Sanden SN3500, Installation Manual

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General Information
82005-IM-K Sandel SN3500 Installation Manual Page 1-4

Quadrature stepper motor drive input from a Bendix/King KG 102 series
DG with compass valid output and flux gate connected directly to SN3500
(internal slaving).

3-wire ARINC 407 synchro DG with or without gyro valid output and
fluxgate. (internal slaving)

3-wire ARINC 407 synchro remote or panel mounted DG self-slaved with
or without gyro valid output. (SN3500 unslaved)

ARINC 429 Heading Input from AHRS. Sandel monitors for Label 320,
Magnetic Heading Data and Label 270 System Status (SN3500 unslaved)
Internal slaving requires connection of the flux gate excitation to the SN3500 flux gate
reference input P2-24. This input is used only to demodulate the flux gate signals.
DG’s with XYZ bootstrap outputs require the master 400Hz inverter to be connected
to the SN3500 400Hz reference input on P1-16. This input is used to lock all 400Hz
inputs on P1 and 400Hz outputs in the SN3500. This input presents no loading to the
source.
Follow the information on the installation drawings, and plan to set up the appropriate
compass selections on the compass system maintenance page.
Internal slaving does not require the use of an external slaving accessory. Compass
calibration is performed using the SN3500 Compass maintenance page. The
SN3500 will provide standby heading operation from the flux gate alone in the event
of directional gyro (DG) failure.
The SN3500 has a 3-wire ARINC 407 synchro bootstrap compass output if required
which is capable of driving electronic loads.
1.4.2 Autopilot Switching
The SN3500 has low level deviation and flag outputs intended to drive an autopilot.
These outputs feed from the pilot selected navigation source. These outputs may
eliminate the need for an external autopilot switching relay.
However if an external switching relay is used (for instance for compatibility with an
existing installation) the SN3500 has protected Open Drain relay output discretes
intended to drive external switching relays. These outputs have 250ma maximum
current and pull to within 1 ohm of ground.
NAV1 selection is the default selection and no relay driver output discrete is available.
The NAV2, GPS-1, or GPS-2 outputs can be used to operate a switching relay for
each source, allowing the pilot to control the NAV source selection from the front
panel of the SN3500. This is referred to as “master” mode and it is the preferred
mode of installation. In this configuration an additional remote switch/annunciator
panel for a GPS receiver is not required.
In the event the aircraft has an existing GPS switch/annunciator panel or it is desired
that one be installed, the “GPS SELECTED-” input on the SN3500 is used to remote