Siemens SIMATIC NET SCALANCE W774-1 Operating Instructions Manual page 35

Function
The device supports the following modes of operation:
• Without PLUG
The device saves the configuration data in the internal memory. This mode is active
when no PLUG is inserted.
• With PLUG
If an unwritten PLUG (factory status or deleted with Clean function) is used, the local
configuration already existing on the device is automatically stored on the inserted
PLUG. If the PLUG contains a license, additional functions are also enabled.
A device with a written and accepted PLUG ("ACCEPTED" status) uses the
configuration data of the PLUG automatically when it starts up. Acceptance is
possible only when the data was written by a compatible device type.
One exception to this can be the IP configuration if it is set using DHCP and the
DHCP server has not been reconfigured accordingly. Reconfiguration is necessary if
you use functions based on MAC addresses.
The configuration stored on the PLUG is displayed over the user interfaces.
If changes are made to the configuration, the device stores the configuration directly
on the PLUG, if this is in the "ACCEPTED" status. The internal memory is neither read
nor written.
Response to errors
Inserting a PLUG that does not contain the configuration of a compatible device type,
accidentally removing the PLUG/KEY-PLUG or general malfunctions of the PLUG are
signaled by the diagnostics mechanisms of the device (LEDs, Web-Based Management
(WBM), SNMP, Command Line Interface (CLI) and PROFINET diagnostics). The user
then has the choice of either removing the PLUG again or selecting the option to
reformat the PLUG.
Note
Incompatibility with previous versions with PLUG inserted
During the installation of a previous version of the firmware, the configuration data can
be lost. In this case, the device starts up with the factory settings after the firmware has
been installed. In this situation, if a PLUG is inserted in the device, following the restart,
this has the status "NOT ACCEPTED" since the PLUG still has the configuration data of
the previous more up-to-date firmware. This allows you to return to the previous, more
up-to-date firmware without any loss of configuration data. If the original configuration
on the PLUG is no longer required, the PLUG can be deleted or rewritten manually using
"System > PLUG".
SCALANCE W774-1 / W734-1
Operating Instructions, 03/2022, C79000-G8976-C325-15
Description of the device
4.7 PLUG
35