FAQ Group: Programming issues

8.2 ChemApp does not read a data-file properly, how do I find out what is wrong?

If an error occurs (error no. 103 or 102) while reading the thermodynamic data-file using TQRFIL (Read – File), the reason is typically one of the following: The file has not been opened properly.  This can especially happen when the subroutine TQOPEN (Open – File) is used (i.e. when programming in languages other than FORTRAN) …

8.2 ChemApp does not read a data-file properly, how do I find out what is wrong? Read More »

8.3 ChemApp says it cannot calculate an equilibrium, what is wrong?

If ChemApp indicates that it cannot calculate an equilibrium, typically returning error numbers 701 or 702 after a call to TQCE (Calculate – Equilibrium) or TQCEL (Calculate – Equilibrium – List – Results), check the conditions which are active for the equilibrium calculation in question using TQSHOW (Show – Present – Settings). Then check the …

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8.4 I want to retrieve Cp/H/S/G for a phase constituent, do I use TQGETR or TQGDPC?

Both TQGETR (Get – Results) and TQGDPC (Get – Thermodynamic – Data – Phase – Constituent) allow you to retrieve the values for these thermodynamic functions for phase constituents. The difference is that TQGETR retrieves these values for the previously calculated equilibrium state. The values retrieved with TQGDPC, on the other hand, have nothing to do …

8.4 I want to retrieve Cp/H/S/G for a phase constituent, do I use TQGETR or TQGDPC? Read More »

8.5 I’m performing a calculation at constant volume and it fails, what can I do about it?

The answer in short: Perform a target calculation with volume as target and pressure as target variable instead. When calculations are made under constant product volume by using the option ‘VT’ of the subroutines TQSETC (Set – Equilibrium – Condition) or TQSTEC (Set – Equilibrium – Condition – When – Stream – Input), ChemApp will …

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8.6 Why do the results I retrieve with TQSTXP look wrong or are all zero?

For users of ChemApp versions prior to 3.2.0: The values returned by TQSTXP (Get – Thermodynamic – Property – Of – A – Stream) always refer to the last calculated equilibrium state. If TQSTXP is called before the first equilibrium calculation has been performed using TQCE (Calculate – Equilibrium) or TQMAP (Calculate – One – …

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