A tank gauging system for sensing product parameters of a product contained in a tank is disclosed. The system comprises a microwave-based level gauging unit and a temperature gauging unit. A controller of the system includes an external interface adapted to enable communication between the tank gauging system and an external control system; processing circuitry configured for management of communication over the external interface; and a power supply, which is configured to supply intrinsically safe power to the gauging units, wherein the power supply has an improved output characteristic. Further, an intrinsically safe two-wire bus connecting the controller and the gauging units is provided, wherein the two-wire bus is usable both for transmitting measurement signals related to the sensed product parameters from the gauging units to the controller and for providing intrinsically safe power from the controller to the gauging units.