For the properties comparison of projects using "Alternative identification", objects are not identified according to their internal object ID, but according to candidate keys (certain identifying properties). This is handy for automatically generated projects because internal object IDs are reallocated every time.
A candidate key is a minimal quantity of properties that uniquely identifies an object. The identifying properties are preset by EPLAN.
In projects selected for comparison, two objects to be compared to each other are found as follows:
- First, the pages are assigned. The full page name and page type are used for identification.
- First, the objects are searched for on the assigned page.
- The objects with the same identifying name are assigned. (In case of connections, the identifying name of the source and target must match.)
- Depending on the object type, the required properties are compared.
- If the assignment is then not yet unique, the optional properties are compared.
- As a last option, the program attempts to assign the objects on the basis of their graphical position on the page.
- If no other object is found for an object with which to compare it, it will be highlighted as "added" for the purposes of the comparison.
Required and optional properties
For the different object types, the following properties are required or optional for identification:
Functions
Required:
- Representation type (ID 20121)
- Function definition (ID 20188)
- Connection point designations (all) (ID 20038)
- Additional identifying name element (ID 20032)
- Additional identifying name element for multiple terminals (internal property, ID 20233).
3D part placements
Required:
- Representation type (ID 20121)
- Function definition (ID 20188)
- Connection point designations (all) (ID 20038)
- Legend item (ID 20450).
Interruption points
Required:
- Representation type (ID 20121).
Optional:
- Page name (ID 19022).
Connections
Required:
- Representation type (ID 20121)
- Terminal / Pin designation (ID 20030)
- Plug designation (automatic) (ID 20431)
- Function: Connection point designation (ID 20022).
Optional:
- Source: Target number (ID 31023)
- Target: Target number (ID 31024)
- Page name (ID 19022).
Potentials
Required:
- Name of potential (ID 33000).
See also