Sandel ST3400H HeliTAWS, Installation Manual

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3 INTERFACE FUNCTIONS
3.1 Power
The primary power is 28 volt dc on J-2 and is supplied from the aircraft avionics buss through
a circuit breaker. Ground is provided on J-2 and should be attached to an approved airframe
ground.
A 26 volt 400Hz excitation input is available at J-16. It is only used in the case of an XYZ
heading source. If the installation of the ST3400 does not use an XYZ (ARINC407) signal
source, the inverter input is not required and should be grounded.
3.2 GPS/FMS
A GPS position input is required. The port is configurable in the Maintenance Menu pages for
High or Low speed ARINC and RS232. A list of supported labels is listed in section 8.8 .
A separate GPS flight plan input is normally connected but is optional.
In the case where all information is coming from the same 429 source, the single receiver is
fed to both inputs.
Note : In the case of the Garmin GNS series, the position input is connected to the
receiver’s RS232 output, and the Flight plan data is connected to the receiver’s GAMA
ARINC 429 output.
3.3 Heading System
A Heading input is not required. However, without a heading system the terrain display will
be removed at low groundspeeds. When the heading input is present the terrain display
remains on the screen even during hover operations. It is highly recommended.
When in maintenance mode, with no heading system and track invalid, unit displays North
Up.
3.4 Radar Altimeter
The ST3400H has provisions for a Radar Altimeter input. Radar Altimeter input may be from
an ARINC 429 or DC analog sources. The Radar Altimeter input is used to obtain height
above terrain for GPWS alerting and for altitude callouts.
The Radar altimeter always produces a single ‘300’ or ‘100’ mandatory audio callout,
depending on NORM/LOW sensitivity selected by the pilot. When in HIGH-SENS, a ‘400’
mandatory audio callout will be produced. Optionally the installer may enable any or all of the
following additional audio callouts:
300’, 200’, 100’, 50’, 40’, 30’, 20’, 10’
These callouts are a great safety feature and their use is encouraged.
82046-IM-K ST3400H INSTALLATION MANUAL Page 3-1