16Installation3.7 Instrument connections3.7.1 External powerWARNINGWhen using an external power supply to power the instrument, ensure the externalpower socket is earthed.In addition to the internal rechargeable battery pack, the instrument can be powered by anexternal power source using the supplied adapter and cable. Connect the adapter to the powersupply connection socket on the instrument (in Figure 4 on page 14), and plug into an externalpower supply socket.Note: When the instrument is connected to an external power source, the internal battery pack isautomatically recharged.3.7.2 RS232 connectionThis connection can be used to download measurement data and for real-time monitoring of themeasurements.The data sent to the PC via this link is identical in format and content to that stored in themeasurement file on the instrument and which can be transferred using the USB mass storagedevice (see Exported files on page 36 for details).3.7.3 USB connectionThe USB connection (in Figure 4 on page 14) is used for exporting and importing data from andto the instrument. Tables can be set up on the PC using the 3100 PC software application andthen uploaded to the instrument using a USB mass storage device.In addition, tables can be exported from the instrument to the USB storage device and thenimported to other 3100 instruments to standardize configurations.For more details on this, refer to Import / Export on page 35.