Abstract: A yarn runner-length controller for warp beam knitting machines utilizes information of the yarn unwinding rate from a warp beam section and continuously compares this information to a signal related to the desired runner-length of the yarn. This continuous comparison yields an error signal with a magnitude proportional to the difference between the desired runner-length and the actual runner-length. The error signal is sampled and this sampled error signal activates a control device operating on the angular velocity of the warp beam section so as to adjust this velocity in the direction that reduces the difference between the actual runner-length and the desired runner-length. The magnitude of the sampled error signal is reduced to zero before the next sampled error signal is received by means of a signal from the control device related to the amount of adjustment made to the beam section's angular velocity.