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.
Category Tech Articles
Read MoreSCADA vs HMI vs PLC
How to Wire a Photoelectric Sensor to an AC Timer Relay
Learn how to connect a 24V DC photoelectric sensor to an AC timer relay using an interposing relay. Complete wiring guide with diagrams, explanations, and troubleshooting.
Proximity Sensors Explained: Inductive vs Capacitive vs Photoelectric
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.
How to Build a PLC Timer Loop Sequence
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.
What Is SCADA? Architecture, Components, and How It Works
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.
Arduino Digital I/O Explained: pinMode, digitalRead, digitalWrite
Arduino digital I/O explained: pinMode, digitalRead, and digitalWrite with a tested button-and-LED wiring and code example.
Structured Text Programming for PLCs: A Practical Introduction
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 Registers
Modbus register types explained: coils, discrete inputs, holding and input registers, function codes, and addressing conventions.
How to Set Up a Modbus TCP Connection Between a PLC and SCADA
Step-by-step guide to connecting a PLC to SCADA over Modbus TCP, including port 502 setup and a troubleshooting table.
PLC Data Types Explained: BOOL, INT, REAL, and Structures
PLC data types explained: BOOL, INT, DINT, REAL, arrays, and structures-with a real scaling bug example and vendor comparison.