Horner APG QX751 OCS - Manual (Page 60)

CH.10 MAN0890-02-EN
August 20, 2009 Page 60 of 96 ECN # 979
10.10 Screen
Saver
The QX751screen backlight life is typically 5 years when in continuous use. If the application does not
require interaction with the QX751for long periods of time, the backlight life can be extended by using the
screen saver function. When enabled through the system menu, the backlight is shut off (screen goes
black) after a specified time of no touch activity on the screen. When the screen saver shuts off the
backlight, any operator touch on the screen or function keys reactivates the backlight.
Note that when the screen saver is active (backlight shut off), any initial touch activity on the screen (or
function key) to reactivate the backlight is otherwise ignored by the QX751. Any additional touch activity
is also ignored by the QX751for approximately one second thereafter.
It is possible for the application to temporarily disable the screen saver by generating a positive transition
to %SR57.16 (coil only) at a rate faster than the screen saver timeout value. This may be desired while
waiting for alarm acknowledgement.
10.11 Screen
Brightness
The QX751provides a feature that allows screen dimming for night operation. To enable this feature, the
application must access and control system register %SR57 (Display Backlight Brightness). Screen
brightness is continuously variable by driving %SR57 through the range of 100 (full bright) to 0 (full off). It
is left to the screen designer on if and how to present a Screen Brightness control to the user.
Note that backlight life may be shorted when screen is dimmed or screen brightness is varied on a
repetitive basis.