Managing a single PLC is straightforward: one tool suite, one task. But as industrial systems grow, so does complexity. A diverse fleet of PLCs from different manufacturers introduces a web of challenges: matching tools and licenses, maintaining a consistent codebase, and deploying updates across various hardware platforms. These obstacles can slow operations, increase costs, and raise the risk of errors.
This blog explores a vision for overcoming these challenges by centralizing system oversight, leveraging version control, and adopting virtual PLC technology. By breaking free from the 1:1 relationship between PLCs and their engineering software, industries can achieve greater efficiency, flexibility, and control in maintaining their automation systems.
What is a Virtual PLC?
The rise of virtual PLCs introduces a new paradigm. Unlike physical PLCs, a virtual PLC operates within software environments, which can be hosted on various hardware configurations or even in the cloud. This separation of control logic from dedicated hardware has the potential to reshape industrial automation. However, “virtual” does not necessarily mean there is no hardware involved—it simply means that the hardware is less specialized, offering more flexibility in its application.
Coupled with a cloud-native platform for centralized work processes like programming, maintenance, and version control, a powerful foundation for efficient PLC operations at scale is laid. For more on this, we’ve covered it in detail in these blog posts: How a Virtual PLC Solves Your 3 Major Automation Problems and How Do Virtual PLCs Untangle Spaghetti Architecture in Operational Technology?
What do we mean by a “fleet”?
A “fleet” refers to a collection of interconnected PLCs (Programmable Logic Controllers) or virtual PLCs distributed across different layers of an industrial system, often managing diverse tasks and spanning multiple physical locations. A fleet isn’t just about the number of PLCs; it encompasses the intricate ecosystem of hardware, software, and communication protocols that allow these devices to work together.
For example, in a district heating network, a fleet may consist of hundreds or thousands of PLCs controlling heat exchange substations, each responsible for specific operational functions. These PLCs may differ by manufacturer, communication protocol (e.g., Modbus, EtherNet/IP), or even hardware generation, but they must collectively function as a cohesive unit.
Five Key Technical Challenges in Managing Fleets of Multi-vendor PLCs
Consider a plant with PLCs from different vendors, each controlling distinct subsystems. Each PLC has its own firmware, communication protocols, and vendor-specific programming environments. When introducing changes or rolling out updates to this sensitive ecosystem, the engineering team faces a cascade of challenges: matching firmware versions, ensuring interoperability between proprietary protocols, and verifying that the updated control logic doesn’t disrupt interdependent systems. Even a small misstep, such as a version mismatch or an overlooked dependency, can cause unplanned downtime or erratic system behavior.
There is a wide range of challenges associated with the operations of a large number of PLCs, or in short, PLC Ops, that can be categorized broadly as follows:
Monitoring and Diagnostics
Data Volume: Monitoring a large number of PLCs generates a significant amount of diagnostic data, requiring centralized tools to avoid manual checks.
Anomalies: Identifying patterns or trends in failures across multiple devices can be time-consuming without automated analytics.
Rolling Out Updates to PLC Programs
Deployment Time: Updating programs manually across many PLCs is labor-intensive, especially if each PLC requires a direct connection.
Synchronization: Ensuring updates are deployed at the same time and preventing discrepancies in program versions across PLCs.
Version Control: Avoiding confusion between different versions of backups for each PLC.
Testing at Scale: Simulating the collective behavior of all PLCs to ensure updates won’t disrupt operations can be difficult.
Multiple Engineering Tools
Tool Licensing and Maintenance: Managing licenses, updates, and support contracts for multiple tools can be complex and expensive.
Learning Curve: Operators need to learn and stay proficient with different engineering tools, each with unique interfaces, workflows, and capabilities.
Incompatibility Across PLC Brands
Programming Languages and Standards: Despite the adoption of IEC 61131-3, PLC programming languages may vary slightly between manufacturers, causing compatibility issues.
