Class relations determine which classes can be related to each other, which in turn determines the objects and design parts that another object can be connected to. Class relations, in a large part, determine the from/to navigational structure of a design object and can be configured to display the countless variations that may exist within a plant. For example, relations for the MOTOR class can be set up to show each motor's attached cables (Leaving and Arriving), the room the motor is located in (e.g., Location: 10), and its junction box connection (e.g., 10-JB-001).
Class relations simplify the registration process by limiting the number of relations that appear in the List of Values, which ensures that only appropriate relations can be made. For example, when registering a transmitter, the only possible functional parent relation to select from would be an instrument loop. Class relations are defined for both design parts and object classes.
The Class Relations tab of the Class page is used to configure relations. All relations are configured on a per-class basis; that is, all pumps in the PUMP Class share the same relations. Customized relations can be created using the default relations as templates. Ordinarily, classes are created and their relations are configured afterwards. However, the required class relations may influence a class more than the class's technical data or ID designation.
Objects are the focal point for the main relations to other objects, design parts and documents, among others. Each of the relations below can be applied bi-directionally. The object classes listed in the table below are examples; they illustrate how an actual relation might read.
| N | An Object of Class | Class Relation Description | Object(s) of Class | N |
| 1 | CIRCUIT | can have free functional children | TRANSMITTER | n |
| n | TRANSMITTER | can have a free functional parent | CIRCUIT | 1 |
| 1 | BUILDING | can have free locational children | ROOM | n |
| n | ROOM | can have a free locational parent | BUILDING | 1 |
| 1 | PS_DATA | can be process data for | VALVE | n |
| n | VALVE | can have process data | PS_DATA | 1 |
| 1 | CIRCUIT | can use signals from | SIGNAL | n |
| n | SIGNAL | can be a signal for | CIRCUITS | 1 |
| 1 | MCC (Motor Control Central) | can have leaving | CABLE | n |
| n | CABLE | can leave from | MCC | 1 |
| 1 | MOTOR | can have arriving | CABLE | n |
| n | CABLE | can arrive at | MOTOR | 1 |
Relations are bi-directional - defining the relation in one direction also defines it in the other direction. The following object relations can be modified as necessary. The object classes are examples used to illustrate the connection types.
| N | An Object of Class | Class Relation Description | Object(s) of Class | N |
| 1 | MCC_COMPARTMENT | can supply | MOTOR | 1 |
| 1 | MOTOR | can be supplied by | MCC_COMPARTMENT | 1 |
| n | RELIEF_VALVE | can affect | PRESSURE_VESSEL | 1 |
| 1 | PRESSURE_VESSEL | can be affected by | RELIEF_VALVE | n |
| n | SIGNAL | can assign | CHANNEL | 1 |
| 1 | CHANNEL | can be assigned to | SIGNAL | n |
| 1 | MCC | can preliminarily supply | MOTOR | n |
| n | MOTOR | can preliminarily be supplied by | MCC | 1 |
| 1 | MOTOR | can drive | PUMP | 1 |
| 1 | PUMP | can be driven by | MOTOR | 1 |
| n | CIRCUIT | can preliminarily assign | DCS | 1 |
| 1 | DCS | can preliminarily be assigned by | CIRCUIT | n |
| n | TRANSMITTER | can be located next to | PIPE | 1 |
| 1 | PIPE | can have closely located | TRANSMITTER | n |
| 1 | MCC_COMPARTMENT | can supply as spare | MOTOR | 1 |
| 1 | MOTOR | can be supplied by spare | MCC_COMPARTMENT | 1 |
| 1 | MCC | can supply as spare | MOTOR | n |
| n | MOTOR | can be supplied by spare | MCC | 1 |
| 1 | PIPE SYSTEM | can have pipe parts | VALVE BALL | n |
| n | VALVE BALL | can have a pipe parent | PIPE SYSTEM | 1 |
| n | PUMP | can have an additional part | IMPELLER | n |
There are three, bi-directional default design part connection types that can be applied. Each design parts class listed below is an example: they exist only to illustrate the connection type.
| N | A Design Part of Class | Class Relation Description | Object(s) of Class | N |
| 1 | MOTOR | can be a design part for | MOTOR | n |
| n | IMPELLER | can be an additional part for | PUMP | n |
| A Design Part of Class | Design Parts of Class | |||
| n | PUMP | can consist of | IMPELLER | n |
| n | IMPELLER | can belong to | PUMP | n |
The definition of design objects and parts related to an object on Design Object pages is governed by the object relations defined for a particular class. When connecting the relation to the object, each relation may receive just one value. One or more of the following relations may be added: