HELP: OPCUA Connection Path DH+

I’m trying to connect to a SLC -5/04 and have been unsuccessful so far.

My current settings are
Connection path: 1,2,2,,1,1,3,5

I think 3 is correct for channel B from reading the documentation here:

The status just continues to say determine protocol.

The conection path in RSlinx looks like this:


Thank you for any help.

Unfortunately none of our AB drivers can route through an additional ethernet gateway like this. You’ll need to use another OPC server (Kepware, RSLinx).

Ok, I have added RSlinx as a OPC-DA COM connection. I can see all of the tags and topics I have created, but the tags I have added to the designer is showing an uncertain_InitialValue.

Any ideas? I just got the OPC-DA connection added so I have not done much research yet.

Thank you Kevin!

If this isn’t any help I’d just give support a call.

That ought to be relatively easy to support … if the “address” of a port/address pair doesn’t parse as an integer, just generate a byte array address with the ASCII as the bytes. If you want better error messages, you could constrain it to valid FQDNs or IP addresses, but you can let the first hop turn it into an error message for you.

There’s a lot of horrible, hardcoded assumptions in the legacy AB drivers that make something that should have been trivial into something difficult and dangerous to implement without breaking things.

The new Logix driver can route any path like you’d expect, but that doesn’t help here.

I can read the tag successfully from OPC → OPC Quick Client, but not in the designer. I followed all the permissions updates from the link you provided.

Also how do you read the bit out of a word? for example the tag looks like this: B3:90.1


The remaining difference is that the QC is doing reads, while your tags in the designer are using a subscription.

I don’t know. Since you’re connected to RSLinx, whatever syntax that would be, if any, depends on the server. Try appending “.1” to the OPC Item Path for starters.

edit: ah, but you’ll need to get the tags outside the QC working first. You can create a new tag group (scan class pre-8.0) and set it to OPC Read Mode, and then add your tags from RSLinx to that for now.


After completing the permissions in the Link that Kevin provided. I still couldn’t get the tags to show so I called it a day and shutdown my work station. To my surprise everything worked the next day. I would like to say the reboot applied or reset something that made this work correctly.

Also for getting a bit from a word if you just copy the value from RSlinx and paste it into the tag editor --> OPC Item path. It looks like this: [TOPIC]B3:3.0,L1,C1