A machine (1) for making liquid and semi-liquid products comprises: - a container (2) for processing said liquid and semi-liquid products; - a mixer (3) operating inside said processing container; - a heat exchanger (4), operatively associated with the processing container (2) for exchanging heat with the liquid or semi-liquid product inside the container (2); - a motor unit (5) operating on the mixer (3) for driving it in rotation inside the container; - an inverter (6), connected to said motor unit (5) for controlling the operation of said motor unit (5); - a control and operating unit (7), connected to the inverter (6) for sending command signals (S1) and receiving control signals (S2), - a communication fieldbus (8), interposed between the inverter (6) and the control unit (7) for allowing the transmission of said command and control signals (S1,S2) between the inverter (6) and the control unit (7), said machine being characterized in that the control unit (7) is programmed to run a first algorithm of the state machine type configured to control the inverter, comprising the following states: - transmission of a command to the inverter; - standby for confirmation that the inverter received the command; - transmission of a read request for an inverter operating parameter; - standby for receiving the inverter parameter.