Considerations for External LEVEL Button
in SkyView systems with multiple SkyView displays
Prior revisions of the SkyView System Installation Guide recommended that in
SkyView systems with multiple displays, for redundancy the External LEVEL Button
should be connected to all SkyView displays in parallel. The following
recommendations supersede that earlier guidance.
Do not connect CONTACT 1 / LEVEL BUTTON inputs of multiple SkyView displays
directly together. If you do so, when one display is powered off, it will cause
displays that are powered on to see the CONTACT 1 / LEVEL BUTTON input as
being pushed (the display powered off will “ground” the input). This could cause
the unintentional activation of LEVEL mode or could prevent the External Level
Button from operating.
Installation options installing the External LEVEL Button on systems with multiple
SkyView displays:
1. Connect the External LEVEL Button to only one display. The External LEVEL
Button will operate for all displays in the SkyView system as long as the
display the External LEVEL Button is wired to is powered on and operating
normally. As a non-flight-critical function, the loss of the External LEVEL
Button in some display failures may be acceptable for your installation. Use
of the LEVEL function via the SkyView soft keys via any operating SkyView
display is still possible, as well as pushing the LEVEL button on the
(optional) SV-AP-PANEL.
2. Install a diode for each individual display’s connection to the External
LEVEL button. The diode should be installed with the cathode end (painted
band on the diode) oriented towards the External LEVEL button, and
should be installed in-line with the contact wire between the SkyView
display and the External LEVEL button. One diode is needed per display.
Any diode will work for this application. An example diode is the very
common 1N914, available from Radio Shack (P/N 276-1122). With a diode
installed for each display, the External LEVEL Button will work correctly
with any combination of displays powered on and powered off.
3. Use a multi-pole pushbutton (momentary, normally open / push to close)
for the External LEVEL Button. With this option, run each display's
connection to a different pole on the pushbutton. With the multi-pole
pushbutton installed, the External LEVEL Button will work correctly with
any combination of displays powered on and powered off.
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