ABEM Terraloc Pro 213Figure 5 The user interface panelThere are two LED’s shown through the LED Window:- The green LED indicates disk activity- The yellow LED indicates if sampling is on or offThe Power SupplyThe Terraloc Pro 2 can use an external power source as well as internal batteries aspower supply. The external source can be a battery or a PSU (Power Supply Unit). Ifpossible use the supplied cable set for the external power source. Both external andinternal power sources can be attached at the same time. In this case the internalbatteries will be charged if the external battery is charged enough. The power supplystatus is shown on the display (see chapter 4.4.7 Application Status Bar).For field operations a good, adequate in capacity and recently charged battery is vitalfor the best performance. It is possible to fully run the Terraloc Pro 2 without theinternal batteries but for your convenience you should always have at least one installed.The internal batteries is primarily designed as a backup power source for operating theinstrument during set up, data transfer etc, hence it cannot be used alone to power theinstrument for a days work.Once the instrument has been turned on and the external battery for any reason isdisconnected the instrument will automatically switch to the internal batteries. Thisuseful feature makes it possible to disconnect the external battery temporarily withoutshutting off the instrument when for instance moving from one place to another.