I was using RSLinx to connect to a “virtual” PLC with Rockwell Emulate 500. I used the OPC-DA module to allow Ignition to connect to RSLinx as an OPC server. The problem I was having was that data written to a tag in a script with writeToTag would not show up in the tag. I was using a tag change script to parse data from a TCP message and write to my PLC in a string tag. I was able to write data to the string tags from screen components and by manually typing data into the SQLTags viewer. It just would not work with the writeToTag function. I verified my script was actually working. I ended up connecting a ML1100 to my network and changing my tag to point to it using Igntion OPC-UA (same string file address, same program running as emulation) and it worked just fine.
Go ahead and attach up a log export (Configuration --> Console --> Export Logs) and I’ll see if anything jumps out.
Also, I’ll see if there is anything we could turn on logging-wise to get even more information from the OPC-COM module.