An automatic milking system having a vacuum pump arrangement, the automatic milking system includes a milking system controller arranged to control milking system parameters and a vacuum pump arrangement having a vacuum system controller for controlling vacuum system parameters. Communication means is coupled to the vacuum system controller and to the milking system controller for establishing communication between the vacuum system controllers and the milking system controller. The milking system controller has signal transmitting means for transmitting a message to the vacuum system controller. The vacuum system controller has signal receiving means for receiving the message from the milking system controller, and the vacuum system controller is arranged to change a least one of the vacuum system parameters depending on the received message.