Experimental Data Files (*.POP, *.DOP)

There is also another type of experimental data file (*.EXP) generated when working with DATAPLOT. See About the DATAPLOT Graphical Language.

If you are using Graphical Mode, the Experimental File Reader activity node is used to plot experimental data on one or more plots.

See the Tips and Tricks: How to Plot Experimental Data blog post on our website for useful guidance about this topic.

In order to conduct an assessment for a system, the experimental data is described with a syntax, which is similar to the way that one calculates an equilibrium in the POLY module or you edit an experimental point in the ED_EXP module. Similar to a Thermo‑Calc macro file (*.TCM), an experimental data file (i.e. the *.POP or *.DOP file) is a basic text file and can be opened and edited by any text editor. For this reason, a *.POP or *.DOP file is not hardware dependent.

A POP or DOP file consists of various commands from the POLY and ED_EXP modules, as well some special commands which can only be used in such experimental data files. Various experimental information can be inputted in an *.POP or *.DOP file as different tables; the same type of experimental data are usually documented in the same table (see below).

A *.POP or *.DOP file is used in the PARROT module to provide experimental information for the optimization process, and is checked by a syntax checker when the PARROT command COMPILE_EXPERIMENTS is proceeded.

The special commenting identifier, i.e. a dollar sign $ which starts a line, is used to document comment lines at any position in a *.POP or *.DOP file. You may remember that this feature is universally the same as in almost all kinds of text files in Thermo‑Calc software, e.g. in *.TDB, *.DAT, *.TCM, *.POP/*.DOP and *.EXP files. Such a sign and all information afterwards in the same comment line is skipped and ignored by the syntax checker.

Many POLY and ED_EXP commands can be directly used in a POP or DOP file. But there are some differences with the set of POLY or ED_EXP commands, and some specially designed commands as described in this topic can only be used in the *.POP or *.DOP files.

Most of the commands in the experimental data file are the same as in the POLY module. The most frequently used are listed below:

The last command in an *.POP or *.DOP file must always be the SAVE command.

Other legal commands from the POLY module that are used less often are:

The DEFINE-COMPONENTS command must be always used as the first command in an *.POP or *.DOP file, as it automatically reinitiates the whole workspace.

Most of the special commands for the ED_EXP module are also often used in an *.POP or *.DOP file. For example:

The following special ED_EXP commands are illegal and should not be used in any *.POP or *.DOP file:

  • COMPUTE-ALL-EQUILIBRIA
  • MAKE-POP-FILE
  • READ (READ-BLOCK OR READ-WORKSPACE)
  • TRANSFER-START-VALUES