Unity Pro XL V6.0 (currently referred to as Control Expert) introduced MBP_MSTR FC 16. This function code allows the user to change the log in status of an ethernet port. In cases where you are unable to connect to a Quantum PLC because the ethernet port is seen as " Already logged in" this FC will prove useful. MBP_MSTR FC 16 will allow you to change the port status to "logged off" and allow the Unity user to log in.
This would be preferable to using FC 10 (Reset Option module) or performing a power cycle of the PLC.
There are minimum requirements that the user must meet in order to use MBP_MSTR FC 16. 140NOE77101 minimum firmware version....4.9
140NOE77111 minimum firmware version....5.0
140CPU65x xx minimum coprocessor firmware version 3.5