SEWING MACHINE AND METHOD OF OPERATION FOR SUCH A SEWING MACHINE

A sewing machine is provided to make tension of yarn automatically suitable for a stitch length which is set up by a control device by connecting the control device to a yarn tension unit and to increase flexibility. A sewing machine contains a conveying unit(14), a mechanical top transfer control device, a mechanical lower part transfer control device, a top transfer adjustment driving part, a lower part transfer adjustment driving part and a control device. The conveying unit comprises one or more top transporters(15) and one or more lower part transporters(16,17) and intermittently transfers fabric. The mechanical top transfer control device controls a transfer length of the top transporter. The mechanical lower part transfer control device controls a transfer length of the lower part transporter. The top transfer adjustment driving part controls the top transfer control device. The lower part transfer adjustment driving part controls the lower part transfer control device. The control device is signal-connected with the lower part transfer adjustment driving part and the top transfer adjustment driving part. This control device has the storage unit storing adjustment data allocated to sewing procedures.