In intralogistics, there are systems that everyone is familiar with. They’ve been running for 15, 20, or even 30 years, have transported countless orders, and have likely outlasted more product generations than many employees. Their steel structures are robust, their conveyor systems are well-established, and even unusual operating conditions barely faze them. There’s just one thing these systems don’t necessarily have: a control system that can still keep up with today’s IT landscape.
At the latest when spare parts become scarce, manufacturers discontinue support, or connecting to modern systems becomes a challenge, the seemingly simple question arises: Build new or modernize?
The intuitive answer is often: If the system is old, it has to go eventually. In practice, however, it’s worth taking a closer look. This is because, especially with long-lasting intralogistics systems, the real value often still lies in the mechanics, the infrastructure, and the process knowledge that has grown over the years. A targeted retrofit can therefore be an alternative to a complete rebuild—and turn a technically outdated system back into a reliable platform for the coming years of operation.
When the mechanics still work, but the control system no longer does
The typical retrofit scenario can be observed in many variations: The conveyor system generally operates reliably, the stacker cranes are still in good mechanical condition, or the sorting system continues to fulfill its purpose. The problem, however, lies with individual components of the automation and information technology.
A PLC from the 1990s or early 2000s, for example, may still perform its duties reliably. At the same time, it can become difficult to source suitable components or to resolve a failure on short notice. The same applies to drive controllers, operator panels, industrial PCs, fieldbus components, or network hardware. What was once state-of-the-art becomes an operational risk as soon as replacement parts have to be sourced from the second-hand market or the necessary expertise is no longer available from the original manufacturer.
This is exactly where a retrofit comes in. Instead of replacing the entire system, the first step is to analyze which components actually need to be modernized and which can still be used effectively. The result might be, for example, the replacement of the PLC and drive technology, while conveyor systems, steel structures, and other mechanical components are retained.
It is not the age of a system that determines its future viability, but its technical and economic condition.
This distinction is crucial. After all, there is a significant difference between “old” and “obsolete.”
A retrofit means more than just replacing a PLC
Anyone who thinks of a retrofit solely in terms of a new control system is missing the bigger picture. A modern retrofit views the system as a whole and focuses in particular on the interfaces between mechanics, automation, and IT.
This perspective is particularly important in intralogistics. A conveyor system does not operate in isolation. It is interconnected with inventory management, warehouse control systems, material flow computers, production systems, ERP solutions, and other applications. Therefore, when individual components are modernized, the communication paths and responsibilities between the systems must also be taken into account.
A retrofit can include the following areas, among others:
- Replacement of outdated PLC systems and decentralized peripherals
- Modernization of frequency inverters, motors, and drive controllers
- Replacement of old fieldbus and network structures
- Retrofitting with modern sensor technology
- Upgrading of operator interface and visualization systems
- Integration of a current WCS or modern material flow control system
- Connection to existing or new WMS and ERP systems
- Implementation of additional diagnostic and monitoring functions
- Collection of relevant operational and status data
- Modernization of safety-critical components
- Preparation for condition-based and predictive maintenance
This transforms a simple “component replacement” into a modernization of the entire technical architecture.
The major advantage of an existing facility: The material flow is already known
A new construction project offers maximum design freedom. At the same time, with a new system, many things must first be proven. Layouts are planned, simulations are created, components are selected, software is developed, and interfaces are tested. Only in actual operation does it become clear whether the system actually works as intended on paper.
An existing system, on the other hand, brings something that is difficult to buy: know-how gained from ongoing operation.
You know which conveyor lines are under particularly heavy load, where malfunctions tend to occur, which sensors are sensitive, and which processes generate especially high loads at certain times of the day. In many cases, employees know the system’s specifics better than any manual.
This knowledge is extremely valuable for a retrofit. It allows you to consider not only the documented target state but also the reality of the material flow.
This is precisely why a retrofit should not begin with the question of which new control system should be installed. The first step should be a systematic assessment: Which components are present? How do they communicate with one another? What dependencies exist? Where are the actual bottlenecks? Which components are critical? And which functions are truly needed during ongoing operations?
Only from this analysis can a sensible modernization strategy be developed.
The WMS stays, the WCS is modernized—or vice versa
Retrofitting becomes particularly interesting when the automation layer and the higher-level IT have aged at different rates.
For example, a WMS may still fully meet current requirements, while the underlying WCS or material flow control system has reached its technological limits. Conversely, the control level may have been modernized, while outdated warehouse management software fails to take full advantage of the new technology’s capabilities.
