Sandia Aerospace SA 3NVG - Manual (Page 11)

2.2 Mounting Considerations
The MARC70 family of interface modules and their associated mounting enclosures can
be mounted in any attitude and either inside or outside the pressure vessel. Each card is
installed in the desired mounting enclosure by inserting it into a vacant location and secur-
ing it with the two stainless steel fasteners attached to the modules front plate. The interface
modules can only be inserted and secured in one direction. While the modules are relatively
easy to install and remove in the enclosures, considerations should be given to service access.
At least six inches of clearance should be provided at the front of the enclosures for removal
and reinsertion of MARC70 modules It is also recommended that enough cable be supplied
so that the interface modules can be inserted and removed with the cable harness and connec-
tor attached to the module. This will aid in any calibration that may be required and will also
simplify attaching the connector to the interface module.
. 2.3 Cooling
Cooling for the MARC70 is not required. However if several higher current modules, such
as annunciator drivers are installed, adequate space should be allowed for convection cool-
ing. The SA 3NVG must be mounted in the right most slot of the SRU-5-01, PN 305018-
01and secured with two screws supplied with the unit.
Section 3 Installation Procedures
3.1 General
Each MARC70 module is supplied with a mating connector, crimp style pins and an indenti-
fication tag. The identification tag is to be placed on the top of the enclosure directly over the
slot in which the module is installed. The enclosures are supplied with enough blank plates
and screws to cover any unused slots. Extra blank plates and screws can be discarded or
retained in case a module is ever removed.
3.2 Mounting Instructions
The SRU 1 is attached to an aircraft structure by using four #10-32 screws as shown in the
outline drawing.
Section 2 Installation
2.1 Introduction
The MARC70 family of enclosures and interface modules has been designed to simplify and
standardize installation of avionics systems. SANDIA aerospace supplies each mounting
enclosure and interface module separately. The installer can mix and match the modules in
the enclosures to meet specific requirements. Except for the SR 34, SR 54 and SR 64, each
of the module’s connectors is keyed to prevent inadvertently attaching the wrong connector.
It is important that the installer insert the supplied plug in the proper location in the mating
connector for the keying to be complete.
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