SCADA vs HMI vs PLC
SCADA, HMI, and PLC get used almost interchangeably in job postings and casual shop-floor conversation, but they aren't competing technologies, they're three different layers of the same control system, each doing a distinct job.
SCADA, HMI, and PLC get used almost interchangeably in job postings and casual shop-floor conversation, but they aren't competing technologies, they're three different layers of the same control system, each doing a distinct job.
Inductive, capacitive, and photoelectric sensors all answer the same basic question, is something there?, but they sense completely different physical properties, and picking the wrong type is one of the most common causes of unreliable machine behavior on the plant floor.

This is a full build-along tutorial that goes beyond the Bob Teaches Tech YouTube video. It covers the hardware, wiring, GX Works2 project setup, and explains each step of an automatic timer loop sequence on a Mitsubishi FX3U PLC. You'll also find 15 real-world uses, 20 common beginner mistakes, a troubleshooting guide, and over 35 frequently asked questions.
SCADA lets a single operator monitor and control equipment spread across an entire plant, pipeline, or utility network — here's what the acronym actually means, the five components every system shares, and how it differs from a standalone PLC or a full DCS.
Structured text (ST) is the IEC 61131-3 language that feels most familiar to anyone with a Pascal or C background - and it's becoming the go-to choice for sequencing, math-heavy, and recipe-driven logic that turns unreadable in ladder.

Modbus register types explained: coils, discrete inputs, holding and input registers, function codes, and addressing conventions.
PLC data types explained: BOOL, INT, DINT, REAL, arrays, and structures-with a real scaling bug example and vendor comparison.
Learn PLC counter instructions (CTU, CTD, CTUD) with tested ladder logic examples, reset logic, and common beginner mistakes explained.

In PLC programming, the control of time is an essential factor when it comes to timely control in automation. Learn how to represent timers in the Mitsubishi's MELSEC series FX-3u PLC using the GX Developer software.
Learn how on‑delay timers (TON) work in PLC ladder logic, how to set presets and accumulated values, and explore real‑world applications such as conveyor startup delays. This beginner’s guide from Bob Teaches Tech covers every detail to help you master…