Results of the analysis of various methods of the control and management of process of generation and maintenance of the defined side ledge thickness of coffered pyrometallurgical units are resulted. Experience of new method application on Vanyukov furnace as an example is described. The block diagram of the device and the recommendation about a rational arrangement of its elements in a zone of generation of the discernible samples indirectly reflecting the melt viscosity for skull formation are given. The authors suppose, application of the offered technical solution will allow to raise dynamic accuracy of stabilization of formation and maintenance of the defined side ledge thickness, provided with that fail-safety and durability of operation of considered type of pyrometallurgical furnaces.