function sys = pidstd(varargin) %#ok<STOUT>
%PIDSTD  Error out when realp, ureal or genmat is part of PID parameters.

%   Copyright 2009-2012 The MathWorks, Inc.

% When the first non-primitive input argument is a @StaticModel object,
% this method is called and we error out immediately because:
% (1) an uncertain PID controller has so far no practical use (ureal)
% (2) we have @ltiblock.pid for tunable PID controller (realp, genmat)
for ct=1:nargin
    para = varargin{ct};
    if isa(para,'StaticModel')
        if isUncertain(para)
            error(message('Control:ltiobject:pidNoURealInput'))
        else
            error(message('Control:ltiobject:pidNoGenmatInput'))
        end
    end
end