Pepperl+Fuchs has developed the FieldConnex Fieldbus Diagnostic Handheld (FDH-1) to simplify the installation and handling of the fieldbus infrastructure. The mobile device can be operated without expert knowledge; a single press of a button is all it takes to carry out the measurement. The handheld is connected to any fieldbus segment and, as a stand-alone solution, does not require a PC to work. In this way, it shows whether there are faults in the installation, where they are located and how they can be rectified even before a segment is commissioned. The handheld can also be used to check whether existing cables can be used for a fieldbus installation. For existing installations, the device can also check the function of the short-circuit protection on the connections for the spur lines. The handheld has an integrated expert system that interprets the measured values. In addition to this system, a 'Commissioning Wizard' with guided dialogs ensures user-friendly operation of the handheld. This compares the installation with the values from the planning and can thus carry out a target/actual comparison.