Control System Obsolescence: What Are the Risks?

Control systems 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).

As control systems age, they introduce operational challenges that reduce uptime, limit productivity and efficiency, and increase cybersecurity risk, making periodic control system upgrades a necessary element of long-term line maintenance. Timely modernization keeps uptime high, ensures the line can adopt new automation, data analytics, and diagnostics, and enhances the system’s security capabilities.

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

The Consequences of Control System 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.

Where Do Electronic Components Fail the Most?

• 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.

What Failure Looks Like

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.

No Product Support or Replacement Parts

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 replacement parts can extend to several months, increasing the risk of prolonged downtime when critical modules fail.

Discontinuation of Firmware Updates

OEM discontinuation also impacts necessary firmware updates and support for software development platforms.

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

Typically, 5 to 10 years after a product’s discontinuation, OEMs cease further firmware support. From this point onwards, any bugs or new cybersecurity vulnerabilities won’t be fixed, leaving those who continue to operate these systems exposed.

A significant 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.

Discontinuation of Software Environment Support

Over time, a PLC’s programming software may only run on obsolete operating systems, making it difficult to update system logic, integrate new equipment, or adjust process sequencing. 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.

A well-known example of the risks associated with running outdated operating systems is the release of the WannaCry ransomware attack, which exploited 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.

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.

Slow CPUs

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 face communication challenges that hinder integration with modern industrial networks.

Integration and Scalability Challenges

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.

Is It Time to Update Your Control System?

Control system obsolescence does not have to threaten production. Modernizing your system addresses the problems associated with legacy lines, and results:

• 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.

If you’re not sure if your control system is ready for an upgrade, please visit Part 1 of our Control System Upgrade guide.

Whether you’re considering modernizing your control system now or later on down the road, Patti Engineering can help. Founded in 1991, we’re a multidisciplinary engineering consulting firm specializing in control systems integration and Industry 4.0 digital transformation. Visit our website to learn more about our capabilities, or contact us if you’re ready to schedule a consultation.

FAQs

What Is Control System Obsolescence?

Control system obsolescence refers to the process of the electronic components within a control system aging out.

What Is the Lifespan of Electronic Components?

Lifespans vary. Electronic components have a shorter lifespan compared to mechanical components. For example, tanks and piping can last for up to 40 years if well-maintained, while electronic components like VFDs and PLCs only last for around 15 years. Other technologies, like sensors, frequently evolve, so they may become obsolete in as little as five years.

Which Components in a Control System Often Fail First?

Connector pins, capacitor dielectrics, batteries, power supply modules, processor modules, I/O cards, communication cards, and HMI displays.

What Can Happen When Control Systems Age?

There are many risks associated with an aging control system, including:

• Circuit malfunctions
• Intermittent connectivity loss
• Unexpected resets and stoppages
• Communication errors between devices
• I/O signal loss
• Inconsistent sensor readings
• Security vulnerabilities
• Slow system response

How Long Does It Take for OEMs to Phase Out Product Support?

It depends on the product. For replacement parts, support typically ends around 15 years after the final production date. For firmware, support generally ends 10 years after discontinuation.

Why Is Control System Obsolescence a Security Risk?

OEMs will stop supporting firmware and software, meaning that no updates will be run to address bugs and close security gaps.

Why Is It Hard to Scale a Legacy System?

Many legacy systems don’t support modern communication standards, making it more challenging to implement newer components.