It's reasonably common for LaTeX documents to use PSTricks or PGF/TikZ or Asymptote to specify diagrams as text, within the main document. However, these use textual descriptions of diagrams, rather than ASCII-art pictures of them.
I think before there were GUI tools for editing ladder diagrams [0], there were tools that would read ASCII-art diagrams, and program PLCs with the corresponding logic. However, a quick Google didn't give a source confirming this.
I think before there were GUI tools for editing ladder diagrams [0], there were tools that would read ASCII-art diagrams, and program PLCs with the corresponding logic. However, a quick Google didn't give a source confirming this.
[0]: https://en.wikipedia.org/wiki/Ladder_logic https://en.wikipedia.org/wiki/PGF/TikZ