You can include any item in a Group Template, except the following:
- Another Group Template
- An Operator Document Store
- A Data Table
- A User
- A Script Library
- A Function Block Library
- A Structured Text Library.
If need be, you can Optionally Add Items Directly into a Group Instance. However, you need to be aware of the following:
- Any item that you add locally to a Group Instance will be automatically deleted if the Instance’s configuration is later changed to reference a different Group Template.
- You can add any item other than a Group Template locally to a Group Instance.
- If you add a Group Instance to another Group Instance, each of those Instances has to reference a different Group Template (a Group Instance cannot reference the Group Template of any Group Instance in its parent chain).
ClearSCADA supports Incremental Import. If you use the Import or Import & Merge menu options to import configuration from one ClearSCADA database to another, be aware of the following:
- The configuration of a Group Instance that is imported successfully into a database is compared to that of its Group Template (ClearSCADA automatically runs the Repair Instance method on each imported Group Instance). ClearSCADA checks whether any changes have been made to the Group Template between the Instance being exported and then imported. It then applies any changes that are found to the Group Instance.
- If a Group Instance is imported into a database and that import would result in a situation in which the Group Instance would be invalid:
- The imported Group Instance will be converted into a ‘normal’ Group
- Any database items in the Instance that are not supported by normal Groups (such as Abstract Items) will be deleted.
Situations in which a Group Instance would be invalid include:
- A Group Instance being imported into a database in which the Instance’s referenced Group Template does not exist
- A Group Instance being imported into its own Group Template
- A Group Instance being imported into another Group Instance, which itself references the same Group Template as the Group Instance that is being imported.
Should you make changes to a Group Template which has Group Instances that reference it, ClearSCADA will automatically propagate the changes to each of those Group Instances. With Group Templates that are referenced by fewer than 100 Group Instances, the time taken to propagate such changes should take only seconds, if noticeable at all. With large or complicated Group Template and Group Instance set-ups, there may be a noticeable period for which access to the database is prevented while the server propagates those changes. During this time ClearSCADA will block attempts to make certain changes locally to a Group Instance while the server is in the process of propagating any Group Template configuration changes to that Group Instance (see Activities that are Restricted when Configuration or Structure Changes are Pending). For a summary of the type of changes that ClearSCADA blocks until it has completed propagating Group Template changes to a Group Instance, see Configuration Changes and Structure Changes.
Further Information
Limitations if you Convert an Item in a Group Template (other than an Abstract Item).
Limitations that apply to Template expressions: see Template Expressions in the ClearSCADA Guide to Expressions.
Restrictions that apply to the names of parameters that you can use in Template expressions: see Template Parameters in the ClearSCADA Guide to Expressions.