Control System Upgrades: A Strategic Investment in Line Longevity

A production line’s control system ages much faster than its mechanical components. This gap exists because electronic hardware and software reach the end of their useful life long before sturdy mechanical elements wear out. Periodic control system upgrades are therefore a necessary element of long-term line maintenance for most high-duty production lines. Timely modernization keeps uptime high and ensures the line can adopt new automation, data analytics and diagnostics, and security capabilities.

By Patti Engineering CEO Sam Hoff

Control systems serve as the operational core of a manufacturing production line. They synchronize equipment, execute process logic, monitor system conditions, and interface with supervisory platforms. As these systems age, they introduce operational challenges that reduce uptime, limit productivity and efficiency, and increase cybersecurity risk.

While earlier articles have discussed the reasons to consider a control system upgrade, the strategies for its successful execution, and the use of virtual commissioning tools with a phased approach for complex upgrade projects, this article focuses on a more fundamental question:

Why do control systems become liabilities long before the line’s mechanical equipment reaches the end of its service life?

The answer lies in the foundational differences between control system components and the mechanical elements of industrial production lines. In fact, because they age so much faster, periodic control system upgrades should be considered a part of a high-duty production line’s long-term maintenance plan.

Figure 1: Typical lifespan ranges for common industrial mechanical and control system components. Values reflect general industry experience and typical operating expectations. 

Failure and Obsolescence: How Control Systems Become Operational Risks

A control system is an industrial computer built from modular components including CPUs, I/O cards, power supplies, and communication interfaces. These modules are comprised of circuit boards populated with microchips, discrete electronic components, conductive traces and electrical connectors.

Over time, these systems both degrade and become obsolete because electronic parts wear out and computing technology advances rapidly. While degradation can be mitigated, it remains unavoidable and occurs far sooner for electronics-based assemblies than mechanical equipment, primarily because the components are much smaller and therefore more sensitive to stressors (see figure 1).

The following sections further explain the issues manufacturers face due to control system electronics’ degradation and obsolescence.

Electronics Degradation

The electronic components inside PLCs, HMIs, and drive units degrade due to harsh environmental conditions, near continuous operation, and operating demands that push them toward their electrical, thermal, and mechanical limits. Temperature fluctuation, humidity, dust, vibration and electrical noise all contribute to increased component failures. These faults are often difficult to diagnose because they may happen intermittently within devices’ circuit boards and internal assemblies.

Common failure mechanisms include:

• Solder joints that develop micro-cracks due to vibration and thermal cycling, leading to intermittent connectivity.
• Capacitor dielectrics that dry out, reducing charge storage capacity and increasing the risk of circuit malfunction.
• Connector pins that corrode or loosen, resulting in intermittent connectivity loss.

While most industrial controls manufacturers incorporate robust design features to mitigate these stressors, long-term degradation remains inevitable. Failures often emerge after 10 to 15 years, depending on duty cycle and cabinet conditions.

On the production line, these failures typically cause intermittent faults including sporadic machine stoppages, unexpected resets, communication errors between devices, loss of I/O signals, or inconsistent sensor readings.

Protect Control Systems with Proper Enclosures

Enclosures that lack adequate cooling, filtration, or sealing lead to premature failure of electronic components. Manufacturers can extend the life of their control systems by installing them in well-designed enclosures that provide:

• HVAC or active cooling to manage heat buildup
• Air filtration to reduce dust accumulation
• Proper environmental sealing with the correct IP or NEMA rating for the application

Regular enclosure inspection and maintenance is also important for ensuring long-term protection.

Discontinuation of Spare Parts Support

As control system components age, internal degradation eventually leads to persistent failures. When critical modules begin to fail consistently, replacement parts must be obtained to restore production.

Most OEMs offer spare parts support for 10 to 15 years after a product’s final production date. Beyond this point, spare parts support is phased out and sourcing them becomes increasingly difficult and expensive. Commonly needed spares include batteries, power supply modules, processor modules, I/O cards, communication cards and HMI displays.

