Check String Parameter to Enable/Disable Tag

Ignition
1

I have a string parameter that is used in the OPC path of a tag. I want to disable the tag if the parameter is not provided (empty). My binding on the enabled property of the tag looks like so:

!( isNull({Read_Tag}) || {Read_Tag} = "" )

I'm not sure if an empty string returns "", or Null, so I used both.

I get a configuration error on the tag:

Error_Configuration("Bad_AttributeIdInvalid: The attribute is not supported for the specified Node.")

Is there something wrong with the binding?

2

You can't use expression language in the binding of the enabled property, unfortunately. Fortunately, you CAN just use {Read_Tag} and it will cast any non-empty string values of your property to "True"

3

If that's the case, it really should stop highlighting expression statements as if the expression syntax applies. For instance:

image
"if" should not be highlighted as a function if this is not the expression language.