The following notes can help quickly localize line errors:

  • If a supposed loop is not recognized as a loop: Try to localize the location of the fault starting from the start of the loop or end of the loop.
  • If a loop exhibits only an open circuit on the plus conductor, its position can be found by the distance of the end of the loop from the line tester. The resulting stub then runs only as far as the error location.
  • If the FDUL221 is operated without a PC, to and extent it offers greater functionality:
    • The resistances of the loop circuit and short circuit to earth can be read in directly.
    • The line charging current is measured and displayed.
    • For a line with a short circuit (disconnected by a separator) periodic attempts are made to close the separator so as to detect disappearance of the short circuit.
    • The functions for the DS11i Migration are not available on the FDUL221.
  • Certain devices on the line, such as devices adjacent to a line error or devices in a location not expected by the topology, can easily be identified by once the detector indicator has been set.
  • When during installation the detector ID is entered on the building diagram, the cable routing on which the detector ID is entered can be determined by means of the topology tree.
  • Check long stub branches be checked for correctness before they are connected to the loop.
  • If special cabling problems arise, the start and end of the loop can be switched and additional insights obtained when the topology is read in.