OPC tag definition

Ignition
1

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.

2

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.

3

@JordanCClark
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.

4

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

5

@JordanCClark

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.

6

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
7

@JordanCClark

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

8

@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?

9

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
image

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