Integration Overview


The primary integration task is to transfer field data to the server's database and then distribute that data back to the field and to the Web. Although Project Trailblazer has many field devices, the amount of data traveling back and forth consumes a small number of bytes. A variety of network communication protocols exist to connect the field devices to the Silverjack database. Each protocol offers different functionality, complexity, and target board file system usage. The engineers decided to keep the Project Trailblazer system integration as simple as possible. Their approach uses bash scripts wherever possible on the target boards and on the server. Figure 12.1 shows a software block diagram for the Project Trailblazer system integration.

Figure 12.1. Target board and Silverjack Server software components.



A block diagram shows a high-level representation of a system's major components, interfaces, and interconnections. It provides the big picture for a system.

The engineers' approach includes the following components:

  • bash scripting is used for field device control and for the Web server Common Gateway Interface (CGI).

  • Communication between field devices and the Operations Department uses the Hypertext Transfer Protocol (HTTP).

  • The nc program provides network communication for bash scripts.

  • A MySQL database stores all field data except for images, which are stored as files on the server.

  • The gnuplot program generates any required data plots on demand.

  • The Apache HTTP server distributes data to field devices and to the Web.

The remainder of this chapter describes how the Project Trailblazer engineers configured tbdev1 to act as the Silverjack server and provided system integration functionality for Project Trailblazer. This chapter focuses on three of the Project Trailblazer systems:

  • Temperature collection and distribution

  • Image collection and distribution

  • Guest lift access

The implementation of these three systems provides the integration foundation for all other Project Trailblazer systems.


    Embedded LinuxR. Hardware, Software, and Interfacing
    Embedded LinuxR. Hardware, Software, and Interfacing
    ISBN: N/A
    EAN: N/A
    Year: 2001
    Pages: 103 © 2008-2017.
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