VERY complex systems and concepts can be explained to anyone via analogies to things they already understand. Bang-bang logic is easy to explain and understand. PID is hard, but you can equate it to something like balancing on one foot and it gets easier. Break SCADA down into digestible chunks and it's not impossible to explain it to your 90-year-old grandmother.

This applies to your understanding of whatever you're teaching. If you can't ELI5 then you probably don't know enough about whatever concept you're trying to explain - that's your cue to keep learning until you can.

Caveat: For a blog or industry audience, you don't have to "dumb down" your answers if you're using technical jargon or even equations and the like. Being able to explain something in simple terms doesn't preclude talking about minutiae or nerdy technical details.

For technical topics I often envision a smart college sophomore who might be considering a major in which your topic resides. With this I can assume a pretty decent general education but little or no domain knowledge.

Assuming a smart college sophomore means that they have ability to follow pretty detailed or involved reasoning but they need the groundwork of concepts and terminology explained.