OPC server read/write commands from opc client

Can I connect to Ignition and use it only as a passthrough of data to my opc client.

I want to set up some tags and not have ignition subscribe to them. They should just set there until I issue a read/write from my client.

Sure, by default if you connect to Ignition’s OPC UA server you’ll see any configured devices and the nodes underneath if that driver/protocol supports browsing.

If you want to see Ignition Tags that you have created in Ignition, you have to enabled the “Exposed Tags” functionality.

Thanks for the quick response.

Can you point to where in the documentation I can create tags and not have Ignition subscribe and gather data.

I’m not sure exactly what you mean.

If you create an OPC tag in Ignition it will be reading that data from whatever OPC server the tag belongs to.

If you just want to add a device and let your client see any Nodes that device adds to the address space then you just pick a driver and add a device instance, e.g. https://docs.inductiveautomation.com/display/DOC81/Connecting+to+Logix

Okay, re-reading this I think what you’re trying to do is use the OPC UA server as a “scratch space” where you define some arbitrary nodes to read/write from with your client.

That’s not really supported. The server doesn’t let you just define arbitrary nodes, they call come from a source like a configured device instance.

The closest thing to what you’re after would be creating a set of memory tags in Ignition and then exposing them via Exposed Tags, but those would definitely be visible and modifiable from Ignition as well.

I have created tags to my control logix plc by dragging over from the opc broser. I have over 3000 tags that read. I do not want igntion subscribing and reading these tags all the time over the network. I just want my opc client to read sections of the 3000 tags based on my client when it is needed. So I am wondering if Ignition is OPC server like kepware where it can just set there and I can issue read and write commands to it and my client is in control.

thanks for your help!

Yes, it’s like that.

But if you don’t want Ignition to be reading those values also then you need to delete the tags you created by dragging them over from the OPC browser.

Our company is replace kepware with ignition. So kepware will no longer even be around. But when I dragged the tags from opc browser that is connect to my AB PLC, I see them constantly updating. That is what I do not want to happen. I want my client to issue read and write command and Ignition just pass the data to and from my opc client. So how do I disable the subscribe

Thanks for your help

Like I said, delete (or disable) the tags you created in Ignition.

Any OPC tag you create in Ignition is going to be updating its value from the OPC server it belongs to.

Oh I think I understand. I do not need to create anything in ignition except connect to the device in the gateway?

Yeah, if all you’re trying to do is have it act like Kepware, just create devices in the gateway and nothing else.

ok Thanks a ton for the info!!!

If your client will be connecting from another computer you’ll eventually need to modify the Bind Address and possibly other settings, depending on your client: https://docs.inductiveautomation.com/display/DOC81/OPC+UA+Server+Settings

By default the server binds only to localhost. Changing the Bind Address to is usually good enough to allow remote connections. You will have to restart the gateway for any OPC UA server settings changes to take effect.

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ok Thanks!!!

http://localhost:62541 is this the server endpoint on my local computer?

I have a device called 3B_TEST I want to browse to and read from global.c_mts_handler…
what do I use for the node descrpitor?

thanks for the help

The discovery endpoint is at opc.tcp://localhost:62541/discovery and the session endpoint is at opc.tcp://localhost:62541.

The NodeId should be something like ns=1;s=[3B_TEST], and you can arrive at this and others by browsing from the standard OPC UA Objects folder to the “Devices” folder and then to each device underneath it.

You should use something like UaExpert to connect and browse around.