Make Labview talk Modbus through Lookout OPC Server

[Craig Nowak]

The final result I'm trying to achieve is to have LabView 6i talk modbus to one controller as part of a test. I've tried demo versions of BusView and Modbus-Link, which are third-party add-ons for LabView to make it talk Modbus, but they both only partially work (could be my fault, but the documentation is thin). I have a copy of Lookout 4.5 at my disposal, and I would like to have it run as an OPC Server so I can use a datasocket to communicate through it to my controller (that's what I've gathered from the postings). I've downloaded the example program at http://digital.ni.com/public.nsf/websearch/ea15f53db6fecca5862567240064df09 but it's wants a file called 'OPC to URL.vi' which I don't have.

I don't k
now much about lookout, so my question is how do I set it up to be an OPC server so I can get it to be the go-between for LabView and the controller. Both Lookout and LabView will be running on the same PC, which is running Win98SE.

[Chad_Pelletier]

Lookout, for the simple purpose of acting as an OPC server is very easy to configure. However, this procedure will only work with a developement version of Lookout.

First start Lookout and open a NEW process. Next, go into edit mode and create a Modbus object (Object>>Create). Configure the Modbus driver according to your specific system requirements. Click OK on the Modbus object properties panel. Finally, save this process by going to File>>Save As.

At this point, Lookout is ready to act as an OPC sever and allow you to access the Modbus driver through an OPC/Datasocket connection. This Lookout process must, however, remain running to continue this functionality.

For more information, please review the valuable information found in the Lookout Online Help which
was installed with Lookout. There you will find tours, tutorials, examples, and reference materials that are vital to understanding Lookout.

Chad Pelletier
Applications Engineer
National Instruments