In the application with solar panel, the function MPPT (Maximum Power Point Tracking) maximizes the input power for various conditions of radiation and temperature. When radiation grows, pump increases the rotation speed as well as the water flow . When radiation decreases (presence of clouds or different hours of the day), pumps reduces the speed and thus the water flow but still provide water until the radiation falls below the minimum value to ensure the operation. Installation Wilo-Actun OPTI HS pump can be installed with External control module or without it, so becoming a “plug and pump” system. If no external control module is used, signal cables can be used to control pump ON/OFF the connecting, for example, a float switch All the protections against overload, overvoltage and dry running are integrated into the on board inverter. If the signal cables are connected to the External control module, it is possible to: Control the electric parameters (current, power, voltage). Record and store all the alarms related to the working hours. Connect a pressure or a flow sensor to control the pump performances. Connect a pressure or float switch. Provide an alarm digital output for remote control.