Why do I need more than one link?

Reason 1:

Your controller is able to call multiple instances of the SQL4automation function block. This allows parallel database queries. One instance is for example writing error messages spontaneously using link1 and the other instance is reading the current production data using link 2. Thus you do not need to programme software-based synchronisation.

Reason 2:

If you use multiple controllers in your facility you can allocate one or more links to each controller.