OPC tag definition

I have ignition setup communicating with rockwell PLC via Rslinx OPC.

in the tag definition, I need to enter the “OPC Server” and “OPC Item Path”.

Currently I need to enter these values either manually or via the parameters in the UDT.

Just wondering whether I can create a new tag folder called “Global” to store the OPC server name and device name. Then I can call these values when defining the OPC tags? So the OPC Item path will become {OPC Server Name}{OPC Device Name}.xxx. These indirect address should be from another tag instead of parameters of the UDT which I am currently using.

So I have a central place to look at or modify if I am switching to another OPC server with a different name later. It will make tag changes much easier.

Thanks in advance.

You didn’t mention what version of Ignition you are using, but UDT’s would fit the bill.

for switching OPC servers, I have successfully used Find/Replace to do this.

I have a similar issue that need to change the OPC Server for a lot of tags dynamically during the runtime.

How could I achive it if not using system.tag.confiugre()?

my version is ignition 8.0.4 nightly.

If you’re doing it during runtime, you must use configure.


Thanks for your info
The parameters setting is not so convenient as the previous system.tag.editTag.
The first parameter is basePath, not the tag path itself.

You can use the tag path as the basePath.

tagName = '[default]path/to/tag'

tagConfig = system.tag.getConfiguration(tagName)[0]

tagConfig['opcItemPath'] = 'new_opc_item_path'

system.tag.confiure('', [tagConfig])
1 Like


Thanks for your suggetsion.
The usage of [0] in system.tag.getConfiguration(tagName) is really useful. :slight_smile:

@JordanCClark i am using 7.9.12 I defined the OPC server name as a parameter in a UDT. However, when i exported instances of the UDT, I do not see any reference of the opc server parameter. Because of that, i can’t do find and replace for bulk changes. Any thoughts on this?

After defining the OPC server name as a UDT parameter, you need to use while referring to a tag
Here’s what it looks like for me in Ignition 8.0

Then you can read the tag configuration from the one you changed and change the rest via a script that Jordan recommended.