2-DOF PID controller, returned as a `pid2`

object
or `pidstd2`

object. `C2`

is
in parallel form if `C1`

is in parallel form, and
standard form if `C1`

is in standard form.

For example, suppose `C1`

is a continuous-time,
parallel-form `pid`

controller of the form:

Then `C2`

is a parallel-form 2-DOF `pid2`

controller,
which has two inputs and one output. The relationship between the
inputs, *r* and *y*, and the output *u* of `C2`

is
given by:

The PID gains *K*_{p}, *K*_{i},
and *K*_{d}, and the filter time
constant *T*_{f} are unchanged.
The setpoint weights *b* and *c* are
specified by the input arguments `b`

and `c`

,
or 1 by default. For more information about 2-DOF PID controllers,
see Two-Degree-of-Freedom PID Controllers.

The conversion also preserves the values of the properties `Ts`

, `TimeUnit`

, ```
Sampling
Grid
```

, `IFormula`

, and `DFormula`

.