parameter 34 length measurement 34 the value determined in the two or three steps is included in the feed back control as follows a value variable which represents the position of the pile compensating roller 5 or the warp tension of the pile warp as well as the base speed of the pile warp let off device needed for maintaining the pile warp tension is produced by a reference actual comparison via the first feed back controller 26 and is applied to the first input of the second feed back controller 30 the predetermined value for the loop to be woven which was calculated in advance is included as the second input of the second feed back controller 30 so that the value represents the speed of the warp let off device needed for making available the length of pile warp yarn required for loop formation this value forms a guide size for the third feed back controller 35 which via a reference actual comparison regulates the speed predetermined by the guide size as already mentioned terry weaving takes place with the aid of programmable reference pattern data the reference pattern data can be stored and changed with the aid of the control unit in order to optimize the course of the process and consequently also the terry weaving the reference pattern data which is stored after the so called patterning forms the basis for the production of a cloth the reference pattern data is stored in the control device and as a rule has to be changed to correspond to the warp yarn pile warp yarn and weft yarn being used in order to provide optimum production conditions these changes are made with the aid of different.