Without disturbing existing systems, edge devices make it easy to convert data from a custom fieldbus into open protocols for digital transformation.

If TCP/IP won the “protocol wars” in the ‘90s, then WHY are you still fighting protocol battles on the plant floor today? Because industrial networks were around long before the internet. As far back as the 1960s, machines communicated via serial networks like RS-232, RS-485, and CAN Bus—with specialized proprietary fieldbus protocols like Modbus, Profibus, and DeviceNet.

Even with TCP/IP on Ethernet, specialized protocols remained. Modbus now has a TCP/IP version, Profibus gave way to ProfiNET, DeviceNet to EtherNet/IP, and even some new ones joined the protocol party.

After the industry demanded interoperability, OPC was born—now OPC UA—a big step toward a unified architecture on OT networks. Meanwhile on the IT side, using HTTP and HTTPS was common. It’s how web browsers—and most of the internet—work today.

MQTT Sparkplug came later. A recently named International Standard, it’s built on efficient, secure, and scalable publish/subscribe communications—a great fit for digital transformation projects and the IIoT.

You’re not alone.

HUNDREDS OF BILLIONS of legacy industrial controls systems are still in operation today. The old adage, “If it ain’t broke, don’t fix it,” often delays digital transformation.

So should you put off digital transformation while waiting for existing systems to fail, or spend a ton ripping and replacing your controls to support the latest protocols?

Modern Edge Devices Save the Day

Thanks to modern edge devices—computing systems that process data locally at the source—you don’t have to make that choice.

Inexpensive devices available now can either work with your existing PLC system or run in parallel to get your plant floor data securely where it’s needed—your IT network, remote servers, even the cloud.

Serial protocols - Many factories have long-standing equipment that relies on serial communications. Even some new systems use serial comms for reliability, simplicity, and cost-effectiveness.

Thankfully, the latest edge devices include serial ports and software tools for RS-232, RS-485, and CAN Bus—everything from simple USB-to-serial interfaces through dedicated, configurable, multi-channel I/O modules.

You can achieve bidirectional serial communication in open programming platforms like Node-RED, JavaScript, Python, C++, and more. Or, if you prefer ladder diagrams and function blocks, use an IEC 61131-3 compliant PLC programming platform.

Ethernet-based Fieldbuses - PLCs sold today all run Ethernet-based fieldbuses. They’re suited for coordinated motion-control applications—where low latency and precise synchronization are paramount—but they may not fit for digital transformation.

Thankfully you don’t have to rip and replace your PLCs. Edge devices today have SCADA tools and programming platforms with native drivers for all the most popular protocols. Without disturbing existing systems, edge devices make it easy to convert data from a custom fieldbus into open protocols for digital transformation. 

OPC UA - One of those open protocols is OPC UA, which creates interoperability among PLC and I/O platforms. You’ll find options for both client and server functionality on the latest edge devices.

Native OPC UA servers expose I/O values from physical modules. SCADA-supported OPC UA servers provide southbound connectivity to fieldbuses and northbound connectivity to HMI dashboards and historians. And both clients and servers in IEC 61131-3 compliant PLC programming platforms provide endless interconnectivity options.

REST API - A common method for passing information across IT infrastructure, these APIs are a standard way to use HTTP or HTTPS messages to send and receive data in common formats like XML or JSON.

IT and programming professionals use tools like Swagger to understand, test, and integrate with someone else's API by exploring documentation, trying out endpoints, and generating client code for seamless integration.

And yes, modern edge devices support this technology as well, enabling them to communicate using methods familiar to IT professionals.

MQTT Sparkplug - The latest in IIoT communications employs a publish/subscribe architecture. Originally designed for an industrial SCADA application, MQTT Sparkplug should be at the heart of any digital transformation project.

With MQTT’s Unified Namespace (UNS), you can model your data with context and create a plug-and-play architecture for all your machines. Your edge device gives you a single source of truth for your data where it originates and then securely publishes your data where it’s needed. Result? You can use the latest in machine learning, artificial intelligence, advanced analytics, and anomaly detection.

Where to Begin? 

Start small. Prove ROI with a small investment. Find an edge device that’s commercially available off-the-shelf and speaks the protocols your plant runs today. Once you’ve proven it will work, it’s time to expand.

And here are a few more resources from the Opto 22 website that can help you get started:

• Why groov EPIC
• groov EPIC Software
• Get started with MQTT
• Cybersecurity