No doubt. Good advice,
A moot point anyway, since my mini doesn't have Function Block and all my researching points that way for the PIDE autotune etc... latest and greatest Studio 5000. So when I open my free 30 days of emulate 5000 next month, which will have the function block, I'll dig a little then.
Happy Thanksgiving to all.
In all brief seriousness, it seems fundamental;
Proportional: a little off the SP, a little response and a lot off the SP, a lot of response, with basic physics ie... negating or opposing forces, (heat radiating from an oven, water in a discharge line being used thereby continuously dropping the pressure the pump is trying to raise thereby giving us a PV settling below the SP.)
Integral being the reaction to a cumulative error adding up over time to reach nearer the setpoint with derivative keeping an eye on rates of change ascent, descent, avoiding overshoot and other graphical tendencies .. Being an old MGD water flow meter calibrator using venturis, orifice plates and pressure differential, I did have to develop a must learn this stuff mentality, but I've worn it out now so to quote Kramer.
"I'm through with it starting... Now." : )
Tx again, back to programming