Communication Protocols: Different PLC brands may use proprietary or incompatible communication protocols (e.g., Modbus, Ethernet/IP, PROFINET), making it difficult to establish seamless communication across devices.
Firmware Updates: Keeping firmware consistent across brands often requires separate processes and tools for each type of PLC.
Security Challenges
Access Control: Ensuring consistent access control policies across various systems is complicated due to differing capabilities in engineering tools.
How does the Virtual PLC solve the challenge of managing fleets of multi-vendor PLCs?
Many automation vendors offer PLC fleet management to some extent. The risk is obvious: You’re digging yourself deeper into the vendor lock with every layer of vertical integration in your stack. Instead, let’s put some guiding principles in place to enable efficient PLC-Ops.
Open architecture, adherence to open standards, and the introduction of open data frameworks are the basis for achieving interoperability in a diverse ecosystem.
Every device, application, or service must ensure transparency through logs so that troubleshooting and propagation of system health information can be streamlined.
The separation between hardware, firmware, and engineering tools (software) levels the playing field and helps resolve the bottleneck of a one-to-one relationship between a particular PLC and its dedicated programming tool and code base.
The advent of virtual PLC offers the ideal starting point for more efficient PLC Ops at scale. At its very core, a virtual PLC breaks free from the dependency on any particular hardware model or vendor. Thanks to container technology like Docker, the virtual PLC can be deployed rapidly and offer a form of abstraction from the physical devices on which they are installed.
Real-Time Data Integration
They can be deployed and auto-configured alongside a decentralized publish-subscribe data framework. That way, in whichever topology you set up your fleet of virtual PLCs, they come equipped with the capability to share all relevant operational data in real-time with any other application in the stack. In the context of managing fleets of PLCs, this means that logs, heartbeat signals, host device resource consumption, and all other relevant statistics are ready to be fed into graphing and health dashboards giving the operator a comprehensive picture of their automation system at all times.
Version Control
Every virtual PLC provides detailed information about the installed versions of its components, including the runtime and the corresponding instance of its pub-sub data server, as well as the version of the currently executing PLC program. This functionality is critical for enabling operators to track and manage updates efficiently, ensuring code consistency across the system and addressing pending revisions proactively. Such transparency not only simplifies maintenance but also enhances system reliability and reduces the risk of operational disruptions.
Centralized, cloud-native workflow
In industrial automation, inefficiencies frequently arise from the time-consuming tasks of installing, licensing, and managing version compatibility of engineering tools across various devices. A centralized, cloud-native IIoT platform, like OTee, addresses these challenges by delivering a continuously updated front-end application that autonomously handles backward compatibility. This solution simplifies engineering workflows, minimizes setup time, and ensures seamless interaction with PLCs, allowing engineers to dedicate their efforts to enhancing system performance instead of dealing with compatibility and tool management issues.
License-Free Access and Role-Based Security
With the introduction of cloud platforms, license trouble has become a thing of the past. All active subscribers simply log on to their account via web browser, and role-based access control (RBAC) ensures the limitation of every user’s capabilities according to the set of roles and permissions assigned to them. Moreover, with the combination of detailed logs and RBAC, every change to the system can be traced back precisely to the accountable user and the point in time of the event.
What does centralized fleet management of virtual PLC look like in practice?
All major workflows can be executed from a centralized, cloud-native user interface. Role-based access control allows for built-in charts of authority to always maintain control over every actor in the system and their assigned permissions.

Virtual PLC fleet management starts with the setup and deployment of a topology of devices and services. Some of these services will need careful consideration and configuration, like the allocation of runtimes to physical hardware. Others can be configured fully automated, like the distribution of pub-sub data servers, ensuring seamless data flow throughout your automation stack.
Once deployed and operational, the same topology overview can serve as a high-level status and system health dashboard, highlighting available updates, connection or resource consumption alerts, or access to detailed logs for troubleshooting.
Updates to the control logic itself become significantly easier as well. While the PLC programs are managed and version controlled centrally, they can be rolled out in bulk updates to the field.
