Tag Custom Property Access

[amarks]

I have a tag with a custom property defined. How do I access the tag’s custom property via scripting?

For instance, I have a tag called Output with the custom tag enableLogging. How would I access this property in a script, say a value change script?

tag.enableLogging.value? If so, custom property names are allowed to have spaces, how would this work with spaces?

[paul-griffith]

system.tag.readBlocking(['path/to/tag.propertyName']). You probably shouldn’t name them with spaces if you need to read them from scripting, though.

[amarks]

That’s what I figured. So, from the tag event script value changed scope, I should be able to use tag.propertyName.value, correct? or, just tag.propertyName?

def valueChanged(tag, tagPath, previousValue, currentValue, initialChange, missedEvents):
	"""
	Fired whenever the current value changes in value or quality.

	Arguments:
		tag: The source tag object. A read-only wrapper for obtaining tag
		     properties.
		tagPath: The full path to the tag (String)
		previousValue: The previous value. This is a "qualified value", so it
		               has value, quality, and timestamp properties.
		currentValue: The current value. This is a "qualified value", so it has
		              value, quality, and timestamp properties.
		initialChange: A boolean flag indicating whether this event is due to
		               the first execution or initial subscription.
		missedEvents: A flag indicating that some events have been skipped due
		              to event overflow.
	"""

[paul-griffith]

I think just tag.propertyName.

[amarks]

Where would errors/messages from this script be visible?

[paul-griffith]

You should see them in the tag diagnostics (an icon in the top right corner if you’re on 8.1.17+):

But with two properties I was able to read them directly off the tag object in the event script:

[amarks]

Thanks. I was also able to find it on the gateway here:

Is there an easy way to get rid of the nuisance The statement did not return a result set SQL error (when using system.db.runNamedQuery())?

[paul-griffith]

Switch your query type to Update?