To All,

I'm missing something in my basic understanding of DDE/OPC. I have a PC running RSLinx/RSView talking to a PLC-5/11 over Ethernet thru a NET ENI Module. Reading of data from the PLC5 by RSView via RSLinx works, using DDE and or OPC. However, I would like to be able to have the PLC% send unsolicited data to the PC rather than poll it. The message from the PLC5 is good (confirmed with serial and ethernet sniffers) but the RSLinx package rejects it with a 4F 10 (10) My problem I am pretty sure is that I am not setting up my "Hotlink" to RSview correctly. "Active Topics in RSLinx shows that I have a valid connection but I can't seem to see the unsolicited data anywhere (RSView or RSLinx) I've done web searches and looked at Rockwell's Knowledgebase/manuals but haven't found anything but big hammers to smack myself in the head with.

thanks,
Brendan Kirby

 

Have you checked the "Unsolicited Message" box in the OPC topic configuration? The type of message you are setting up is in fact an unsolicited message, versus a polled message.

 

Brendan,

Have you used the RSLinx OPC test client? This is included with RSLinx Pro and up. Experiment with this and see if you can get what you want. It's a good diagnostic tool.

Do you understand the "data_change" event?
Rockwell has a good VB6 demo with source. I think OPCpartial1.zip --- search ab.com it's in a KnowledgeBase.

Mike.