When I write to a tag a stored value (constant) It works fine but when I grab the data from a user (eg. spinner) It doesn't work
tag = "[default]setPoints/setPoint.value"
value = "event.source.parent.getComponent('Spinner').intValue"
system.tag.writeBlocking([tag],[value])
You are assigning that whole thing as a string to value
. Take off the outer double quotes.
If this isn't Vision, you'll need to learn to copy and paste from compatible examples.
Also, this is implied if you don't include it, so easier to just leave it off
Thank you for your help. It is a vision application.
I have turned around the issue by using a memory tag as a middle layer.
Wish you have a good day 
What do you mean, middle layer ? You shouldn't need any middle layer.