Section 2 Installation Considerations
2.1
INTRODUCTION
The SAE5-35 Altitude Data System simplifies installations that include GPS, Terrain Aware-
ness Systems and other avionics that require RS232 altitude input information. The SAE5-35
provides standard Gillham Grey Code output on its 15 pin connector. Grey code is required
for interface to Mode C ATCRBS and Mode S transponders. Two independent RS232
outputs are provided on the nine pin connector. The SAE5-35 also incorporates
SANDIA
aerospace’s
exclusive Altitude In-flight Monitoring (AIM) feature that advises pilots if they
deviate from their selected altitude by more than one hundred feet. The AIM feature can be
installed by purchasing
SANDIA aerospace’s
optional annunciator/switch assembly, P/N
305217-00. Or the installer can supply his own switch and annunciator assembly(s). The
main 15 pin connector follows the standard encoder interconnect used by many manufactur-
ers. By following this convention, upgrading to the SAE5-35 is made easier. If another
manufacturers encoder is being replaced, it is important to check the wiring information
before plugging the existing connector into the SAE5-35. Both the Grey Code output and
each of the RS232 outputs have separate drivers. This ensures that a load on one line does
not load the other. Additionally, the RS232 output is available even if the enable line on the
Grey Code has not been enabled by the transponder.
The SAE5-35 does not require warm up unless the outside temperature is below 20 degrees
C. When warm up time is required, the internal heater is capable of warming the SAE5-35
from -20 degrees C to operating temperature in less than two minutes.
2.2
MOUNTING CONSIDERATIONS
The SAE5-35 can be mounted in any axis and either inside or outside the pressure vessel.
Mounting should allow for as short a pressure line as possible from the encoder to the altim-
eter. Be sure to allow an ample service loop on the cable to allow for calibration of the
SAE5-35
CAUTION: DO NOT mount the SAE5-35 in
the direct airstream or near either the hot or
cold air ducts.
2.3
COOLING
The SAE5-35 does not require external cooling.
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