Method for determining the position and shape of a yarn fed to a textile machine

A method for determining and monitoring the state of movement or stoppage of a yarn fed to a textile machine by using an optical scanner, comprising

• arranging a light source to provide a cone of light,
• arranging a photo-sensitive receiver within said cone of light and opposite to said light source such that a sensitive region is defined therebetween,
• coupling said light source and said photo-sensitive receiver in a circuit,
• passing a yarn to a textile machine through said sensitive region such that the yarn causes a shadow region on said receiver,
• determining a variation in at least one of the shape and position of the yarn passing through said sensitive region,
• generating a first electrical signal and a second electrical signal on the basis of a variation of the shadow region on said receiver corresponding to the variation in at least one of the shape and position of the yarn,
• converting the electrical signals to an output signal, and
• passing the output signal to an operating member of the textile machine, said operating member of the textile machine being selected from a group consisting of an indicator for indicating the state of movement or stoppage of the yarn and a machine control circuit.