fotf error in step command

i tray to design toff control for magnetic levitation sys

i have problem when i use the following command

sys=fotf([2012.4087 107.2882 1.0305],[1.8063 0.93529 0],[1],[0]);
 opt = stepDataOptions('InputOffset',-1.5,'StepAmplitude',-2);
    figure(2)
 figure(2)
 step(sys,opt);

or

step(sys,100)

i get

Index exceeds the number of array elements (1).

Error in fotf/lsim (line 38)

h=t(2)-t(1);

Error in fotf/step (line 16)

y=lsim(G,u,t);

Error in test (line 4)

step(sys,opt);

Pleas your kind help and advice

[Walter Roberson]

Is it https://www.mathworks.com/matlabcentral/fileexchange/60874-fotf-toolbox that you are using?

[Stephen23]

salwan yousif's "Answer" moved here:

when i used this version 1.3 (2.31 MB) by Dingyu Xue i get the following error

Undefined operator '/' for input arguments of type 'ltioptions.step'.

Error in fotf/step (line 12)

if nargin==1, t=[0:0.2:10]'; elseif length(t)==1, t=0:t/100:t; end

Error in test (line 5)

step(sys,opt);

Answer 1

[Walter Roberson]

I see no evidence that stepDataOptions is supported for fotf()

fotf() is not tf(), and is not an extension of tf() . It is a separate third-party package.

The second input to step() for fotf() must be a time vector or else a scalar giving the frequency.