getBlockValue

Get current value of tuned block parameterization in slTuner interface

Syntax

value = getBlockValue(st,blk)

[val1,val2,...] = getBlockValue(st,blk1,blk2,...)

S = getBlockValue(st)

Description

getBlockValue lets you access the current value of the parameterization of a tuned block in an slTuner interface.

An slTuner interface parameterizes each tuned Simulink^® block as a Control Design Block, or a generalized parametric model of type genmat or genss. This parameterization specifies the tuned variables for commands such as systune.

value = getBlockValue(st,blk) returns the current value of the parameterization of a tunable block, blk, in an slTuner interface.

[val1,val2,...] = getBlockValue(st,blk1,blk2,...) returns the current values of the parameterizations of one or more tuned blocks of st.

S = getBlockValue(st) returns a structure containing the current values of the parameterizations of all tuned blocks of st.

Examples

Get Current Value of Tuned Block Parameterization

Create an slTuner interface for the scdcascade model.

open_system('scdcascade')
st = slTuner('scdcascade',{'C1','C2'});

Examine the current parameterization value of one of the tuned blocks.

val = getBlockValue(st,'C1')

val =
 
             1 
  Kp + Ki * ---
             s 

  with Kp = 0.158, Ki = 0.042
 
Name: C1
Continuous-time PI controller in parallel form.

Get Current Values of Multiple Tuned Block Parameterizations

Create an slTuner interface for the scdhelicopter model.

open_system('scdhelicopter')
st = slTuner('scdhelicopter',{'PI1','PI2','PI3','SOF'});

Retrieve the values of parameterizations for the PI controller blocks in the model.

[valPI1,valPI2,valPI3] = getBlockParam(st,'PI1','PI2','PI3');

Get Current Values of All Tuned Block Parameterizations

Create an slTuner interface for the scdcascade model.

open_system('scdcascade')
st = slTuner('scdcascade',{'C1','C2'});

Retrieve the parameterization values for both tuned blocks in st.

blockValues = getBlockValue(st)

blockValues = 

  struct with fields:

    C1: [1×1 pid]
    C2: [1×1 pid]

blockValues is a structure with field names corresponding to the names of the tunable blocks in st. The field values of blockValues are pid models, because C1 and C2 are both PID Controller blocks.

Input Arguments

st — Interface for tuning control systems modeled in Simulink

slTuner interface

Interface for tuning control systems modeled in Simulink, specified as an slTuner interface.

blk — Block

character vector | string

Block in the list of tuned blocks for st, specified as a character vector or string. You can specify the full block path or any portion of the block path that uniquely identifies the block among the other tuned blocks of st.

Example: blk = 'scdcascade/C1', blk = "C1"

Output Arguments

value — Current value of block parameterization

numeric LTI model

Current value of block parameterization, returned as a numeric LTI model, such as pid, ss, or tf.

When the tuning results have not been applied to the Simulink model using writeBlockValue, the value returned by getBlockValue can differ from the actual Simulink block value.

Note

Use writeBlockValue to align the block parameterization values with the actual block values in the Simulink model.

S — Current values of all block parameterizations

structure

Current values of all block parameterizations in st, returned as a structure. The names of the fields in S are the names of the tuned blocks in st, and the field values are the corresponding numeric LTI models.

You can use this structure to transfer the tuned values from one slTuner interface to another slTuner interface with the same tuned block parameterizations.

S = getBlockValue(st1);
setBlockValue(st2,S);

More About

Tuned Blocks

Tuned blocks, used by the slTuner interface, identify blocks in a Simulink model whose parameters are to be tuned to satisfy tuning goals. You can tune most Simulink blocks that represent linear elements such as gains, transfer functions, or state-space models. (For the complete list of blocks that support tuning, see How Tuned Simulink Blocks Are Parameterized). You can also tune more complex blocks such as SubSystem or S-Function blocks by specifying an equivalent tunable linear model.

Use tuning commands such as systune to tune the parameters of tuned blocks.

You must specify tuned blocks (for example, C1 and C2) when you create an slTuner interface.

st = slTuner('scdcascade',{'C1','C2'})

You can modify the list of tuned blocks using addBlock and removeBlock.

To interact with the tuned blocks use:

• getBlockParam, getBlockValue, and getTunedValue to access the tuned block parameterizations and their current values.

• setBlockParam, setBlockValue, and setTunedValue to modify the tuned block parameterizations and their values.

• writeBlockValue to update the blocks in a Simulink model with the current values of the tuned block parameterizations.

Tuned Variables

Within an slTuner interface, tuned variables are any Control Design Blocks involved in the parameterization of a tuned Simulink block, either directly or through a generalized parametric model. Tuned variables are the parameters manipulated by tuning commands such as systune.

For Simulink blocks parameterized by a generalized model or a tunable surface:

• getBlockValue provides access to the overall value of the block parameterization. To access the values of the tuned variables within the block parameterization, use getTunedValue.

• setBlockValue cannot be used to modify the block value. To modify the values of tuned variables within the block parameterization, use setTunedValue.

For Simulink blocks parameterized by a Control Design Block, the block itself is the tuned variable. To modify the block value, you can use either setBlockValue or setTunedValue. Similarly, you can retrieve the block value using either getBlockValue or getTunedValue.

Version History

Introduced in R2011b