fixed thread guide elements 41 and a main nozzle 42 further on this screen a progress bar 43 is shown that can represent the position of the main shaft of the loom in this progress bar 43 the position of the main shaft of the loom is represented by the position of the borderline 44 between a filed up section 45 and an empty section 46 furthermore the weft thread 47 is shown if the position of the thread brake elements 40 is determined as a function of the position of the main shaft of the loom for example by using the position sensor of the motor for controlling the thread brake elements 40 the position of said thread brake elements 40 can easily be determined as a function of the main shaft of the loom furthermore the maximum tension that the weft thread can stand without a real danger of breaking is for example entered into the machine terminal or the central server according to an example of the aforementioned thirteenth aspect of the invention the screen 17 shows for each position of the main shaft the progress bar 43 as well as the thread brake elements 40 in.