Industrial Automation · PLC · System Reliability · Failure Analysis
Types of Failures in Industrial Automation Systems: 8 Costly Risks Every Engineer Must Know
Automation is built to reduce mistakes, yet the systems that automate a plant can fail in their own specific ways. This guide explains the types of failures in industrial automation systems in plain words, groups them into clear categories, and gives you a simple risk score calculator.
Why Automation Systems Still Fail
Industrial automation is meant to save manpower, speed up production, and make results more consistent. But an automated system is still built from people, code, wires, and hardware, and each of those pieces can fail in its own way. Since these systems often run critical processes, a failure here rarely stays small for long.
Understanding the different failure categories helps engineers catch problems earlier and design more resilient systems, whether that means better PLC redundancy or a properly sized backup power supply. Most failures fall into a few repeatable patterns once you know what to look for.
How a Small Failure Becomes a Big Problem: 4 Steps
A mistake, a worn part, or a weak connection quietly develops somewhere in the system.
→Without proper testing, monitoring, or alarms, the developing issue is not noticed right away.
→A value stops updating, an output stays stuck, or a screen becomes unresponsive.
→By the time the problem is visible, it has often already cost time, money, or safety margin.
8 Types of Failures in Industrial Automation Systems
Each of these eight types has its own root cause, its own warning signs, and its own way to prevent it. Understanding all the types of failures in industrial automation together, rather than just the common ones, makes it much easier to recognize which one is actually happening on your line.
The most common cause of failure in any system, often linked to fatigue, stress, or a lack of clear training and checklists.
Typical cause: confusing HMI design, missing SOPs, tired or undertrained operators.
A bug, an incorrect setting, or logic that was never designed for long term or edge case values.
Typical cause: a counter or limit set too low, logic missed during commissioning tests.
A PLC, HMI, VFD, or any physical automation component wearing out or being damaged by harsh conditions.
Typical cause: electrical noise, voltage spikes, poor earthing, physical damage.
Automation systems depend heavily on switches, cables, and communication links to move data reliably.
Typical cause: power outages, poor cable quality, or security gaps allowing cyber attacks.
A valve, sensor, or actuator out in the process that stops measuring or acting correctly due to wear, corrosion, or physical damage.
Typical cause: harsh process conditions, missed calibration, corrosive or dirty media.
Damage inside the enclosure that houses the controller itself, separate from failures out in the field.
Typical cause: voltage spikes, poor earthing, overheating inside the panel, moisture ingress.
Gradual component degradation that builds up over years of normal use, rather than appearing suddenly.
Typical cause: components running past their expected service life, weak maintenance tracking.
An unresponsive, frozen, or malfunctioning HMI screen that leaves the operator unable to reach critical controls when it matters most.
Typical cause: software bugs, memory overload, outdated HMI hardware.
Grouping the Failure Types by Root Cause
Detection Difficulty and Prevention by Failure Type
| Failure Type | Detection Difficulty | Main Prevention Method |
|---|---|---|
| Human error | Moderate | Training, clear SOPs, better HMI design |
| Programming error | High, often hidden until triggered | Thorough testing, edge case review |
| Hardware failure | Low to moderate | Spare parts stock, proper environment |
| Network failure | Moderate | Quality cabling, redundant links, cyber security |
| Field instrument failure | Moderate | Calibration schedule, physical protection |
| PLC panel failure | Low | Proper earthing, surge protection, enclosure rating |
| Age based failure | Low, if tracked properly | Lifetime tracking, planned replacement |
| Graphics failure | Low, but disruptive when it happens | Screen maintenance, backup HMI access |
Where Each Failure Type Usually Shows Up
Human error is most common here, driven by stress or unclear procedures.
Programming errors are usually created here, well before commissioning.
Field instrument and hardware failures often surface at these connection points.
Network failures usually trace back to this layer of the system.
PLC panel failures are contained here, often needing a vendor visit to resolve.
Age based failure and graphics failure both build up here over years of use.
Reducing Failure Risk in Automation Systems
- Provide clear operator training and SOPs: to reduce the most common failure type before it happens.
- Test PLC programs against edge cases: not just normal operating conditions, before commissioning.
- Keep critical spare parts in stock: so a hardware failure does not turn into extended downtime.
- Track component age and maintenance history: so age based failure can be planned for, not discovered.
- Don't skip commissioning tests for counters and limits: unhandled overflow conditions are a classic programming error.
- Don't ignore small network latency issues: they often signal a larger network failure building up.
- Don't dismiss graphics or HMI glitches as minor: they can leave an operator unable to act during a real event.
- Don't delay replacing aging components: just because they still technically work today.
Failure Risk Score Calculator
Select a likelihood and impact rating to calculate a simple risk score for any failure type.
Quick FAQs: Types of Failures in Industrial Automation
External References
- IEC 61508: Functional Safety of Programmable Electronic Systems
- ISA: Automation System Reliability Resources
- Wikipedia: Reliability Engineering
What we learn today
- Types of failures in industrial automation systems fall into eight repeatable categories, from human error to graphics failure.
- These failures broadly group into people and process, technology and equipment, and wear and interface related causes.
- A simple risk score, likelihood multiplied by impact, helps teams decide which failure types deserve attention first.
- Good training, thorough testing, spare parts planning, and proactive maintenance address most of these failure types before they become costly.