Read DMM DNY2 servo driver stored parameters using python
You are missing the communication protocol. I.e. What command you should send to get a proper response.
So, dig through data-sheets or you will have to reverse-engineer the software you got with the device. Which, perhaps won't be legal if the licence doesn't allow you to use the device with any other program except the one you received etc, etc.
If you cannot find the protocol specs in the data-sheets or on the internet, then install RS232 virtual card, make a loopback device so that you connect to one virtual port and the real port is connected to another and you can be a 'man in the middle' and see what data passes through when the software you got communicates with the device.
Enjoy!
Currently I'm working with DMM DNY2, the hardware come together with software. The software can read available port, assign port for servo and read stored parameters in servo driver.
Now, I'm trying to create python script to do the same as software, i can do for get and assign port, but can't get stored parameters in servo driver. each time doing read it return b''. 
Can someone help me, give me pointers what should I do or what I'm missing.