Trying to script a data change event to update a dataset in a List

Ignition
1 
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.
	"""
	
	print "currentValue", currentValue.value
	window = system.gui.getWindow("OPCUA Monitor 1 Root")
	dataset = window.getComponentForPath("Root Container.MessageLog").data

	#dataset = event.source.getComponent("MessageLog").data
	pdataset = system.dataset.toPyDataSet(dataset)
	pdataset.addRow([currentValue])
	dataset = system.dataset.toDataSet(pdataset)
	window.getComponentForPath("Root Container.MessageLog").data = dataset
	#event.source.getComponent("MessageLog").data = dataset

Even though system.gui autocompletes it is telling me that “gui” does not exist.

Error executing script.
Traceback (most recent call last):
  File "<tagevent:valueChanged>", line 4, in valueChanged
AttributeError: 'com.inductiveautomation.ignition.common.script.Imm' object has no attribute 'gui'

I am at a loss as to why I cannot do this.

2

Tags are gateway-scoped “global” resources that do not belong to any project.

You can’t reference any client-scoped scripting functions or try to interact with a Vision window like this.

1 Like
3

How do I update a dataset based upon a tag value change? Can datasets be in the same scope as tags?

4

It looks to me like you just need to bind your table’s data property to that tag value.

1 Like
5

You are right. I needed to bind a memory dataset tag to my List. Now I am trying to update the memory dataset by adding rows. Each time the value changes I need to add a row. So it acts like a message log:

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.
	"""
	
	tlist = ["MessageLogDataset"]
	
	tags = system.tag.readBlocking(tlist)
	print tags
	print currentValue.value
	for tag in tags:
		dataset = tag.value
		break
		
	system.dataset.addRow(dataset,0,[currentValue.value]) 
	system.tag.writeBlocking(tlist, [dataset])

I don’t get any errors, it does not update the dataset tag (even though the tag initiating this event does update), I never see the print values. The only time I see info is when it tells me there is an issue with the script in the tag properties window. How do i get tag scope print messages to show in the console?

6

Kind of out on a limb here, but perhaps the fact that “tag” is used as a parameter in the function definition and you use it as the loop variable, things aren’t working as expected?

7

All of the dataset manipulation functions return a new dataset; they don't modify the existing one. You need to write the new dataset value you get from calling this function.

1 Like
8

I was 99% there! Thank you for that last 1%! Which usually takes 99% time.

9

Also your print statements made in gateway-scoped code will end up in the wrapper.log files where the gateway is installed.

You can get statements into the logs page on the gateway by using system.util.getLogger: system.util.getLogger - Ignition User Manual 8.1 - Ignition Documentation

You won’t get gateway-scoped logging of any kind in your client or designer.

2 Likes