Using Simulink

Displaying a Transfer Function on the Block Icon

To display a transfer function equation in the block icon, enter the following command in the Drawing commands field.

dpoly(num, den)
dpoly(num, den, 'character')

num and den are vectors of transfer function numerator and denominator coefficients, typically defined using initialization commands. The equation is expressed in terms of the specified character. The default is s. When the icon is drawn, the initialization commands are executed and the resulting equation is drawn on the icon:

• To display a continuous transfer function in descending powers of s, enter

dpoly(num, den)

For example, for num = [0 0 1]; and den = [1 2 1]; the icon looks like this.

• To display a discrete transfer function in descending powers of z, enter

dpoly(num, den, 'z')

For example, for num = [0 0 1]; and den = [1 2 1]; the icon looks like this.

• To display a discrete transfer function in ascending powers of 1/z, enter

dpoly(num, den, 'z-')

For example, for num and den as defined above, the icon looks like this.

• To display a zero-pole gain transfer function, enter

droots(z, p, k)

For example, the above command creates this icon for these values.

z = []; p = [-1 -1]; k = 1;

You can add a fourth argument ('z' or 'z-') to express the equation in terms of z or 1/z.

If the parameters are not defined or have no values when you create the icon, Simulink displays three question marks (? ? ?) in the icon. When the parameter values are entered in the mask dialog box, Simulink evaluates the transfer function and displays the resulting equation in the icon.

Displaying Images on Masks

Controlling Icon Properties