PLC, HMI & Industrial Networking

Siemens S7-300 to S7-1500: Migration Basics

S7-300 CPUs and modules show as spare parts with production cancelled. How Siemens' migration guide moves the project, I/O and networks onto an S7-1500.

October 20, 2026

Replacing an Obsolete HMI: Cutout, Comms, Screens

Replacing a dead HMI means matching the panel cutout, the PLC protocol and driver, the power supply and the screen application. How to check each one.

October 20, 2026

Secure Remote Access to PLCs and HMIs

Port forwarding a PLC to the internet is how plants get found. How VPNs, gateways and jump hosts compare, plus MFA, logging and what to ask a vendor.

October 9, 2026

IT vs OT Network Security Basics for Plants

IT protects data; OT keeps machines running safely. How the priorities differ, plus the basics: segmentation, inventory, passwords, removable media.

October 9, 2026

HMI Screen Design Best Practices

Grey backgrounds, colour only for abnormal, a sane alarm philosophy and shallow navigation: HMI screen design that helps operators spot problems early.

October 9, 2026

EtherCAT vs PROFINET vs EtherNet/IP

How the three common industrial Ethernet protocols differ in method, topology, determinism and ecosystem, and how to choose for a given machine.

October 9, 2026

EtherNet/IP Implicit vs Explicit Messaging

Implicit messaging carries cyclic I/O over UDP; explicit messaging is request and response over TCP. How each works, RPI, multicast and common faults.

October 9, 2026

Ladder Logic Basics: Contacts, Coils, Timers

The core ladder logic instructions in plain terms: contacts, coils, latch versus seal-in, timers, counters, compares and one-shots, with a start/stop rung.

October 9, 2026

The PLC Scan Cycle Explained

A PLC reads inputs, runs the program, writes outputs and repeats. How the scan works, why rung order matters, and what slows it down.

October 9, 2026

What Is an Industrial Gateway? What It Connects

An industrial gateway translates between different protocols or networks so equipment that cannot talk directly can share data. Types and what to check.

October 8, 2026

What Is OPC UA and Why Plants Use It

OPC UA is a vendor-neutral protocol for moving industrial data between machines, controllers and software. How it works and what to check before using it.

October 8, 2026

Modbus RTU vs Modbus TCP: What Is the Difference?

Modbus RTU runs over a serial two-wire bus, Modbus TCP over Ethernet. How each works, how to wire the bus, and the settings that cause most failures.

October 7, 2026

How to Learn PLC Programming From Scratch

PLC programming means writing the logic a controller runs. The IEC 61131-3 languages in plain terms, and a practical path to learn them.

October 7, 2026

What Is Node-RED? Where It Fits in a Plant

Node-RED is a flow-based tool for wiring data between devices, databases and dashboards. What it does well, and where a PLC must still do the work.

October 7, 2026

Managed vs Unmanaged Industrial Ethernet Switches

An unmanaged switch just passes traffic. A managed switch adds VLANs, redundancy, QoS and monitoring. When each makes sense in a plant.

October 7, 2026

What Is an HMI? Human Machine Interface Explained

An HMI is the screen operators use to see a machine's status and control it. What it does, the main types, and what to check when choosing one.

October 5, 2026

HMI Touchscreens: Resistive vs Capacitive Explained

Industrial HMI touchscreens use resistive or projected capacitive technology. How they differ and what to check for gloves, water and screen size.

October 1, 2026

What Is a PLC? How a Programmable Controller Works

A PLC is a rugged industrial computer that reads inputs, runs a control program and switches outputs in a repeating scan. How it works and how to choose one.

October 1, 2026

Industrial Ethernet Cable: Category, Shielding, Solid vs Stranded and the 100 m Limit

How to choose industrial Ethernet cable: category, two-pair versus four-pair, solid versus stranded, shielding, jacket and the 100 m channel limit.

September 19, 2026

Machine Vision Basics: Choosing Camera Resolution, Lens and Lighting

How to specify an industrial vision system: the resolution a defect needs, how field of view sets it, lens choice, and why lighting decides whether an.

September 19, 2026

Pneumatic and Electric Grippers: Sizing Grip Force and Stroke

Learn how to size grip force and stroke for industrial grippers, including force calculations, safety factors, and considerations for pneumatic vs. electric.

September 19, 2026

PLC I/O Signal Types: A Wiring Reference

A practical wiring reference for PLC digital, analog, and temperature I/O: sinking versus sourcing, leakage current bleed resistors, 4-20mA loops, and RTD.

August 11, 2026

Industrial Ethernet Protocols: A Comparison Reference

EtherNet/IP, PROFINET, EtherCAT, Modbus TCP and POWERLINK share the RJ45 connector but are not interchangeable. This reference breaks down determinism, cycle.

August 11, 2026

Remote I/O vs Centralised I/O: An Architecture Reference

Comparing centralised and remote I/O architectures: wiring economics, panel space constraints, IP20 versus IP67 on-machine blocks, network dependency, and node.

August 11, 2026

Electromechanical vs Solid State Relays: A Reference

A practical comparison of electromechanical and solid state relays covering galvanic isolation, leakage current, zero-cross turn-on, heat derating.

August 11, 2026

Selecting an HMI: Size, Environment and Interface

A practical guide to choosing the right HMI screen size, touch technology, environmental rating and communication features for reliable operator interfaces.

August 11, 2026

Sizing a Control Panel Power Supply

A step‑by‑step guide to selecting a 24 VDC supply that handles continuous load, inrush peaks, temperature, altitude, and redundancy requirements.

August 11, 2026

Timer Relay Functions: On-Delay, Off-Delay and the Rest

A technical guide to timer relay functions—on‑delay, off‑delay, one‑shot, flasher, star‑delta and multifunction units—plus when to use hardware timers versus.

August 11, 2026

Monitoring Relays: Phase, Voltage, Current and Level

Technical guide to phase, voltage, current, insulation and level monitoring relays, covering setpoints, hysteresis, delays and fail‑safe wiring for reliable.

August 11, 2026