Chapter 1. Basics of avionics systems

1.6. Integrated modular avionics

The use of electronic devices division avionics LRU to stir and allow to create systems of any complexity, but at present LRU does not correspond to needs of a modern building systems. Each system is placed on the PC at least one LRU. Each LRU - is a specific computer system that requires a certain operating system and related software to function. Increasing the number of systems and improve their functionality paved to review the concept of building LRU

The integrated modular avionics (IMA) - a fundamentally new architecture building avionics systems based on a very tight integration of various systems and functions blocks.

Integrated modular avionics provides integration to block and functional levels.

Integration at block level in Integrated modular avionics concept

Involves the use of new avionics modules (LRM), with even smaller dimensions compared to the LRU. Avionics modules are placed on a special rack for LRM (Integrated Rack - IR or Cabinet) close to each other (Fig. 13). Every place reserved for LRM, equipped with IR standardized mechanical and electrical connections, allowing manufacturers to create different interchangeable system. IR - is a universal rack for LRM, because it can be installed LRM any size. In addition, there is no need for placement in each block of the power supply, as all modern microprocessor devices require a uniform supply voltage. So enough is to use a voltage conversion of the block for all LRM, placed on one rack. Deprivation of power supply in each of the blocks can not only reduce the overall weight, but also increases the flexibility of the system. LRM modules are divided into functional module power supply, computer, etc. interaction module.

Fig. 13. Rack for LRM

Integration at the functional level. Modern computer systems can perform a large number of computing functions that allows to combine different systems in new performing the functions of many systems. In addition, a module computer system can perform calculations for the other; This allows more efficient use of hardware resources by distributing computing operations between LRM.

Advantages of IMA:

  • A significant reduced dimensions of of avionics and the total mass;
  • More economical consumption of energy;
  • Allocation of resources (LRM one power supply for the entire rack);
  • Standardized dimensions of blocks (length and height are the same), allowing not tied to a particular place on the shelf;
  • IMA concept more reliable than using separate LRU.

The concept of IMA could be used to build different types of avionics systems and ensure high reliability. The use of IMA is the best solution to accommodate a large number of systems on a single PC. In addition, IMA concept aimed at rapid modernization of used equipment, which is very important in the rapid development of microprocessor technology and functionality systems.

During the construction of avionics for the concept IMA provides for the grouping of certain functions and related modules in one IR (eg, equipment, communications, navigation, surveillance, engine control and so on. Al.) (Fig. 14).

Each IR contains voltage converter from the mains PC board to the desired level, network equipment to transmit and receive data over the channel information exchange equipment input - output for interaction with a remote control and display system and a corresponding number of LRM. All IR combined with a network equipment into a global network of information exchange between LRM PC.

Fig. 14. The concept of IMA

Certain digital sensors can also be connected to the global information exchange channel. However, to obtain and analyze information from sensors using specialized data hubs (Signal Data Concentrator, SDC), which are similar in structure to the IR (Fig. 15). The main objective of SDC is to collect information from certain sensors, process measurements on special evaluative algorithms and parameters estimated delivery through global channel information exchange systems that need them.

Fig. 15. Internal structure of SDC
AVIONICS training course materials represented only in demonstrative mode. If it useful, all grammar mistakes will be corrected and more documents will be added. Let me know if you interest in avionics.
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(29th of April, 2016)
I have taught and worked on commercial avionics systems, and I am interviewing for an Avionics Instructor position this month for a major airline. My presentation is on B777 AIMS, and I am researching IMA, CPMs and I/O Modules to talk about how the system works.
(4th of September, 2015)
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Avionics training in details by
Ostroumov IvanOSTROUMOV Ivan, PhD
Associate Professor, www.ostroumov.sciary.com