connecting 7i96s to 2-wire RS485 using Pktuart

I have a 7i96s rev E that I'm trying to connect to a WJ200 VFD. The VFD  uses a 2-wire RS485 interface with pins labeled SN and SP.

How should I connect this to the 7i96s i/o pins?  What position should W7 be in? 

Thanks,
BR

 

This is described on page 11 of the 7I96S manual

basically:

RX-/TX- connect to RS-485 "A"
RX+/TX+ connect to RS-485 "B"
W7 right