Compute the open-loop response of the following
control system model at an analysis point specified by an `AnalysisPoint`

block, `X`

.

Create a model of the system by specifying and connecting
a numeric LTI plant model `G`

, a tunable controller `C`

,
and the `AnalysisPoint`

block `X`

.

`T`

is a `genss`

model that
represents the closed-loop response of the control system from *r* to *y*.
The model contains the `AnalysisPoint`

block `X`

that
identifies the potential loop-opening location.

Calculate the open-loop point-to-point loop transfer at
the location `X`

.

This command computes the positive-feedback transfer function
you would obtain by opening the loop at `X`

, injecting
a signal into `G`

, and measuring the resulting response
at the output of `C`

. By default, `getLoopTransfer`

computes
the positive feedback transfer function. In this example, the positive
feedback transfer function is *L*(*s*) = –*G*(*s*)*C*(*s*)

The output `L`

is a `genss`

model
that includes the tunable block `C`

. You can use `getValue`

to
obtain the current value of `L`

, in which all the
tunable blocks of `L`

are evaluated to their current
numeric value.

Compute the negative-feedback open-loop transfer
of the following control system model at an analysis point specified
by an `AnalysisPoint`

block, `X`

.

Create a model of the system by specifying and connecting
a numeric LTI plant model `G`

, a tunable controller `C`

,
and the `AnalysisPoint`

block `X`

.

`T`

is a `genss`

model that
represents the closed-loop response of the control system from *r* to *y*.
The model contains the `AnalysisPoint`

block `X`

that
identifies the potential loop-opening location.

Calculate the open-loop point-to-point loop transfer at
the location `X`

.

This command computes the open-loop transfer function from the
input of `G`

to the output of `C`

,
assuming that the loop is closed with negative feedback. That is,
the relationships between `L`

and `T`

is
given by `T = feedback(L,1)`

. In this example, the
positive feedback transfer function is *L*(*s*) = *G*(*s*)*C*(*s*)

Compute the open-loop response of the inner
loop of the following cascaded control system, with the outer loop
open.

Create a model of the system by specifying and connecting
the numeric plant models `G1`

and `G2`

,
the tunable controllers `C1`

, and the `AnalysisPoint`

blocks `X1`

and `X2`

that
mark potential loop-opening locations.

Compute the negative-feedback open-loop response of the
inner loop, at the location `X2`

, with the outer
loop opened at `X1`

.

By default, the loop is closed at the analysis-point location
marked by the `AnalysisPoint`

block `X1`

.
Specifying `'X1'`

for the `openings`

argument
causes `getLoopTransfer`

to open the loop at `X1`

for
the purposes of computing the requested loop transfer at `X2`

.
In this example, the negative-feedback open-loop response *L*(*s*) = *G*_{2}(*s*)*C*_{2}(*s*).