Batch Control & ISA-88:
production by recipe.
Some plants hold one steady state forever. Some make discrete parts one at a time. And some (breweries, pharma, specialty chemicals, food) produce in BATCHES: they follow a recipe of timed, ordered steps with a clear beginning and a clear end. Batch is its own discipline, and ISA-88 is the standard that tamed it. Its central idea is a beautiful one. Keep the RECIPE (what to make) cleanly apart from the EQUIPMENT (how to make it), so one recipe runs on any capable unit and one unit runs any suitable recipe. This module builds that model one piece at a time: the physical hierarchy, the procedural hierarchy, the separation between the two and the state engine. It all sits on top of the ISA-95 pyramid from D14, where batch execution lives at Level 3.
What, not how
⚗️ a recipe says 'add 50 kg, heat to 67 °C, hold 60 min' and never names a specific tank, valve or pump. Knowing how to do those things is the equipment's job. Keep the two separate and the same recipe scales to any plant, any unit and any size.
A batch has a life story
📋 unlike a continuous loop, a batch starts, runs ordered phases, can pause/hold/restart, and ends. Along the way it leaves a full genealogy for every lot: which materials went in, which equipment ran it and which operator was in charge. Regulated industries live on ISA-88 because of that record.