A machine for making liquid and semi-liquid products includes a container for processing the products, a mixer operating inside the container, a heat exchanger, operatively associated with the container for exchanging heat with the product inside the container, a motor driving the mixer, and an inverter, connected to the motor for controlling operation of the motor. A control and operating unit, connected to the inverter sends command signals and receives control signals. A communication fieldbus, interposed between the inverter and the control unit allows transmission of the signals. The control unit is programmed to run a first algorithm of the state machine type configured to control the inverter, include 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.
