Undefined function or variable for struct variable

I have defined 'createModel' function but when I call struct variables from command window , for example

model.pmin(5) or unifrnd(pmin,pmax)

I get this error:

Undefined function or variable 'pmin'.

My code was attached. I have searched some similar questions but I cant solve yet. I really appreciate any help

Thanks in advance

Raha

function model=createModel ()
pmin=[553   782   502   781   608   461   553   699];
pmax=[2078 1907 1864 1562 1982 1437 1626 2138];
N=numel(pmin);
PL=10000;
a0=[7349 7737 6566 8530 9045 7502 6903 9809];
a1=[8 5 5 5 6 9 8 7];
a2=[-0.1817 -0.1010  -0.1395   -0.2037  -0.2740   -0.2296  -0.2540   -0.1358]*1e-4;
model.pmin=pmin;
model.pmax=pmax;
model.N=N;
model.PL=PL;
model.a0=a0;
model.a1=a1;
model.a2=a2;
end

[Stephen23]

It works for me:

S = createModel();
S.pmin(5)

ans = 608

function model=createModel ()
pmin=[553   782   502   781   608   461   553   699];
pmax=[2078 1907 1864 1562 1982 1437 1626 2138];
N=numel(pmin);
PL=10000;
a0=[7349 7737 6566 8530 9045 7502 6903 9809];
a1=[8 5 5 5 6 9 8 7];
a2=[-0.1817 -0.1010  -0.1395   -0.2037  -0.2740   -0.2296  -0.2540   -0.1358]*1e-4;
model.pmin=pmin;
model.pmax=pmax;
model.N=N;
model.PL=PL;
model.a0=a0;
model.a1=a1;
model.a2=a2;
end

[raha ahmadi]

Thank you Stephen Cobeldick, I am really confused!