A system and approach of importing data from site controllers as history imports with a history service by a supervisor in conjunction with a host processor. The history service may reconfigure the history imports to provide the history service virtually full control over the history imports. The history service may runs a history import cycle to ensure that virtually all enabled history imports are performed. The history service may establish a list of history imports to be processed at a beginning of the history import cycle. The history import cycle may query virtually all history imports in an order on a last success time of a history import operation where an oldest time is first on the list. The history service may ensure a maximum number of history imports are running by querying for a count of history imports of an in progress state.