A Join from a subordinate JACE station is one of two ways to perform an export tag Join. The other way is to Join from the Supervisor (providing that the Supervisor already has a working NiagaraStation entry for this JACE in its NiagaraNetwork).
However, a Join from the JACE is possible even in the scenario where the Supervisor is currently “unaware” of this JACE. Additionally, a Join from a JACE provides a built-in “job log”, as described.
To Join from the subordinate (JACE) station
-
In Workbench, open the JACE station.
-
In the Nav tree, expand its Config Drivers/NiagaraNetwork
container, to reveal the child 
SubordinateExportTagNetworkExt and Supervisor) 
or 
station.
-
Double-click this
network extension for its Join Profile Manager view
-
In the Join Profile Manager, click the Supervisor station to select it, then click the
button at the bottom of the view.
As shown in Figure 7, the Join executes and ends with a popup Job Log that lists all operations performed in the Join. This lets you review all changes, and if desired, save (export) to a text file. In case of any errors encountered in the Join, the job log can help locate specific export tag problems.
In addition, a brief Job popup “Subordinate Join” notification appears near your PC’s system tray area.
Starting in AX-3.7, “Fox SSL” may be used in connections between the JACE stations and the Supervisor, depending on configuration.
In this case, note that initial Join attempts may fail due to “non-approved certificate host name validation”. If so, you
will see the appropriate errors in a Join’s job log. You must manually approve certificates between the client and server
before Joins can succeed. Typically you do this from the “Allowed Hosts” tab of the “Certificate Management” view (on platform
service: CertManagerService) in the stations. For complete details on AX-3.7 and later SSL, refer to the NiagaraAX SSL Connectivity Guide.
You can also issue a Join in the subordinate station as a “right-click action” on the 
SubordinateExportTagNetworkExt, or on the Supervisor station as listed in the Join Profile Manager view. However, if you invoke the Join using either of
those methods, you do not see the “automatic” popup Job Log dialog with all the details from the Join, as shown in Figure 7.
In AX-3.7u1, when issuing a Join from a subordinate JACE station, and that station does not already exist in the Supervisor,
the “Default Subordinate User Password” property must be configured with a valid password for the selected “Default Subordinate
User”. If no valid user and password has been entered the Join will fail due to authentication errors. For further details,
see Editing the Join Profile.
For related details about a Join (in general) as well as a Join from a JACE, refer to About a Join and Join process from subordinate.