In Prode Properties one can define a reference temperature and a initial value for enthalpy and entropy. For example I can set as initial temperature 1 K in order to obtain only positive values for enthalpy and entropy; the same, if I set a high positive value as for example 50000 Kj/Kg. This is useful since by changing initial temperature and base value I can match the results from other simulators and tables of values.

However Prode has another option which is the enthalpy (and entropy) of formation in database. I do not know when to use this option and the manual gives little information about. Can you explain ?