Sandel
Avionics
SN3308 Navigation Display
Installation Manual
90106-IM-G(4) Installation Manual W SIG.doc
Page 32
P1-6: Flux Gate Y Input
P1-24: Flux Gate Z Input
P1-25: Flux Gate X Input
Connections to these pins are made directly from the heading system flux gate
if internal slaving is selected on the compass maintenance page. If a
Bendix/King KI-525 PNI or Rockwell/Collins 331A-3( ) HSI is being removed,
the respective slaving accessory, should be bypassed. See the installation
drawings for details. 24 AWG twisted shielded triple conductor is
recommended for these signals.
P1-7: Flux Gate Excitation Input
This connection is made to the 400 Hz AC flux gate excitation source voltage.
a 24 AWG shielded wire is recommended for this function. Note: the phase of
this excitation voltage is not required to be the same as that supplied to the
Primary AC Excitation input on P2-4, if used.
P1-26: Display Brightness
Input from the pilots display brightness control. 0Vdc – Acft. Power
P1-8: VHF Nav-2 ILS Energize Input
P1-27: VHF Nav-1 ILS Energize Input
These pins control the enabling of the Glideslope pointer. They are not related
to the bearing pointer operation.
These signals also control the ILS Lockout logic so the SN3308 can sense
when a GPS receiver is inappropriately selected as the primary nav source
when ILS Lockout is not disabled on the NAV maintenance page.
Connections to these pins are from the respective VHF navigation receiver
and optionally by the GPS receiver. The logic level of these inputs are
selected on the Nav maintenance page, and are normally active-low.
NOTE: If ILS Lockout is disabled, NAV1/GPS1 vertical guidance is enabled
by P1-27 and NAV2/GPS2 vertical guidance is enabled by P1-8.
NOTE: The ILS Energize inputs are pulled up to one-half aircraft power. In 12
volt aircraft this will make logic high 6Vdc. This many not be satisfactory as
the non-energized state of an associated nav converter or indicator. To
increase the inactive high voltage, a 4.7K pullup resistor to aircraft power may
be used externally to the SN3308 for 12v aircraft.
P1-9: Directional Gyro Valid Input
Connect to the (DG) valid output if available. Selection of the logic level of this
pin is in the Compass maintenance page.
P1-10: VHF Nav 2 VOR Composite Input
P1-29: VHF Nav 1 VOR Composite Input
