Sandia Aerospace SA 3NVG - Manual (Page 5)

Section 1 General Description
1.1 Introduction
This manual describes the installation of the SANDIA aerospace MARC70 line of interface mod-
ules. It is intended for use by FAA certified repair stations to install the MARC70 modules. It
includes both the mechanical and electrical installation information for all MARC70 components,
including the individual modules and enclosures. Where applicable, alignment and checkout proce-
dures are included. In many instances, such as with switching relays, the checkout procedure will be
performed as part of the major system installation check out and no specific check out procedure is
provided for in this manual. In any case, the installer should insure that all functions are operating
according to their intended purpose in their particular installation.
1.1.1 Interface Modules
All interface modules have the same mechanical dimensions and are inserted into the card enclosures
in the same manner. An identification tag accompanies each interface module which should be at-
tached to the card enclosure directly above the interface module to identify it. Each interface module
connectors, except the SR 34, SR 54 and SR 64, is keyed to prevent the inadvertent installation of
the connector into the wrong module. Keying of the module has been accomplished at the factory by
the removal of one of the pins on the module’s connector. The installing agency MUST insert a key-
ing plug into the appropriate pin location on the harness connector to complete the keying process.
Each MARC70 interface module is FAA-PMA approved and has been tested to meet the require-
ments necessary to allow it to be mounted outside the aircraft’s pressure vessel. Each interface mod-
ule has passed the vibration requirements for helicopter installations. See section 1-2 for complete
technical specification on each of the MARC70 modules.
1.1.2 Card Enclosures
Several different card enclosures are available depending on the application and installation space
available. If an enclosure is not filled, the unused card slots are covered with blank panels. These
extra card slots can be used in future installations or system upgrades, eliminating the need to re-
engineer the mechanical installation. Interface modules are secured to the enclosures with captive
stainless steel screws. In installations where the enclosure is difficult to reach, the harness connector
can be attached first then the module inserted into the appropriate card slot and secured with the cap-
tive hold down screws.
1.1.3 SRU-1
The SRU 1 is a single card enclosure which accepts any MARC70 interface module. The SRU 1 is
ideally suited for installations where only one MARC70 card is required or where there is limited
real estate for mounting the larger enclosures. The SRU 1 can be mounted in any axis and either
inside or outside the pressure vessel.
1.1.4 SRU 5
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