I read somewhere that while the HuangYang VFDs do not talk modbus, this Yalang one actually does, and my experience with the logic analyzer and message interaction would agree. The messages it returns are well-formed modbus and consistent. The LCD control panel connection also uses standard modbus, but at a fixed baud rate (38400 in my case) that is not user-configurable. I used the logic analyzer to watch the traffic between the LCD panel and the main board, and when I imitate the panel my messages are responded to correctly, but the motor never moves.
As for the usual RS485 port, it always responds with "Illegal data value" no matter what, even when only attempting to read. I wrote a script that tried to read all registers from 0-16384 and every single one failed with the same result. It's almost like the firmware is either bugged or never intended to accept traffic on that port in the first place.
