Systematic control of the rheological behavior of the rovings in an installation facility dynamometer constant elongation gradient is proposed in this paper. It is an application for all types of spinning both short fibers as long fibers. Industrial experiments conducted show that this control drawing of the spinning frame is optimized, getting more regular yarns mass with greater industrial profitability. This work is applied to a spinning worsted manufactures fine yarns with high quality requirement The fundamental thesis of our wor is that the rheological control of the roving, output from roving frame, either torsional or friction, helps to increase the profitability of the spinning frame and get higher quality yarns. Rheology is the science of movement of the fibers within a fibrous vein, ie a sliver or roving from the graph tribocharging-elongation another fundamental concept appears in our analysis: the isocarric elongation. Empirically, we defined this elongation as the difference between the elongation percentage corresponding to half the determined maximum tribocharge on the ascending and descending branches of the tribo-charging-elongation curve. The application of these techniques to former machines to roving frame in conventional wool process also allows us to adjust the machines with more speed, reducing the time and product (waste) required a change in manufacturing. To increase, for example, the feed of a gill, increase the difficulty for drafting in the following step. These difficulties are directly related to the value of the doubling and drafting that applies: the more doubling and drafting, the greater the difficulty in later steps