Method of contactless optical detection of yarn at a workstation of a yarn manufacturing textile machine, an optical sensor of yarn and a textile machine

An optical sensor for detecting a yarn at a workstation of a textile machine, comprising:

• a sensing slot;
• a radiation source disposed to transmit sensing radiation across the sensing slot;
• an optical sensor disposed at a distance opposite the radiation source, the optical sensor comprising at least one row of radiation sensitive elements arranged next to each other;
• a monitoring and evaluation device configured to monitor and evaluate a state of the yarn in the sensing slot including a position of the yarn and a diameter of the yarn;
• the monitoring and evaluation device connected to a device for stopping the workstation upon detection a yarn break by the monitoring and evaluation device;
• and
• the monitoring and evaluation device further configured to detect a change in the position of the yarn or in the a time course of the position of the yarn corresponding to a yarn break before an end of the yarn break passes through the sensing slot.