Element scopes

Controller application tags and parameters

. Accessible to the entire controller application in which the tags and parameters are defined. All routines defined in a controller application can use the tags and parameters. The data in controller tags and parameters are available to every task, program, and routine in the controller application.

Controller application tags and parameters are not directly accessible to programs and routines in FactoryTalk Smart Objects. You must use parameter connections to pass tag and parameter values between the parameter connections.

Program defined in a controller application

. Tags and parameters are accessible exclusively by the routines within an individual program within

the same controller application. Program tags and parameters can have the same name in more than one program. This allows you to easily copy and reuse programs.

Program defined in a FactoryTalk Smart Object

. Tags and parameters are accessible by the routines defined in the program.

FactoryTalk Smart Object

instances can access the program tags and parameters to provide specific data values to instances of the

FactoryTalk Smart Object

.

Routine defined in a controller application

. Tags and parameters are accessible only to the routine. The JSR instruction passes data in and out of the parameters of the routine.

Routine defined in a FactoryTalk Smart Object

. Tags and parameters are accessible only to the routine.

FactoryTalk Smart Object

instances can access the routine tags and parameters to provide specific data values to

FactoryTalk Smart Object

instances.

Device tags

. Device tags are accessible to the entire project. For a device tag reference, an error message appears if a controller cannot access the device on the network.

Device tags are not directly accessible to programs and routines within FactoryTalk Smart Objects. You must use parameter connections to pass tag and parameter values between programs and routines.