Hello Magnus!
I cannot really answer your question since I have no experience whatsoever regarding the board from Advantech. However I have found a couple of links that might be useful.
http://digital.ni.com/public.nsf/websearch/DF02F9489CE694AD86256A19006FFF3F?OpenDocument
http://digital.ni.com/public.nsf/websearch/24CAAA2C1178607686256E0B00815E5C?OpenDocument
http://zone.ni.com/devzone/conceptd.nsf/webmain/CB89EA4F427E0D9386256C4600448FC7?opendocument
These documents cover termination, general troubleshooting and using third party devices on a RS-485 network.
Regards,
Jimmie A.
Applications Engineer
National Instruments Sverige AB
Regards,
Jimmie Adolph
Systems Engineering Manager, National Instruments Northern European Region