Controller Area Network Solutions

10/02/2026

I like talking about Modbus RTU.

Introduced in 1979, Modbus RTU is the cockroach of industrial communication protocol, ancient, older than many engineers wiring it today. Yet walk into a substation in 2026, you’ll still find RS-485 trunks daisy-chained across meters, VFDs, temperature controllers, remote I/O, etc crawling around your panel while shiny new Ethernet-based protocols argue about bandwidth.

Modbus lacks of modern security features. It has no built-in security, no device discovery, not connection baded. It was simply not designed for cybersecurity exposed networks. Running naked Modbus RTU over the public internet is like leaving your substation door open with a sign saying “come attack me”.

So why is it still here?

Because physics doesn’t care about fashion.

Modbus RTU runs over RS-485, which is a single design choice that makes it ridiculously immune to noise. Long cable runs? 500 meters? 1 km with good cable? No problem. EMI from motors? Manageable. In harsh industrial environments, simplicity beats sophistication.

Modbus is transparent. No licensing. No vendor lock-in. No stack royalty. The frame is simple: address, function code, data, CRC. You can decode it with a logic analyzer and a notebook. Engineers like that.

Modbus RTU is deterministic enough for its job. It is master-slave. Only one master talks at a time, eliminating collision chaos. It’s slow by modern standards, 9.6 kbps, 19.2 kbps, maybe 115.2 kbps, but sufficient for reading temperature, energy kWh, vibration RMS.

Modbus RTU has varse installed base. This is the economic gravity argument. Millions of field devices are speaking Modbus RTU, for instance energy meters, protection relays, power analyzers, PLCs, vibration sensors, weighbridges. Replacing all of them just to upgrade protocol would be financial stupidity. Engineering is constrained by CAPEX, not elegance.

Modbus bridges beautifully. Modbus RTU to Modbus TCP gateways are cheap. You can hang legacy RTU devices under a modern SCADA, MQTT broker, or cloud EMS platform without rewriting firmware. It becomes the “last-mile” field layer while higher layers evolve.

Unlike consumer market, industrial systems have a 20 to 30 years lifecycle. Software culture moves fast but industrial hardware moves like continental drift. In slow tectonic systems, stable protocols survive. Old does not mean obsolete, it means proven. The scientific method rewards repeatability. Modbus RTU has been tested in lightning storms, factory floors, and dusty switch rooms for decades. It behaves predictably. Predictability is gold in automation.

Modbus RTU is not glamorous, neither trendy, but it works. The golden rule in industry, “works every day for 25 years” beats “innovative but fragile” every single time.

Old technology survives when it solves the right problem efficiently. Modbus RTU still does.

24/12/2025

Merry Christmas!

21/12/2025

Happy winter solstice!

23/02/2025

Know anyone who is interested?

Dipaparkan 6:07:46 PG. Company Description Controller Area Network Solutions (M) Sdn Bhd (CANS) is a provider of…Lihat ini dan pekerjaan yang serupa di LinkedIn.

14/12/2024

Recently, I’ve noticed a growing trend where many factories are migrating their Building Management Systems (BMS) to Supervisory Control and Data Acquisition (SCADA) systems, specifically replacing Direct Digital Controllers (DDCs) with Programmable Logic Controllers (PLCs).

The rationale behind this shift is unclear—perhaps it is an attempt to standardise components—but this transition carries significant risks.

While factory automation (PLC) and building monitoring (BMS) fieldbuses may appear similar, or even identical, to the untrained eye, they serve distinct purposes. Automation fieldbuses are optimised for speed and real-time control, whereas BMS fieldbuses are specifically designed for the nuanced requirements of building systems.

Take BACnet, for example—a widely used BMS protocol. One of its key features is Priority, a mechanism that allows multiple commands to be issued to a DDC with varying levels of precedence. The DDC will always execute the highest-priority command until it is relinquished, after which it reverts to the default value.

Why is this feature critical?

Consider a scenario where a roller shutter is programmed to close automatically during a fire to prevent the spread of flames. If a security manager spots a worker trapped inside the room, he or she can issue an override command with higher priority to open the shutter, enabling the worker to escape. Once the situation is resolved, the override can be relinquished, and the shutter resumes its default behaviour.

Some may argue that similar functionality can be achieved through application-level PLC programming. While theoretically true, this approach introduces significant risks. The safety of personnel would depend entirely on the system integrator's programming expertise, requiring rigorous Factory Acceptance Testing (FAT), interoperability testing, and Site Acceptance Testing (SAT) to ensure reliability. Even then, achieving the same level of robustness and standardisation as a protocol like BACnet is challenging.

It’s important to remember that BMS protocols such as BACnet wasn’t developed arbitrarily. ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) designed this feature-rich protocol specifically to address the complex needs of building monitoring and control systems. By replacing DDCs with PLCs, factories risk compromising the very safeguards that BMS protocols like BACnet are designed to provide.

08/01/2024

Shanghai Pudong Airport Terminal 2 in the early morning, surprisingly empty.

01/01/2024

Happy New Year to all!

13/11/2023

I shared my view in a recent conversation, which I stated humans are simply the intermediary existence to catalyse the evolution of robots.

At one point when the robots become so intelligent that they are able to harvest energies and reproduce themselves, humans will become redundant.

The robots are in their ultimate forms for the interstellar travelling, they do not need oxygen, do not suffer from radiations, and they last vietually forever.

What does the future of work look like a hundred years from now? Will AI really eliminate the need for jobs? Here's what you need to know as the market evolves.

12/11/2023

Happy Deepavali!!

11/11/2023

May the festival of lights illuminate your life with joy, prosperity, and good health.
Happy Deepavali to you and your family

06/06/2023

Having one of the most traditional Malaysia breakfasts at one of the most eco high tech areas in Malaysia - Tamarind Square, Cyberjaya.

03/05/2023