This interaction is used to make sure that any shipments that have occurred in Brightpearl have been sent to Magento. If this interaction is turned on and you have your cron setup correctly then Magento will look back over the specified time period to ensure that all shipments that have been created or updated in Brightpearl have been imported into Magento.
So if, for whatever reason, communication is lost between your server or Brightpearl then this interaction can be run to make sure anything missed is retried.
The cron schedule specifies how often it runs and if you couple this with a suitable lookbehind you should ensure that no shipments are missed.
The Lookbehind specifies how far in past it checks.
The Batch size specifies how many shipments it should try and retrieve in each batch
The Sleep time specifies how long it should wait between each batch
You can choose to have this interaction run using your cron schedules but you can also run it manually whenever you wish (maybe after performing maintenance / security updates on your server for example). This interaction, in conjunction with the Import goods notes and drop ship notes (real-time) interaction, should ensure that shipments are Imported into Magento in a timely manner