function G = MGain_2est_xyScal(Delta,t1,t2)
global Col nominal

% str = HyCase.Flowsheet.MaterialStreams.Item('F'); %pointer to stream named 2
% F = str.MolarFlowValue;


T = Col.ColumnFlowsheet.TemperaturesValue; 
BB(1:length(T)) = T;
Y = BB;

Y0 = nominal(23:end);
Y0scal = log((Y0-t1)./(t2-Y0));
Yscal = log((Y-t1)./(t2-Y));
%G = abs(BB - nominal(23:end)) / (Delta);
G = (Yscal - Y0scal) / (Delta);