Abstract: A system for controlling tension improves carpet quality by maintaining tension along a primary backing material at a constant value. The system controls the tension by maintaining the speed of an entry pin roller slightly slower than the speed of an exit pin roller. The exit pin roller is driven with a main drive motor while the entry pin roller is independently driven by a separate vector drive motor. An encoder, coupled to the exit pin roller, is driven in synchronism with the exit pin roller and produces a pulsed output which is converted into an analog signal representative of the speed of the exit pin roller. A controller receives a user-defined desired value of tension and monitors outputs of a pair of load cells to determine the amount of tension actually on the primary backing material. Based on the difference between the actual value of tension and the desired value of tension, the controller produces a control signal which is fed to a drive circuit.