PLC architecture and the scan cycle, ladder logic and IEC 61131-3, timers and counters, interlocks and safety-rated logic, plus the fieldbus, industrial Ethernet, OPC UA, MQTT, and wireless protocols that tie an automation system together.
This module extends the sense-think-act architecture from the device level covered in Module 8 up to the system level, where a PLC coordinates dozens or hundreds of I/O points on a deterministic scan cycle, and where PLCs, drives, sensors, and supervisory systems all have to exchange data reliably over a shared industrial network. Ladder logic, function block diagrams, structured text, timers and counters, and interlock and safety-rated logic are covered first, followed by the communications landscape a real plant actually runs on: Modbus, EtherNet/IP, PROFINET, CAN bus, OPC UA, MQTT, and industrial wireless.
A worked scan-cycle timing budget anchors the PLC-architecture half of the module in real numbers, and a worked case-counting example ties timers and counters to an actual production task — the same practical grounding this program applies throughout.