Hi,
I've not used the DataTables API (like you posted above), but if you are looking to search a specific column then I would do it like:
var dt;
function createDataTable(){
dt = $('#CardsGrid_grid').DataTable();
}
function searchDataTable(search){
dt.columns(2).search(search).draw();
}
The above example searches the 2nd columns in your table.
... hope it helps.