It might because that YUDIAN recently upgrade the firmware of AI-508 and the existing driver no longer works. If so, you may debug this version and update to the new version. And you are welcome to ...

The repository provides a driver for setting up a mass flow controller of the SFC6XXX family or a gas flow sensor of the SFM6XXX family to run on a Raspberry Pi over UART using the SHDLC protocol.