Raymarine e7 User Reference page 286

Shared brightness
You can set up shared brightness groups (or "zones") to adjust the
brightness on multiple units simultaneously.
The following units are compatible with shared brightness groups:
• e7 multifunction displays
• i70 instruments
• p70 / p70R pilot controllers
• ST70
• ST70+
Once compatible units are added to a shared brightness group,
any brightness adjustment made to any of the units in the group
is also reflected in all other units in that group. An on-screen
single brightness control is available for controlling any units in the
brightness group:
286
Multiple brightness groups can be configured. This can reflect
the physical location of the units on your vessel if required. For
example, the units at your helm can be set to one group, and the
units on the flybridge can be set to a different group. In this example,
any brightness adjustments made to a unit at the helm would be
automatically reflected in the other units at the helm.
The shared brightness function requires the following:
• All units must be compatible with the shared brightness function
(see list of compatible units above).
• Before a unit can respond to a shared brightness adjustment it
must be assigned to the relevant Brightness Group.
• A single unit can only belong to one brightness group at any one
time.
• The Share brightness setting must be set to ON for all units in
the brightness group.
• When setting up a brightness group an initial Sync brightness
operation must be performed, with all the displays in that group
powered on, to synchronize the display brightness of all units in
the group.
Setting-up shared brightness
With the homescreen displayed:
1. Select Customize.
2. Select Display Preferences.
3. Select Shared Brightness.
4. Select the ON option for the Shared brightness menu item.
5. Select Brightness Group.
6. Select an appropriate brightness group.
7. Repeat the process for the other displays you want in the
brightness group. If the display is not a multifunction display,
e7 / e7D — User reference