The challenge lies in clearly separating the systems from one another while simultaneously integrating them in a meaningful way.
A modern retrofit should therefore not only ask, which hardware is being replaced, but also which functions should reside at which system level. Where does the WMS’s responsibility end?
What tasks does the WCS handle? What logic belongs in the PLC? What information needs to be exchanged between the levels?
These questions are already part of the architectural planning for a new installation. In a retrofit, they are often added to an existing system landscape that has evolved over the years. This is precisely why clear interfaces and thorough documentation are particularly important.
An Old System Becomes a Data Source
One of the most interesting developments in modern retrofit projects is the ability to extract additional information from existing systems.
While many older systems have numerous sensors and status data, they primarily use this information for immediate plant control. For example, a sensor detects the presence of material being conveyed. A motor is running or stopped. An alarm is triggered. A temperature is monitored.
Modern automation architectures can do much more with this data.
Operational data can be collected, archived, and linked to other information. This creates new opportunities for analysis and optimization. How often does a specific conveyor section fail? Which components cause the most downtime? How does the performance of a conveyor line change throughout the day? Where do delays occur in the material flow?
This shifts the role of the system. It no longer merely transports goods but simultaneously provides information about its own condition.
This is particularly interesting for companies that want to gradually transition toward data-driven intralogistics. Not every system needs to be completely rebuilt for this.
Predictive Maintenance Doesn’t Start with Artificial Intelligence
When it comes to modern equipment, the term “predictive maintenance” quickly comes to mind. In fact, a retrofit can lay a solid foundation for this—but not by simply installing as many sensors as possible and then waiting for a miracle diagnosis.
What matters most is relevant data and its meaningful interpretation.
Increased current draw in a motor, unusual vibrations, or rising temperatures can indicate a changing operating condition. If such information is systematically recorded, maintenance strategies can be gradually developed from purely time-based intervals toward a more condition-based approach.
The first step in this process is surprisingly unspectacular: The system must first be able to digitally describe its own condition.
It is precisely this capability that can be specifically retrofitted. Sensors, diagnostic functions, communication interfaces, and data acquisition can be integrated into the modernization without having to replace the entire conveyor system or the entire warehouse.
A retrofit does not automatically eliminate every risk
As attractive as modernizing existing systems may be, a realistic risk assessment is just as important. An old system is full of unique features that have evolved over time. Over the years, components have been replaced, software adapted, sensors added, and functions modified. This evolutionary path is not always fully reflected in the existing documentation.
This can lead to surprises during modernization.
That is why a comprehensive inventory is one of the most important phases of a retrofit project.
Circuit diagrams, software versions, network topology, drives, sensors, safety functions, and interfaces should be documented as completely as possible. Equally important is the question of which components will remain critical after the retrofit.
After all, a new control system alone does not solve a spare parts problem if, ten years later, another old component becomes a bottleneck.
A good retrofit therefore thinks at least one technological step ahead.
The Art Lies in Finding the Right Balance
Technically, an old system can sometimes be modernized to an astonishing degree. However, not every technically feasible measure is necessarily economically viable.
That is why a retrofit should always consider multiple dimensions: investment costs, remaining service life, performance, availability, spare parts strategy, energy consumption, maintenance requirements, and future expandability.
The planned operating life also plays a role. Is the system supposed to be operated for another five years? Ten years? Or is it intended to remain part of the logistics strategy for another 15 years?
This question significantly changes the requirements for modernization.
If the remaining service life is short, a targeted replacement of critical components may be sufficient. From a long-term perspective, a more comprehensive redesign of the control and communication layers may be worthwhile.
Retrofit is therefore less a single technology than a strategic decision regarding a system’s lifecycle.
Modernize step by step instead of turning everything upside down at once
Another advantage is that, under the right conditions, modernization projects can be implemented in a modular fashion.
This is particularly relevant in intralogistics. A central warehouse cannot simply be shut down for weeks just because the control system is being replaced. Any prolonged interruption has a direct impact on production, shipping, and delivery capabilities.
That’s why retrofit concepts that minimize downtime as much as possible are in demand. Depending on the facility, preparatory work can be carried out outside of operating hours, new components can be installed in parallel, and individual sections can be converted one after another.
A phased migration of the software can also be beneficial. Existing functions are first retained, then gradually modernized and expanded.
