Process control:
teach the machine to hold steady.
PID loops are the other half of industrial control. Instead of making things move, they make a number (temperature, pressure, flow or level) hold steady against a world that keeps disturbing it. This module builds the whole skill from the wire up: analog scaling and the 4–20 mA live zero, PV/SP/CV and the closed loop, the proportional term and its offset, integral and derivative, windup and bumpless transfer, and hand tuning. It ends with a pasteuriser capstone you can break and repair. There are six chapters, each with a live loop to play with.
Three terms, every vendor
🧩 PID_Compact, PIDE, FB_CTRL_PID, PIDAT, PIDFF: every platform builds its block on the same three terms. The wrappers differ in form (ideal, parallel or series) and in how gain is entered (gain or proportional band). Learn PV/SP/CV and the three terms once and you can tune loops anywhere.
Feel it, don't memorise it
🎚️ Every chapter has a live process: drag the gains, break the sensor wire, wind up the integral, dump cold product in. You build each PID instinct by hand, on a loop that answers back.