I have a lot of experience with using the FTDI rs485 cables to talk to yaskawa ac drives. I like the node-red-contrib-modbus package myself. It's very simple and has a lot of tweakables.
In your case, it looks like you should have everything you need in your python file to make this work. The biggest thing that messes people up with serial connections is the wiring. Does this controller have separate rs232 and rs485 ports? Most don't. On yaskawa drives, one must jumper the S+ to R+ and S- to R- for rs485, since it uses a differential signal. Also, don't forget the commond wire, which should bond both the Pi and the controller to the same ground potential.