When it comes to the capabilities and functionality of such a cloud platform for PLC operations, here as well a few crucial building blocks are needed. A PLC integrated development environment (IDE) based on the international standard for PLC programming is the basis for creating and deploying high-performance control logic.
Combined with a powerful code versioning engine, engineers stay in control over the status and history of their deployments, closing the loop between the code pushed from the platform and the version and status reported back from the fleet of virtual PLCs in the field. With these platform cornerstones in place and in conjunction with the above-mentioned virtual PLC technology and its benefits, it is a small step to wrap it all up in a graphical and intuitive work process that lets engineers set up a topology of hardware devices and virtual PLCs, mass-deploy and update control logic and maintain and troubleshoot the entire system’s health: or in short, to achieve efficient PLC fleet management.
Real-world use case benefiting from Virtual PLC
One of our customers in the district heating industry operates a network with over a thousand substations, each equipped with a PLC that controls a heat exchanger unit connecting the distribution grid to end customers' local circuits.
A sizable team of engineers is responsible for the maintenance and development of this PLC fleet. In reality, however, the team is dedicating its entire time to maintenance only, and none to creating additional value through development and enhancements. The reason lies within the inefficiency of managing PLCs at scale. Although most of their facilities allow for remote updates, engineers still need to go through the cumbersome process of matching software with hardware versions and bridging gaps and differences in vendor-specific communication protocols (for historical reasons, at least two different brands of PLCs were deployed, and various models).
Rolling out OTee’s virtual PLCs to their substations and moving the entire PLC operations work process to OTee’s IIoT cloud platform, the engineering team can now bulk-update their virtual PLCs, capitalizing on the similarity of their substations' configuration and the instant response of their actions through the system’s decentralized pub-sub data framework. For the first time, the maintenance and development team can free up enough time to get to the fun part of their job description: developing, optimizing, and innovating.
You can learn more about the application of virtual PLCs in district heating through this link: District Heating Use Case: Boosting Operational Efficiency
Conclusion: Transition to managing centralized Virtual PLCs for greater efficiency over multi-vendor PLC fleets!
The complexity of managing a fleet of PLCs grows exponentially as systems scale, and the challenges don’t just come from the technology itself, they stem from the layers of inefficiency built into traditional approaches. Matching tools and hardware, managing disparate versions, and troubleshooting across multiple vendors can leave engineers spending more time on maintenance than innovation.
This is where virtual PLCs introduce a shift, not just in technology but in methodology. By decoupling control logic from hardware, a virtual PLC makes it possible to approach PLC operations with the same efficiency and agility we’ve come to expect in modern software systems. Bulk updates can be managed without the risk of mismatched configurations. Real-time diagnostics and centralized version control ensure that you always know the state of your system, eliminating the guesswork that often leads to downtime or inefficiencies.
At the center of this transformation should be a focus on interoperability and simplicity. Open architectures allow systems to work together seamlessly, breaking down the silos that have historically defined industrial automation. This approach doesn’t just solve immediate problems; it lays the foundation for long-term scalability and adaptability.
At OTee, we simplify and strengthen PLC operations, not by adding more complexity, but by finding smarter and more efficient solutions. For those navigating the complexities of automation systems, virtual PLCs are a tool worth exploring, as a step toward making their operations more efficient and routine tasks faster and automated.
What’s the next Step?
Real success with the virtual PLC comes from a deeper understanding of how these systems interact, how updates propagate across a fleet, how data flows securely, and how everything integrates into a centralized, intuitive workflow.
With OTee’s Virtual PLC and cloud-native platform, you can streamline updates, ensure system-wide compatibility, and gain real-time insights into your automation systems, all while breaking free from vendor lock-in. Whether you’re dealing with diverse hardware, scaling operations, or simply tired of inefficiencies slowing down your team, we provide the tools to make automation smarter, faster, and more reliable.
Experience it yourself
Book a demo today, or get started for free and discover how effortless managing a diverse fleet can be. Both options come with no obligations or hidden requirements.
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