Each function should be linked to a single service type or organizational element via a connection of type carries out or supports.
This means that no function must have more than one of the following relationships in the model or in an assigned function allocation diagram:
An object of type Service type has a single connection of type supports (CT_CAN_SUPP_1) to a function.
An object of type Position (OT_POS) has a single connection of type carries out (CT_EXEC_1) to a function.
An object of type Role (OT_PERS_TYPE) has a single connection of type carries out (CT_EXEC_2) to a function.
An object of type Organizational unit (OT_ORG_UNIT) has a single connection of type carries out (CT_EXEC_1) to a function.
An object of type Group (OT_GRP) has a single connection of type carries out (CT_EXEC_1) to a function.
An object of type Organizational unit (OT_ORG_UNIT) has a single connection of type carries out (CT_EXEC_2) to a function.
An object of type Application system type (OT_APPL_SYS_TYPE) has a single connection of type supports (CT_CAN_SUPP_1) to a function.
If no service type or organizational element is modeled, a warning message occurs when a semantic check is performed for the model. If more than one service type or organizational element is modeled, an error message occurs and the model can no longer be transformed. First, it is checked whether or not there is more than one service type or organizational element at definition level. If not, then it is checked whether or not there is more than one service type or organizational element on occurrence level.
It is irrelevant whether these connections have an occurrence in the model to be transformed; all connections of the functions in the database are checked. If an error occurs due to incorrect connections, a reorganization of the database may resolve the error.
In contrast to an EPC, BPMN distinguishes between manual tasks, semi-automated tasks (so-called user tasks), and automated process steps (so-called service tasks). Assigning service type or organizational unit to a process function in the EPC enables the transformation into the corresponding task type in the BPMN diagram. The task type is represented with a symbol in the task object itself.