Modifiers in Short Class Definitions

1 Simple Short Class Definitions

A few simple examples of short class definitions with modifiers are shown below, all being modifications of the superclass Real:

class Current = Real(unit = "mA");
type Force3 = Real[3](unit = {"N", "N", "N"});
type Voltage = Real(unit = "V", min = -220.0, max = 220.0);

2 LowPassFilter

model LowPassFilter1 constant Real ystart = 1; parameter Real T = 1; parameter Real u = 5; Real y(start = ystart,fixed=true); equation T*der(y) + y = u; end LowPassFilter1;

LowPassFilter20 is a modification of the model LowPassFilter1, with the changed values of ystart and T.

model LowPassFilter20 = LowPassFilter1(ystart = 0, T = 20);

The two models LowPassFilter1 and LowPassFilter20 can be replaced by the single model LowPassFilter20B.

model LowPassFilter20B constant Real ystart = 0; parameter Real T = 20; parameter Real u = 5; Real y(start = ystart,fixed=true); equation T*der(y) + y = u; end LowPassFilter20B;

3 Simulation of LowPassFilter

simulate( LowPassFilter1, stopTime=15 )
plot( y )

simulate( LowPassFilter20, stopTime=20 )

Take a look at some values of y at time=0.0001, time=10, time=20:

{val(y,0.0001), val(y,10.), val(y,20.)}

Simulate the second filter:

simulate( LowPassFilter20B, stopTime=20 )
plot( y )