This requires detailed planning and cannot be applied uniformly to every system. But it is precisely this flexibility that makes retrofitting attractive to many operators: Modernization can be tailored to day-to-day operations, rather than requiring operations to be completely reorganized around the modernization process.
Sustainability sometimes begins with reuse
In addition to technical and economic considerations, the issue of resource use is increasingly taking center stage.
Building a completely new system means more than just new hardware. Existing components must be dismantled, transported, and disposed of. At the same time, the new system requires significant amounts of materials and energy.
With a retrofit, on the other hand, the first step is to assess which components can be reused. Steel structures, conveyor lines, roller conveyors, mechanical components, or other system parts do not automatically need to be replaced simply because the control system is being modernized.
This does not automatically make a retrofit a more sustainable solution. The energy consumption of outdated mechanical systems, the efficiency of drives, maintenance requirements, and the remaining service life must also be taken into account.
But the basic idea is compelling: Why replace a technically serviceable component if it can still serve its purpose for many years to come?
When a New Build Is the Better Option
Despite all the advantages, there are clear situations in which a new build may make more sense.
When the mechanical system has reached the end of its economic service life, when the desired performance can no longer be achieved with the existing structure, or when essential safety and efficiency requirements can only be met at disproportionate cost, retrofitting reaches its limits.
Fundamental changes to the business model can also make a new construction necessary. A warehouse that was originally designed for specific product structures and order volumes cannot be arbitrarily adapted to completely different requirements.
The crucial question is therefore not “Retrofit is better than new construction,” but rather:
Which option offers the more sensible long-term outlook given the specific technical, economic, and operational conditions?
This requires a robust analysis—and sometimes the conclusion is indeed: new construction.
Looking Ahead to the Next Ten Years
Retrofitting becomes particularly interesting when modernization is not viewed as a short-term fix.
Anyone modernizing an old facility today should already be considering what requirements might arise in five or ten years. Will additional storage areas be needed? Will capacity need to be increased? Should the facility operate in a more data-driven manner? Which IT systems could be integrated in the future? How easily can additional sensors or automation components be integrated?
A modern architecture should at least take these questions into account.
This doesn’t mean incorporating every conceivable future function today. Rather, it means creating the conditions necessary for the system to be expanded later on without once again facing a technological dead end.
This also changes the objective of a retrofit: It’s not about artificially keeping an old system alive for as long as possible. It’s about combining its existing infrastructure with a future-proof technical architecture.
Even the oldest plant can suddenly become interesting again
Perhaps this is the most surprising insight: A plant with 20 or 25 years of operational experience doesn’t have to be a problem for the company.
If the mechanics and infrastructure are still reliable, the processes are functioning, and the system has a solid foundation, its age can actually be a reason to modernize it. This is because a retrofit makes it possible to preserve what has been proven effective while simultaneously making changes where requirements have changed.
An old PLC becomes a modern control platform. Individual sensor readings become usable operational data. An isolated system becomes an integrated part of the IT landscape. Reactive maintenance can evolve into a more condition-based strategy.
And a system that may already be referred to internally as a “vintage machine” becomes once again a productive member of modern intralogistics.
Conclusion: Future-readiness is not a matter of the year of manufacture
The decision between a retrofit and a new build should not be based on the age of a system. What matters is the technical condition of the system, which weaknesses need to be addressed, and what requirements the intralogistics system must meet in the future.
Especially in material handling and automation, a targeted retrofit can offer significant potential. Control systems, drives, sensors, networks, and software can be modernized while proven mechanical components continue to be used. At the same time, modern interfaces, data structures, and diagnostic functions can be created that bring an existing system significantly closer to today’s digital system landscape.
However, this requires more than just replacing individual hardware components.
Successful retrofit projects begin with a thorough assessment of the current state, a clear target architecture, and an understanding of how the system is actually operated.
After all, ultimately, it’s not about making an old system look newer.
It’s about giving it a future.
And sometimes, that is precisely what is more economical, more sustainable, and technically more sensible than starting from scratch.
More interesting articles on retrofitting as well as reports on our retrofit projects:
Four perspectives on the ultra-modern multi-channel warehouse WDZ Sachsenheim
TUP Defines “Permanent Retrofit” as a Guiding Principle for the WMS of the Future
Retrofit par excellence: TUP modernizes material flow control at Hermes shipping center
Minimum viable change as a compass for successful retrofits and greenfield projects
Major WMS Retrofit Project Successfully Completed—With TUP and the Rotary Dial Principle
