SAE AIR4013

Description / Abstract: This SAE Aerospace information report (AIR) will examine network aspects of open and shorted stubs, line reflections and bus loading due to network changes. Single network level is assumed, that is, no carriage store hierarchical levels. However, two passive network coupling variants called "branched bus" and Branches stub" will be introduced that possibly could be used in a stores management network.

This report assumes familiarity with MIL-STD-1553B.

Purpose:

This document summarizes the results of hardware tests on simulated weapon data bus networks utilizing MIL-STD-1760.

Unique to this application is the fact that the network is reconfigurable by connecting together mission dependent MIL-STD-1553B store remote terminals (RT)s at artificial network breakpoints. Future, during normal data bus operation the weapon RTs are physically removed from the network. That is, in-flight weapon separation from aircraft results in "open stubs" on the bus network. All this gives rise to changing network conditions, stubs exposed to harsh environments (such as during rocket motor firing) noise interference, interoperable store requirements for US/NATO military service and controversy about the effect of "open stubs" on bus performance