In process industries like oil and gas, chemical, paper, and water treatment, precision is everything. That’s why PLCs—once simple relay replacers—have evolved into powerful, real-time control hubs capable of enabling intelligent operations across increasingly connected systems. To explore how PLC technology is transforming process control, we spoke with Jeff Payne, Director of Business Development at AutomationDirect.
With more than 25 years at the company and deep experience leading its PLC portfolio, including launching the CLICK and Productivity series, Jeff offers practical insight into how CPU power, fieldbus connectivity, and IIoT integration are converging to help engineers solve today’s most complex automation challenges.
How has the role of PLCs in process control evolved over the past decade, particularly in industries like oil and gas, water treatment, and paper production?
The evolution has been dramatic. Ten to twenty years ago, PLCs were primarily used for discrete control—basic sequencing and on/off decisions. But process industries are among the most demanding users of automation, and they’ve pushed PLCs to grow up fast. Today’s process control applications require rapid data acquisition, continuous monitoring, tight loop regulation, and increasingly, seamless connectivity to business-level systems.
That’s where modern PLCs shine. They now offer greater processing power, more memory, and built-in support for industrial communication protocols like MQTT and OPC UA. This makes it easier to feed process data into cloud platforms or enterprise analytics tools in near real time. Add to that smaller hardware footprints, better thermal performance, and competitive price points, and PLCs have become a flexible, powerful tool for process control across a broad range of industries—not just the traditional ones.
What key challenges do process control applications face today, and how do modern PLCs help address them?
At the heart of any successful process control system is real-time insight—knowing exactly what’s happening inside your system as it happens. That starts with tight feedback loops and reliable access to process variables like flow, pressure, or temperature. But many engineers still struggle with visibility—especially when legacy systems or disconnected devices make it hard to access and act on that data.
Modern PLCs are addressing this by becoming more open and connected. New platforms now integrate easily with IIoT tools and business systems, offering direct access to memory locations and real-time data exchange. Communication technologies like MQTT and OPC UA make it easier to bridge the gap between operations and IT, so engineers and decision-makers alike can view performance, predict maintenance needs, and adjust parameters on the fly. In effect, the PLC is no longer a black box. It’s an open book—and that’s a big shift.
AutomationDirect offers a wide range of PLCs. What are the key differences in how your various models handle process control applications?
All our PLC families—from CLICK to Productivity to BRX—can handle core process control tasks like digital I/O, analog signals, and PID loop control. Where they really differ is in processing power, memory, and communication capabilities—especially when it comes to integrating OT data into IT systems.
Take our BRX series, for example. It’s one of our most advanced platforms and includes built-in support for MQTT, OPC UA, and Node-RED. That makes it especially well-suited for process applications that demand real-time visibility, remote access, or cloud integration. On the other end of the spectrum, our CLICK series is ideal for smaller, cost-sensitive process systems that still need analog control but may not require all the bells and whistles.
We also offer free programming software and built-in simulators across all our platforms, so engineers can test code and functionality before committing to hardware. That’s a big help when choosing the right PLC for the job.
How has the transition from analog PID loops to digital PLC-based control improved precision and reliability?
Traditional analog PID loops were effective but labor-intensive. Engineers would often have to wait for a process batch to complete, gather quality assurance results, then manually tweak tuning parameters—a cycle that could take hours or even days. With digital PLC-based PID control, that feedback loop becomes much faster and more dynamic.
Modern PLCs can ingest process variable data in real time and adjust control parameters almost instantly. This responsiveness improves not just the precision of the control loop, but also its reliability—because you’re constantly monitoring actual conditions and adjusting accordingly. And when you pair that with cloud connectivity, engineers can now monitor, analyze, and even update control logic remotely.
The result is faster commissioning, more consistent product quality, and less downtime. Whether you’re mixing chemicals, managing wastewater, or producing food products with recipe-driven variations, the advantages of digital PID control are night and day compared to the old analog approach.
What advancements in PLC CPU processing power have had the greatest impact on real-time control and efficiency?
One of the biggest leaps forward has been the adoption of multi-core processors in PLCs. Early PLCs were basically state machines, executing everything sequentially. That structure still serves us well for ladder logic and deterministic control, but today’s systems also need to manage asynchronous tasks—like communications, motion control, or data logging—all at the same time.
