State Reader

Read a block state

• Library:

• Simulink / Signal Routing

• 

Description

The State Reader block reads the current state of a supported state owner block.

State Reader blocks can read state from these state owner blocks:

• Discrete State-Space

• Discrete-Time Integrator

• Delay

• Unit Delay

• Discrete Transfer Fcn

• Discrete Filter

• Discrete FIR Filter

• Integrator

• Second-Order Integrator

• Outport of conditional subsystem blocks such as Enabled Subsystem, Triggered Subsystem, and Function-Call Subsystem

• S-Function with multiple discrete states

  To configure an S-Function block as a state owner block, each data type work vector must be declared as a discrete state vector using ssSetDWorkUsedAsDState and named using ssSetDWorkName or ssSetDWorkRTWIdentifier in mdlInitializeSizes.

Tip

You can determine whether a block is a supported state owner block by the value of the block's IsStateOwnerBlock parameter. The expression

get_param(blk,'IsStateOwnerBlock')

where blk is a block name or handle, returns 'on' if the block is a supported state owner block and 'off' otherwise.

To add a State Reader or State Writer block to your model, right-click on a state owner block and drag to an empty portion of the Simulink^® canvas. When you release, a menu will appear. Select Create State Reader Block or Create State Writer Block.

After you create a State Reader or State Writer block, a badge appears above the state owner block, and the name of the state owner block appears next to the State Reader or State Writer block.

A State Reader or State Writer block cannot remain in the same system as its state owner block. After you create a State Reader or State Writer block, cut and paste it to move it to the desired location within the model hierarchy.

Alternatively, you can add a State Reader or State Writer block to your model from the Simulink Library Browser, then set the State owner block parameter from the block parameters dialog.

Note

When you create a library block with a State Reader or State Writer block, you must also include the corresponding state owner block in the library block.

You can select a State Reader or State Writer block or a corresponding state owner block to highlight blocks related to it.

Ports

Output

Out — State value

scalar | vector

State value read from a state owner block.

The dimension of the output is the dimension of the full state vector. Refer to the Initial conditions parameter for specific blocks. For example, for a Delay block with a Delay length of N, the State Reader block returns a state vector of length [1xN].

Data Types: single | double | half | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fixed point

Parameters

State owner block — Show the state owner block

none (default)

Show the state owner block whose state this block is reading. To change the state owner block, select a block from the State Owner Selector Tree.

Programmatic Use

Block Parameter: StateOwnerBlock

Type: character vector

Value: '' | '<model path/block name>'

Default: ''

Model Examples

Working with the Initialize Function, Reset Function, and Terminate Function Blocks

Use the Initialize Function, Reset Function, and Terminate Function blocks to read and write states in a Simulink model.

Open Model

Reading and Writing States with the Initialize Function and Terminate Function Blocks

In this example, the Initialize Function block uses the State Writer block to set the initial condition of a Discrete Integrator block to 10.

Open Model

Block Characteristics

Data Types	Boolean | bus | double | enumerated | fixed point | half | integer | single
Direct Feedthrough	no
Multidimensional Signals	yes
Variable-Size Signals	no
Zero-Crossing Detection	no

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.