Even when parts remain officially supported, long lead times are common. Depending on the part and vendor, lead times for processor modules, I/O cards, and HMIs can extend to several months, increasing the risk of prolonged downtime when critical modules fail.

OEM discontinuation of product support affects more than just access to replacement parts. It also impacts necessary firmware updates and support for software development platforms.

Discontinuation of Firmware Updates

During the active support phase of a product, electronics OEMs release periodic updates to their product’s internal software, known as firmware, to address lingering bugs, new security gaps, and general performance improvements.

Typically, five to ten years after a product’s discontinuation, OEMs of industrial control systems cease further firmware support. From this point onwards, any bugs or new cybersecurity vulnerabilities will not be fixed, leaving those who continue to operate these systems exposed.

A major example occurred in 2021, when a critical vulnerability was discovered in several Rockwell Automation Logix controllers. The issue allowed attackers to bypass authentication protections and potentially take control of affected PLCs. While Rockwell Automation released firmware updates to fix the issue for some models, older controllers that were no longer supported did not receive the patches. This vulnerability prompted urgent advisories from cybersecurity agencies.

Discontinuation of Software Environment Support

Similar to discontinuation of firmware support, vendors also eventually stop supporting legacy programming environments.  Over time, a PLC’s programming software may only run on obsolete operating systems (e.g. Windows XP), making it difficult to update system logic, integrate new equipment, or adjust process sequencing.

A well-known example of the risks associated with outdated operating systems involves the continued use of Windows XP in industrial environments, despite Microsoft having ended support for it in 2014. In 2017, the WannaCry ransomware attack was released, exploiting vulnerabilities in unpatched Windows systems, including Windows XP.  Within the industrial manufacturing sector, this attack impacted Renault-Nissan in 2017, who was forced to temporarily halt production at several manufacturing plants due to widespread disruptions.

Today, many facilities still rely on Windows XP-based systems because critical software tools, including older versions of RSLogix 5000, Siemens Step 7, and Wonderware InTouch, were originally certified for it.

While upgrading the control system is a strong approach to improving cybersecurity, it should be noted that outdated systems can still be protected by implementing industrial cybersecurity standards and best practices, including ISA/IEC 62443 and NIST 800-82.

CPU Obsolescence

Advancements in computing technology have been tremendous over the past several decades, leaving older systems incapable of supporting modern manufacturing requirements.

Legacy processors lack the speed, memory capacity and architecture to support modern automation, limiting manufacturers’ ability to integrate advanced technologies.

For example:

• Slow scan times limit cycle times and overall system responsiveness.
• Legacy CPUs often lack the resources for today’s high-speed servo or multi-axis motion tasks.
• Insufficient memory and processing speed prevent real-time data collection for OEE tracking, digital twin implementation, data analytics applications, and quality monitoring.

In addition to processing limitations, older control systems also face communication challenges that hinder integration with modern industrial networks.

Communication Obsolescence

Older PLCs do not support modern communication standards including EtherNet/IP, PROFINET, or OPC UA, resulting in difficult integration with newer drives, safety systems, SCADA platforms, and MES environments. While protocol converters can bridge the gap, they introduce complexity and additional latency.

For manufacturers, this results in limited system scalability, higher integration costs, and difficulty implementing plant-wide data sharing or centralized control strategies.

Closing Remarks

Industrial electronics-based devices inevitably age faster than their mechanical counterparts, but this does not have to threaten production. In reality, a control system upgrade is a necessary part of maintaining a production line to avoid associated failures, downtime, and security risks.

Control system modernization addresses the problems associated with legacy lines, and results in clear operational benefits:

• Improved reliability through updated hardware and restored access to spare‑parts
• Stronger cybersecurity posture with supported firmware and development environments
• Greater capability for data analytics, digital twins, high‑speed motion, and plant‑wide connectivity

When viewed strategically, control system upgrades shift from a reactive cost to an important investment that keeps the line productive, secure, and ready for tomorrow’s automation demands.