Abstract: A method for on-line monitoring and/or control of an electric arc furnace utilizing a method of data transfer between a programmable logic controller and a microprocessor comprising monitoring data from the furnace over a fixed time cycle, assigning data values to the monitored data during such time cycle, dividing the fixed time cycle into a multiple of N time subintervals, dividing the data values into data subsets, assigning designated time subintervals to each of the data subsets, transmitting data to the microprocessor in each time subinterval to execute program code corresponding to the data subset in such time subinterval and calculating control factors from the transmitted data for providing control information.