A thickness detecting sensor can widely set a dynamic range for detecting the thickness of a medium, and exactly detect the thickness of the medium even when the dynamic range is widely set in this way. The aft segment is made of metal and can define the trailing edge of the vane assembly. The machine includes a tensioning device for frictional engagement with the web, an inflation arrangement for inflation of the preformed pouches, a sealing arrangement, and a clamping arrangement. The UART circuit also includes a multiplexer coupled to the hands-free functional part and the UART2 at respective receiving and transmitting ends, configured to perform switching operations based on at least one control signal transmitted from the processor.