Error Accessing OPC Items in MOD 300 LOOPFCM Display
When you try to open the loop template if an MOD 300 LOOPFCM display, you get a popup error stating Error Accessing OPC Items with a list of items that cannot be accessed .
In this example, it is ENGUNITS
Continuing on, the loop template is displayed without the Engineering UnitsSymptoms:
In order to correct the problem, you will need to find and delete the duplicate exposure.
To find the duplicate exposure, you can use the PG2 graphics editor.
Open any PG2 graphics or create a new one. You will not need to save any changes you make on the graphics as you are only using the editor to explore for the duplicate exposure. When finished, close the graphics editor without saving.
In the PG2 graphics editor, open an Expression Editor on any property. Under the Propery tab, navigate to the loop you are having the error with LOOPFCM. With this example you will see two entries for ENGUNITS. Double clicking on each will show you the sources of each.
In the above we see that there is a source fro MOD OPC Control Connection and Property Translations
In Control Structure, you see highlighted the two sources and the contents of the Property Translations
Deleting the exposure in the Propery Translations would eliminate the Error Accessing OPC Item error. This example was created by adding a Property Translations aspect to the loop to create a double exposure. Similar exposures can be created in other structures such as the Object Type Structure.
In this case, deleting the Property Translations aspect resulted in the correct display of the loop template