Create list of tags to use for tag history query

Ignition
1

Whats the best way to create a list of tags I can use for tag history query that will allow me the ability to dynamically do the query so additional tags may be added but i won't have to change the code.

I currently created a list with tag paths manually:

	tagpaths = ['[PLC]AnalogInputs/FT101/InputValue', '[PLC]AnalogInputs/FT201/InputValue',
		'[PLC]AnalogInputs/PT200/InputValue', '[PLC]AnalogInputs/TT200/InputValue',
		'[PLC]AnalogInputs/TT201/InputValue', '[PLC]AnalogInputs/VT101/InputValue',
		'[PLC]AnalogInputs/VT201/InputValue', '[PLC]AnalogInputs/VT202/InputValue']

I want to be able to iterate through a tag folder, find each UDT tag, and then create this list with all of the UDT's present in the folder.

Here are the tags I want to go through in the AnalogInputs folder.

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I have tried using system.tag.browse to try to create this list but can't get it to work.

2

If you post your code we could try to find where you went wrong.

Regardless, here is a quick example of a function that does such a thing:

def getTagPaths(path):
	fltr = {'tagType': "UdtInstance"}
	tags = system.tag.browse(path, fltr)
	return [str(tag['fullPath']) + "/InputValue" for tag in tags]
1 Like
3

Awesome! Took your example and implemented directly

One question I had was about the filter. I am trying to understand why this part is needed?

Here are the results:

image

image

4

Ah I see. This filters out any tag that is not a UDT tag. In my case every tag in the folder is a UDT tag therefore I don't necessarily need it but if I did add a tag within that folder that wasn't a UDT tag it could cause issues...thanks!

1 Like
5

You could also specify what type of UDT you want:

filter = {
    'tagType': "UdtInstance",
    'typeId': "your_udt_name"
}

In case other types of UDTs ever get added to that folder.

2 Likes