function structure = ES_eqn(name,bond_number,bonds,direction,cr,args, ...
structure,eqnfile);
% ES_eqn - equations for ES component
%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %%%%% Model Transformation Tools %%%%%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Matlab function ES_eqn
% ES_eqn(name,bond_number,bonds,direction,cr,args, ...
% structure,eqnfile);
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% Version control history
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %% $Id$
% %% $Log$
% %% Revision 1.2 1998/02/25 16:59:56 peterg
% %% Corrected enthalpy-entropy conversion -- use temp on the entropy side.
% %%
% %% Revision 1.1 1998/02/25 15:03:51 peterg
% %% Initial revision
% %%
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Copyright (c) P.J. Gawthrop, 1997.
if nargin<6
eqnfile = 'stdout';
end;
% Check that there are exactly two bonds.
ports = 2;
if check_bonds(bonds,ports,'ES')==0
return
end
% There are 2 ports; extract the information
e_bond = bonds(1,:);
s_bond = bonds(2,:);
% The efforts are the same - but the enthalpy side has relative T
if e_bond(1)==1 %effort imposed on the enthalpy bond
% fprintf(eqnfile,'%s := %s + t_0;\n' , ...
fprintf(eqnfile,'%s := %s;\n' , ...
varname(name,bond_number(2), 1), ...
varname(name,bond_number(1), 1) );
else %effort imposed on the entropy bond
% fprintf(eqnfile,'%s := %s - t_0;\n' , ...
fprintf(eqnfile,'%s := %s;\n' , ...
varname(name,bond_number(1), 1), ...
varname(name,bond_number(2), 1) );
end;
% The flows need to be converted - use the absolute temp on the
% entropy side
if e_bond(2)==-1 %flow imposed on the enthalpy bond
fprintf(eqnfile,'%s := %s/%s;\n' , ...
varname(name,bond_number(2), -1), ...
varname(name,bond_number(1), -1), ...
varname(name,bond_number(2), 1) );
else % flow imposed on the entropy bond
fprintf(eqnfile,'%s := %s*%s;\n' , ...
varname(name,bond_number(1), -1), ...
varname(name,bond_number(2), -1), ...
varname(name,bond_number(2), 1) );
end;