Persistence in AspenPlus

All versions of AspenPlus prior to V9 will persist a single CAPE-OPEN unit operation properly, but will not properly persist any CAPE-OPEN unit operation if more than one CAPE-OPEN unit operation is present in the flowsheet. To work around this, when running in AspenPlus, the CAPE-OPEN unit operation will save a copy of its spread sheet in the current folder, which is assumed to be the folder containing the simulation, under the same name as the unit operation, with the file extension .xlsx.

Upon reloading an AspenPlus file, if the unit operation is not properly restored via CAPE-OPEN persistence, an xlsx file with the name of the unit is used to restore the unit, if it exists in the current folder.

This work-around has the following caveats:

the current directory should be the directory with the simulation file in it. If it is not, existing xls file of which the file name matches the unit operation name, may be overwritten. If AspenPlus is opened by double clicking the simulation file in Windows Explorer, normally the working directory matches the simulation directory. Care must be taken not to change the directory, e.g. by Save As.
the xls files will overwrite other xls files with unit operations with the same names in the same folder. To prevent this, refrain from saving two simulations in the same folder.
the unit operation name should not contain characters that are illegal in a file name.
the unit operation's private storage is updated each time the unit operation is edited; even if the AspenPlus file is not saved the unit operation configuration will therefore still be overwritten.
input parameter values may not be properly restored. To force the unit operation to save its configuration data, edit the unit operation.
when moving the simulation file to a different folder or computer, the xls files of the unit operations have to be transferred with the simulation file.
the simulation must be stored as .bkp file, not as .apw file