getlinio - Linearization input/output (I/O) settings for Simulink model, Linear Analysis Plots or Model Verification block

Syntax

io = getlinio('sys')
io = getlinio('blockpath')

Alternatives

As an alternative to the getlinio function, view linearization I/Os in the:

• Analysis I/Os pane of the Linearization Task node in the Control and Estimation Tools Manager GUI for Simulink models.

• Linearization inputs/outputs table in the Linearizations tab of the Block Parameters dialog box for Linear Analysis Plots or Model Verification blocks.

Description

io = getlinio('sys') finds all linearization inputs/outputs (I/Os) in the Simulink model, sys, and returns a vector of objects, io. Each object represents a linearization annotation in the model and is associated with an output port of a Simulink block. Before running getlinio, use the right-click menu to insert the linearization annotations, or I/Os, on the signal lines of the model diagram.

io = getlinio('blockpath') finds all I/Os in a Linear Analysis Plots or Model Verification block. blockpath is the full path to the block. io is a vector of objects and has an entry for each linearization port used by the block.

Each object within the vector, io, has the following properties:

Active	Set this value to 'on', when the I/O is used for linearization, and 'off' otherwise
Block	Name of the block with which the I/O is associated
OpenLoop	Set this value to 'on', when the feedback loop at the I/O is open, and 'off', when it is closed
PortNumber	Integer referring to the output port with which the I/O is associated
Type	Choose one of the following linearization I/O types: 'in': linearization input point 'out': linearization output point 'outin': linearization output then input point 'inout': linearization input then output point
BusElement	Bus element name with which the I/O is associated. Empty string ('') if the I/O is not a bus element.
Description	String description of the I/O object

You can edit this I/O object to change its properties. Alternatively, you can change the properties of io using the set function. To upload an edited I/O object to the Simulink model diagram, use the setlinio function. Use I/O objects with the function linearize to create linear models.

Examples

Find linearization inputs/outputs in a Simulink model.

Before creating a vector of I/O objects using getlinio, you must add linearization annotations representing the I/Os, such as input points or output points, to a Simulink model.

1. Open a Simulink model.

   magball
   

2. Right-click the signal line between the Magnetic Ball Plant and the Controller. Select Linearization Points > Input Point from the menu to place an input point on this signal line.

   A small arrow pointing toward a small circle just above the signal line represents the input point.

3. Right-click the signal line after the Magnetic Ball Plant. Select Linearization Points > Output Point from the menu to place an output point on this signal line.

   A small arrow pointing away from a small circle just above the signal line represents the output point.

4. Create a vector of I/O objects for this model.

   io=getlinio('magball')
   

   This syntax returns a formatted display of the linearization I/Os.

   2x1 vector of Linearization IOs: 
   --------------------------
   1. Linearization input located at the following signal:
   - Block: magball/Controller
   - Port: 1
   
   2. Linearization output with a loop opening located at the following signal:
   - Block: magball/Magnetic Ball Plant
   - Port: 1

   io is a vector with two entries representing the two linearization annotations previously set in the model diagram. MATLAB also displays:

   • The linearization I/O type (input or output)

   • Whether the IO is a loop opening

   • Block name associated with the I/O

   • Port number associated with the I/O

   By default, the I/Os have no loop openings. Display the properties of each I/O object in more detail using the get function.

This example shows how to find linearization inputs/outputs in a Linear Analysis Plots block to update the I/Os.

1. Open the watertank model, and specify input and output (I/O).

   1. Right-click the Desired Water Level output signal, and select Linearization Points > Input Point.

   2. Right-click the Water-Tank System output signal, and select Linearization Points > Output Point.

   The linearization I/O markers appear in the model, as shown in the next figure.

   

   Alternatively, you can use linio.

2. Drag and drop a Bode Plot block from the Simulink Control Design Linear Analysis Plots library into the model window.

3. Find all I/Os used by the Bode Plot block.

   io = getlinio('watertank/Bode Plot')

   When you drag and drop the block, the block I/Os are set to the model I/Os. The following results appear at the MATLAB prompt:

    2x1 vector of Linearization IOs: 
   --------------------------
   1. Linearization input located at the following signal:
   - Block: watertank/Desired  Water Level
   - Port: 1
   
   2. Linearization output located at the following signal:
   - Block: watertank/Water-Tank System
   - Port: 1

4. Open the loop specified by the block I/Os.

   io(2).OpenLoop = 'on';

   Note   The loop opening does not affect the model I/Os.

5. Update the I/O in the Bode Plot block.

   oldio = setlinio('watertank/Bode Plot',io)

See Also

get | linearize | linio | set | setlinio

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