Multi-core architectures allow us to split those tasks across different processor segments. You can dedicate one core to the control logic and others to handling communication protocols or background data processing. This makes the entire system exponentially more efficient. You’re no longer stacking up asynchronous tasks at the end of each scan cycle and slowing things down.
So, while scan-time consistency remains critical, modern PLCs can now do far more in parallel—without compromising the reliability or predictability that engineers expect. That’s a big reason PLCs remain the control platform of choice, even as industrial applications grow more complex.
How are modern sensors and I/O modules enhancing PLC functionality in process industries?
Sensors and I/O modules have come a long way in recent years—especially with the widespread adoption of IO-Link. What used to be simple binary devices are now rich sources of diagnostic and performance data. Instead of just knowing whether a sensor is on or off, engineers can now monitor signal strength, device health, internal temperature, and even maintenance schedules in real time.
This added intelligence helps improve both system uptime and troubleshooting. In a traditional setup, you might not know a sensor was failing until the process went off-spec. With IO-Link-enabled devices, you get early warning signs and actionable data long before a failure happens. That’s a huge boost for predictive maintenance strategies.
It also simplifies configuration. Instead of hard-coding sensor parameters, IO-Link lets you adjust settings directly from the PLC. All of this translates to smarter, more flexible systems that are easier to manage and scale.
How does PLC integration with IIoT help optimize process control and predictive maintenance?
IIoT integration takes the power of PLCs and extends it well beyond the control panel. By connecting PLCs to cloud platforms or enterprise-level systems, you’re turning raw machine data into actionable insight—available in real time, from anywhere. That’s a major advantage for process applications where uptime, efficiency, and product consistency are all on the line.
It also enables predictive maintenance. When a PLC can share data about equipment status, environmental conditions, or performance trends, you can start to anticipate issues before they cause downtime. That’s a big step up from reactive maintenance, which often comes too late and costs more.
But here’s the key: the technology is already there. Tools like MQTT, OPC UA, and Node-RED make it relatively easy to push data from the shop floor to the cloud. If an operation isn’t leveraging this kind of integration, it’s usually not because it’s impossible—it’s because they haven’t yet taken advantage of what modern PLCs make possible.
For engineers choosing a PLC for process applications, what are the most critical factors they should consider?
It starts with understanding the demands of your specific application. For process control, that often means prioritizing CPU performance, memory capacity, and communication capabilities. You need a platform that can handle continuous data collection and PID loop execution—while also managing asynchronous tasks like network communications or remote diagnostics.
Engineers should also consider how easy it is to scale and maintain the system. Does the PLC support simulation tools for development? Does it offer native integration with IIoT protocols like MQTT or OPC UA? Can it work with intelligent I/O like IO-Link? These factors make a big difference over the lifecycle of the control system.
Finally, don’t underestimate the value of software. Free, intuitive programming environments—like what we offer at AutomationDirect—can save both time and cost. And when you combine that with flexible hardware platforms, you get a solution that’s not just powerful, but practical for real-world process environments.
* * *
Choosing the Right PLC from AutomationDirect
AutomationDirect offers a full range of PLC platforms suited for process control—from compact systems for basic analog and PID tasks to advanced controllers with IIoT-ready capabilities. Here’s a quick look:
- CLICK PLC Series
Ideal for smaller-scale applications requiring basic analog I/O and PID control. CLICK PLUS models add Ethernet and Modbus TCP connectivity, while the C2-NRED module enables Node-RED integration for easy IIoT access and visualization. - Productivity Series (P1000, P2000, P3000)
Offers scalable power for more complex process applications. These controllers feature high-speed I/O, built-in PID functions, and strong tag-based programming support. Productivity Suite software is free and packed with simulation and troubleshooting tools. - BRX Series PLCs
Built for high-performance, high-connectivity environments. Designed and manufactured in the USA, BRX models include advanced features like MQTT, OPC UA, and HTML5 web server support—making them an excellent choice for cloud-connected, data-driven process systems.
Whether you’re managing a chemical blend, monitoring pump performance, or fine-tuning a recipe, AutomationDirect has a PLC platform built to fit the task.