In PIPING_PORT table, the PD_GEN_ID column can receive the values 0 and 1.
When importing a few lines into the PIPING_PORT table, only one line can have PD_GEN_ID = 1, and this line will be used in the relevant instrument’s process data sheet, in the "Associated line" field.
All the other lines imported into PIPING_PORT should have PD_GEN_ID = 0.
When using a link to update PIPING_PORT, PD_GEN_ID = 0 means that the associated line will be removed from the process data sheet.