Two month ago I spent a day to code a little vb application that read/write a integer to a slc 5/03 via OPC. I first try to do it with VB.net... But I found on AB.com that VB.NET is not supported with RsLinx prior to 2.50. I was working with Rslinx 2.41, so I switch back to VB6 and everything works fine. So be sure to use RsLinx 2.50 to test your VB.NET