The theory, briefly

Flintloop fits one model and tunes against two numbers. You do not need the maths to use it, but if you are going to write gains into a plant you should be able to check the tool, so here it is in three short pages.

The pieces

• The FOPDT model – gain K, time constant T, dead time L, and why three parameters are enough for most loops.
• Stability margins – what gain margin and phase margin mean and why the defaults are 2.0 and 45°.
• Dead time – the one parameter that quietly decides how aggressive you can be.

None of this is novel; it is the standard first-order treatment you would find in any controls text, written down so you can see which equations the program is actually using.