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Hydraulic/Pneumatic Systems

Diagnostic Design

DSI’s approach to intelligent diagnostic design begins with developing a functional dependency model to fully describe the functions of a system. DSI’s eXpress tool allows the user to develop and utilize a functional dependency model to meet the goals of diagnostic engineering: improved available, reduced cost and increased safety. Effective development of system diagnostic involves a rigorous process of:


  1. Describing the system functionally through the development of a diagnostic dependency model
  2. Overlaying Failure Modes on top of functions to fully describe how the functions of the system components will fail.
  3. Add in cost, time and reliability to calculate Mean time and cost to repair and probability weighted detection and isolation statistics.
  4. Develop test definitions by defining what is learned diagnostically when a test is performed.
  5. Selecting and developing diagnostic strategies for troubleshooting of complex systems.
  6. Deployment of diagnostic solution using diagml to transfer the knowledge of the diagnostics to the deployed solutions.

Scalability of the System Engineering Process

One of the foremost challenges in large system design is keeping the engineering effort scalable. This is typically where engineering software becomes invaluable. As such, the question becomes, “How scalable is the software you are using?”

DSI has always recognized this problem as one of the principle design goals of the eXpress software. It is fairly easy to identify some key areas in which the system size becomes a concern:

  • Introducing additional lower-level data
  • Changing connectivity (model structure)
  • Changing testing and diagnostic approaches
  • Validating designs against the specification or other models

Solving the scalability problems associated with each of these provides the ability to run assessment reports so that optimization can occur.

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