MIL-HDBK-244A 6 apr 90.pdf

MIL-HDBK-244A
systems allows chanqes to aircraft o~eration by chanqinq the data distributed
o; the multiplexed ~iring channels without cha~ging ~he-hardware associated
with the channels.
5.1.3.4 Test circuits. New systems must be designed with extensive
Built-in-Test (BIT) capability to reduce the amount of external ground support
required to support the checkout and maintenance of the weapon system.
Effective implementationof this BIT capability requires active involvement
during all phase of the system development process by aircraft, suspension
equipment, store, and SMS designers. The exchange of BIT commands and status
reporting across the aircraft/store interface will be requiredand therefore
must be considered as part of aircraft/store compatibility. Tests of bridge
wires may include applying low level test currents to the bridge wire provided
that the test current does not exceed 50 MA or 10% of the minimum no
fire current of the electro-explosivedevice, whichever is less.
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5.1.3.5 Electricalconnectors. Connectors must be designed to
prevent accidental shortingof contacts during mating of the plug and
receptacle. The connector must contain positive mating.features to prevent
any possibility of mismatching. It should contain peripheral grounding
fingersthat connect the two mating halves of the connector be-fow+pin and
socket contacts make connection. The connector should also contain provisions
for terminating shield braid for EMI protection. The connector mating
halves on the aircraft, store and suspension equipment sides of the interface
should have socket type contacts and electrical adapter harness connector
mating halves should contain pin type contacts. Refer to MIL-STD-1760 for
connector requirements. The aircraft SMS should be designed to ensure that
the store connectors are not powered until an indication that the interface
mated condition exists. Furthermore,the aircraft SMS,design should ensure
that.power is removed from the interface before a store separation at that
interface to avoid powerarcing and associated equipment damage during
disconnect of a powered connector.
5.1.3.6 Pin function assignments. The approach to pin function
assignments must first include a pin study to segregate signals into
categories whichrelatethe electrical functions and provide the maximum
safety and electromagneticcompatibility. The characteristicsof every signal
in the aircraft/weapon interface should be defined as follows:
(a) Function name.
(b) Signal type - analog, discrete, pulse train, fire
(single end or differential).
(c) Signal voltage - AC, DC.
(d) AC’signal - volts, amperes, power factor, and phase
relationship.
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