Mixing apparatus comprises a continuous mixer supplied with ingredients by a plurality of speed controlled motor driven pumps and having flow meters providing signals representative of ingredient flow rates. A programmed digital computer controls the pump motors in response to any differences between actual flow rates and selected reference flow rates so as to maintain the actual flow rates substantially at the reference values. The reference values are set into thumb wheel switches on a control panel having devices for displaying the actual flow rates or the errors between the actual and the set-in rates, and a plurality of switches selectively settable to establish the mode of operation of the apparatus. The computer periodically determines the set-in flow rates and the switch settings and updates the information displayed on the panel. The computer also detects the occurrence of malfunctions and initiates actions to warn the operator thereof and to shut down the apparatus automatically if required remedial action is not taken by the operator in time.