The four-level BAS architecture in depth — field, controller/DDC, supervisory, and enterprise/IT — network topology, how a point flows from sensor to supervisory software, open vs. proprietary architectures, and typical hardware at each level.
Module 1 introduced the BAS as a building's central nervous system through analogy alone. This module makes that structure literal: the field level's sensors and actuators, the DDC level's local reflex-arc control and field-bus networking, the supervisory level's aggregation and operator interface, and the enterprise/IT level's data, analytics, and business-system integration — each with its own hardware, responsibilities, and relationship to the levels above and below it.
By the end of this module you should be able to trace a single point — a space temperature sensor — end-to-end through all four levels, and explain why keeping control logic distributed at the DDC level, rather than centralized at the top, is what makes a BAS resilient rather than fragile. Module 3 picks up BACnet, the protocol that ties these levels together, and Module 4 goes deep on the DDC controller hardware this module only introduces.