I have a transaction group with a run always trigger expression tag using the hasChanged function on a OPC item from the same transaction group.
hasChanged({[~]FillerMode}, False)
this should go true only when the value changes not the quality or timestamp.
my problem is the tag never goes true when the value change. Can this function not be used on a OPC tag?
I setup a test with a memory SQLTag used in the transaction group and changed the memory tags value. The expression then evaluated true and the transaction group triggered.
does the function only work with SQLTags?
Thank you,
I solved my own problem, but I am posting a reply in case somebody runs into the same issue or Inductive can see a way of stopping it from being a possibility in the GUI.
the issue is because I have a OPC tag named FillerMode that is set to read only and I also have a triggered expression tag named FillerMode that is bound to my OPC Tag. even though the tags appear different when you browse the tags in the group the expression syntax referencing the tag is identical.
{[~]FillerMode}
{[~]FillerMode}
the group was triggering on the triggered expression tag FillerMode and not the OPC FillerMode. since the group could never be triggered because the triggered expression would never be evaluated the group was stuck.
I think the run always group should always evaluate tags starting from the the OPC group to the run always group in the order on the screen or sum how restrict tags with the same name in a transaction group.