All five IEC 61131-3 languages — Ladder Diagram, Function Block Diagram, Structured Text, Sequential Function Chart, and Instruction List — plus timers, counters, math, state machines, sequencers, PID control, and alarm logic.
Module 3 built the execution engine underneath a PLC — the CPU, memory, and scan cycle. This module builds on top of it: the five standardized programming languages every modern platform supports, why real programs mix several of them in the same project, and the shared instruction toolkit — timers, counters, math, comparisons, data movement — that every one of those languages ultimately calls on.
By the end of this module you should be able to structure a real sequence as a state machine or an SFC rather than a pile of interlocked bits, explain what anti-windup actually protects a PID loop against, and know why alarm rationalization is a required engineering deliverable rather than an afterthought — the exact discipline ISA-18.2 formalizes and Module 12 (Industrial Safety) covers in full.