'

Numeric type of the element, specified as 'real' or 'complex'.

Dimensions — Dimensions of element

array

Dimensions of element, specified as an array.

DataType — Data type of element

built-in Simulink data type | a Simulink.NumericType object | a Simulink.Bus object

Data type of element, specified as a built-in Simulink data type or Simulink.NumericType object. Examples of built-in data types include double and uint8. You can specify a Simulink.NumericType object whose DataTypeMode property is set to a value other than 'Fixed-point: unspecified scaling'. Specifying a Bus object allows you to create Bus objects that specify hierarchical buses (that is, buses that contain other buses).

Min — Minimum value of element

double | []

Minimum value of the element, specified as a double. This value must be a finite real double scalar or, if the element is a bus, the value must be empty, [].

Max — Maximum value of element

double | []

Maximum value of the element, specified as a double. This value must be a finite real double scalar or, if the element is a bus, the value must be empty, [].

DimensionsMode — Specify how to handle size of element

'Fixed' (default) | 'Variable'

Specify how to handle size of element, specified as 'Fixed' or 'Variable'.

SampleTime — Sample time of element

-1 (default) | double

Sample time of element, specified as a double. The sample time is the size of the interval between times when this signal value must be recomputed. If these conditions apply, use the default value of -1:

• The element is a bus.

• The bus that includes this element passes through a block that changes the bus sample time, such as a Rate Transition block.

Unit — Physical unit for expressing element

character vector

Physical unit for expressing element, specified as a character vector (for example, 'inches').

Examples

Create Bus Objects and BusElement Objects

This example shows how to create a Bus object and its associated BusElement objects in the base workspace.

Create a Bus object named CONTROL.

CONTROL = Simulink.Bus;

Create and specify properties for two BusElement objects, named VALVE1 and VALVE2.

valve1 = Simulink.BusElement;
valve1.Name = 'VALVE1';
valve1.Dimensions = 1;
valve1.DimensionsMode = 'Fixed';
valve1.DataType = 'double';
valve1.SampleTime = -1;
valve1.Complexity = 'real';

valve2 = Simulink.BusElement;
valve2.Name = 'VALVE2';
valve2.Dimensions = 1;
valve2.DimensionsMode = 'Fixed';
valve2.DataType = 'double';
valve2.SampleTime = -1;
valve2.Complexity = 'real';

Assign the elements to the CONTROL Bus object.

CONTROL.Elements = [valve1 valve2];

Alternatives

To interactively create a BusElement object, use the Bus Editor.

To create BusElement objects from blocks in a model, MATLAB data, and external C code, see Create Bus Objects Programmatically.

Compatibility Considerations

Simulink.BusElement objects will no longer support the SampleTime property

Not recommended starting in R2019b

In a future release, the SampleTime property of Simulink.BusElement objects will be removed.

To prepare:

• When defining BusElement objects, use the default SampleTime value (-1).

• To specify the sample time for an element of a bus, use the SampleTime block parameter of corresponding blocks. For example, you can use In Bus Element, Out Bus Element, and Signal Specification blocks to specify sample time.

Simulink.BusElement objects will no longer support the SamplingMode property

Not recommended starting in R2016b

In R2016b, the SamplingMode property of Simulink.BusElement objects was removed. Scripts that use the SamplingMode property of Simulink.BusElement objects continue to work. Simulink.Bus.cellToObject continues to require the SamplingMode field and Simulink.Bus.objectToCell continues to include the sampling mode in the output cell arrays.

In a future release, support for the SamplingMode property will be removed.

To specify whether a signal is sample-based or frame-based, define the sampling mode of input signals at the block level instead of at the signal level.