Proposed Blueprints for Technical Standards
In the world of software and engineering, a clean schematic is a prized asset for its clarity and ease of understanding. One individual who has been pondering the elements that make a clean schematic is Graham Sutherland.
While the software industry follows established standards such as MISRA, CERT, and various NASA standards, Sutherland acknowledges that some rules for a clean schematic are subjective. For instance, the use of wires going horizontally or vertically is generally a rule, but exceptions may be made, as Sutherland suggests that in the case of crossing two parallel wires, diagonal lines could be used instead.
Sutherland also emphasizes the importance of using enough space, adding labels, and avoiding quirky angles for a clean schematic. However, he acknowledges that these rules are more guidelines than hard rules. In some situations, such as when in a hurry to get to a simulation, Sutherland has admitted to intentionally violating some rules.
The quote, "You can do anything you can get away with, but nobody has ever gotten away with much," by Flannery O'Connor can also be applied to the creation of clean schematics. This sentiment underscores the need to balance between following rules and being flexible when necessary.
In the aerospace industry, NASA serves as a beacon for clean and effective schematic design. While NASA does not publish one comprehensive schematic design standard publicly specifying exact drawing rules, their requirements for aerospace electronics design integrate strict verification flows, compliance with aerospace quality management standards, and the use of standardized symbols and schematic practices.
Two key standards that control the quality, connectivity, and reliability of aerospace electrical schematics and assemblies are NASA-STD-8739.1 and NASA EEE-INST-002. The former addresses electrical connections, soldering processes, solder joint quality, and inspection methods tailored for aerospace applications, ensuring that electrical assemblies, including PCBs, function reliably under extreme space environment stresses. The latter focuses on verifying connectivity robustness, component screening, qualification, and derating to ensure system cohesion, compatibility, and high reliability in harsh space conditions.
Despite these standards, there are exceptions where hardware is beautifully documented, and poorly documented software is prevalent. This disparity highlights the need for continued efforts in improving software schematics to match the high standards set by the aerospace industry.
Even with these guidelines, creating a clean schematic that surpasses the quality of a subpar schematic editor is possible. The key lies in striking a balance between adhering to rules and being flexible when necessary, much like the advice given by Flannery O'Connor.
- Acknowledging the importance of a clean schematic in both software and aerospace industries, Sutherland suggests that instead of strictly adhering to rules like those in NASA-STD-8739.1 and NASA EEE-INST-002, an optimal schematic might benefit from combining rigorous adherence to guidelines with the necessary flexibility when faced with unique challenges, such as crossing parallel wires with diagonal lines.
- Incorporating elements of data-and-cloud-computing and electronics into this discussion, one might argue that a schematic editor for an ideal hardware system, just like a software developer, must strike a balance between following established standards and being adaptable to various situations, reflecting the advice given by Flannery O'Connor, "You can do anything you can get away with, but nobody has ever gotten away with much."
