Lookout has a ASCII object. You can send and receive regular strings/commands through a COM port. Therefore, I could imagine that you might communicate with your devices.
If your devices would support some common protocol you might use a specific driver (e.g. modbus, profibus).
There is a general posted message about using the ASCII object on this forum, which might help, too: http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=5065000000080000006E370000&UCATEGORY_0=_9_&UCATEGORY_S=0
Hope this helps
Roland