Object ‘Persistent variable list’

Symbol:

The object contains the declaration of global persistent variables in the declaration section VAR_GLOBAL PERSISTENT RETAIN .. END_VAR. The variables are stored in special non-volatile memory.

The persistence editor shows the variables as a list in the usual way. The displayed list does not influence the persistence behavior of the variables, but only the list stored internally in the process image. The list there contains all variables ever declared in chronological order. Variables that you have removed are marked with a placeholder and continue to exist as a gap.

The declaration section can also contain instance paths, which refer to locally declared persistent variables and were created with the command Declarations ‣ Add all instance paths .

Hint

Before you decide how to set up persistence for an application, it would be helpful for you to be familiar with the use cases described in the Data Persistence section. Moreover, it is helpful if you can differentiate between the mechanisms of persistent variables, retain variables, variables of the Persistence Manager, and recipe variables.

Commands

The following commands are provided in the persistence editor:

  • Command Declarations ‣ Add all instance paths
  • Command Declarations ‣ Reorder list and clear gaps

See also