System for controlling warp let-off motion of weaving machine during machine downtime

A weaving system comprising

• a warp beam,
• a main weaving mechanism, combined with said warp beam, for moving periodically so as to repeat a weaving cycle, said main mechanism being capable of operating alternately in a normal weaving operation mode and a slow operation mode,
• a driving shaft which is driven in synchronism with the periodical movement of said main mechanism,
• first drive means for driving said warp beam in said normal operation mode by transmitting power from said driving shaft, said first drive means including speed change means capable of changing the speed of the warp beam rotation, said first drive means including first clutch means for connecting and disconnecting the driving connection between said driving shaft and said warp beam through said first drive means,
• second drive means for driving said warp beam in said slow operation mode by transmitting power from said driving shaft, said second drive means including second clutch means for connecting and disconnecting the driving connection between said driving shaft and said warp beam through said second drive means,
• first sensing means for sensing the periodical movement of said main mechanism,
• second sensing means for sensing the rotational movement of said warp beam, and
• control means connected with said first and second sensing means, for determining, during said normal operation mode, a quantity indicative of an angular displacement of said warp beam per weaving cycle in accordance with signals produced by said first and second sensing means, storing the determined value of said quantity, and controlling the warp beam rotation during said slow operation mode by controlling said second clutch means in such a manner that said warp beam rotates only through an angle equal to the stored value when said main mechanism is moved through one weaving cycle during said slow operation mode.