Posts on Ian's World

The Dependency Problem: What Axios Taught Us About OT Edge Platforms

ian@ianloke.com (Ian Loke) — Thu, 16 Apr 2026 16:00:00 +0800

I ran npm install on a Raspberry Pi 4, the same one I’d set up as an edge gateway with OPC UA and MQTT, and watched the terminal scroll.

Node-RED, plus three protocol modules for Siemens S7 PLCs, OPC UA, and Modbus. When it finished, I counted.

What Happens When You Push OPC UA and MQTT Through a Data Diode

ian@ianloke.com (Ian Loke) — Thu, 16 Apr 2026 15:00:00 +0800

IEC 62443 defines four Security Levels for industrial control systems. At the highest level — SL-4, protection against state-sponsored attacks with extensive resources — the standard calls for unidirectional data flow enforcement. Not a firewall rule. Not a software policy. Hardware-enforced, physically one-way communication.

Building an IT/OT Edge Gateway with a Raspberry Pi

ian@ianloke.com (Ian Loke) — Thu, 19 Mar 2026 12:00:00 +0800

Every factory faces the same question: how do you get sensor data from the shop floor to the systems that need it? The answer is never one protocol. It’s two — MQTT for vertical data flow to IT systems, and OPC UA for horizontal integration with SCADA and HMI on the plant floor.

WinCC Unified - Clamping Tag Value

ian@ianloke.com (Ian Loke) — Tue, 11 Feb 2025 21:14:01 +0800

In my previous post, I shared the importance of setting tag limits to prevent bad data from causing issues in SCADA systems. Now, let’s talk about another essential safeguard — clamping values.

WinCC Unified - Setting Tag Value Limit

ian@ianloke.com (Ian Loke) — Mon, 10 Feb 2025 16:31:10 +0800

Since WinCC Unified V17, users have been able to set upper and lower limits for tags to ensure the value stays within a defined range. This feature is essential for preventing invalid inputs and protects connected devices from unexpected inputs.

Deploying Nikola Site to Cloudflare Pages

ian@ianloke.com (Ian Loke) — Sat, 08 Feb 2025 10:22:04 +0800

This site is built on Nikola and deployed on Cloudflare Pages. Being a static site generator, you are able to deploy your Nikola site to Pages by following the Static HTML Guide.

As an example, here is an example of Cloudflare Pages settings for a Nikola site hosted on a Github repository.

Enabling Wi-Fi Channel 13 on the RPi in Singapore

ian@ianloke.com (Ian Loke) — Sun, 20 Oct 2019 14:26:26 +0800

If you are attempting to connect your Raspberry Pi to a 2.4 GHz Wi-Fi channel greater than 11 (i.e Channel 12 and Channel 13), there is a chance that the channel is not exposed to you.

Singapore FM Radio with HackRF One

ian@ianloke.com (Ian Loke) — Sun, 14 Jul 2019 14:26:41 +0800

It’s been a while since I’ve posted due to different excuses. But no more, I hope to continue posting articles regularly in the spirit of learning about new technology. Today’s tech gadget is the HackRF One by GreatScottGadgets. The HackRF One is a Software Defined Radio (SDR) hardware used to test and develop radio technologies.

How Do IR Flame Detectors Work?

ian@ianloke.com (Ian Loke) — Mon, 08 Apr 2019 21:50:52 +0800

As a gas turbine controls engineer, part of my job involves working with ancillary systems such as the fire and gas system. In gas turbine packages, fire and gas systems are used to detect fires and flammable gases which are hazards to the operating environment.