Control System Toolbox Function Reference

get

Access/query LTI property values

Syntax

Value = get(sys,'PropertyName')
get(sys)
Struct = get(sys)

Description

Value = get(sys,'PropertyName') returns the current value of the property PropertyName of the LTI model sys. The string 'PropertyName' can be the full property name (for example, 'UserData') or any unambiguous case-insensitive abbreviation (for example, 'user'). You can specify any generic LTI property, or any property specific to the model sys (see "LTI Properties" for details on generic and model-specific LTI properties).

Struct = get(sys) converts the TF, SS, or ZPK object sys into a standard MATLAB structure with the property names as field names and the property values as field values.

Without left-hand argument,

get(sys)

displays all properties of sys and their values.

Example

Consider the discrete-time SISO transfer function defined by

h = tf(1,[1 2],0.1,'inputname','voltage','user','hello')

You can display all LTI properties of h with

get(h)
        num = {[0 1]}
        den = {[1 2]}
        Variable = 'z'
        Ts = 0.1
        InputDelay = 0
        OutputDelay = 0
        ioDelay = 0
        InputName = {'voltage'}
        OutputName = {''}
        InputGroup = {0x2 cell}
        OutputGroup = {0x2 cell}
        Notes = {}
        UserData = 'hello'

or query only about the numerator and sample time values by

get(h,'num')

ans = 
    [1x2 double]

and

get(h,'ts')

ans =
    0.1000

Because the numerator data (num property) is always stored as a cell array, the first command evaluates to a cell array containing the row vector [0 1].

Remark

An alternative to the syntax

Value = get(sys,'PropertyName')

is the structure-like referencing

Value = sys.PropertyName

For example,

sys.Ts
sys.a
sys.user

return the values of the sample time, matrix, and UserData property of the (state-space) model sys.

See Also
frdata      Quick access to frequency response data

set         Set/modify LTI properties

ssdata      Quick access to state-space data

tfdata      Quick access to transfer function data

zpkdata     Quick access to zero-pole-gain data

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