Populating DB Reference properties of an Instance, based on a String expression.

[MarkPitout]

Hi There,

This might be a simple question (I hope so).

I am trying to build a template for an object that has three DNP3 points that are referencing 3 SCADAPack 47x configuration points. I am using a standard naming convention in the naming of the object and the configuration points. So for example:

• The Object will have a String parameter called Asset ID and this will have a value of "001-LIT-01".
• The configuration points in the SCADAPack will have names like  "001-LIT-01_CMD", "001-LIT-01_STS" and "001-LIT-01_EngVal".

How can I configure an expressions in the Template's Property Overrides, that automatically populates the DB references of the DNP3 points, based only on the string value of the AssetID property and perhaps a pointer to the folder that contains all the configuration objects?

See attached picture for reference.

[AndrewScott]

I don't believe there is anyway to do something like that.

It would require someway of concatenating strings to build up an object name and then evaluate the result to generate an object ID for the DB reference field, but there isn't anyway to do that. Even if there were, it would be quite brittle when faced with moving or renaming objects / groups.

[MarkPitout]

hmmm. A bit disappointing that DB references in template instances cannot be built up by string expressions.

Then I should maybe change my approach - move the SCADAPack 47x point configuration objects into the template, and simply point those objects at the base SCADAPack configuration object. The struggle will be to get the point config objects synchronized with the logic application, but it's worth a shot.

Let me play with that approach and see where it leads me.

[AdamWoodlandToo]

You could go old-school and write a ST or FBD logic program that runs when the instance is created, sets the required properties and then disables itself (interval to 0, and if ST call DisableExecution so it doesn't appear as active in queries). Logic doesn't execute in the template, only in the instance, so as long as the logic can access the parameters you need at the time of instance create you should be good. If you have to set something manually first, then set the logic to be a manual execution and trigger yourself when necessary.