Programmable Electronic Devices: A Comparative Analysis of Standard PLCs and Purpose-Built Controls


In the realm of industrial automation and control, programmable electronic devices have become integral to the orchestration of both machinery and processes.

At the heart of this landscape, we can find:

  • standard Programmable Logic Controllers, known as PLCs
  • purpose-built Electronic Controls

Each comes with its distinct advantages and applications.

As developers and manufacturers of customised electronic controls, we are well-versed in the nuances and capabilities that these systems bring to the table. We'll be very transparent about this: our experience has shown time and again that while PLCs offer a generalised solution suitable for a wide range of applications, purpose-built, or bespoke, electronic controls are engineered to meet the specific needs of an application and therefore they lead to an overall greater efficiency and a tailored fit for any industrial tasks.

Our focus on the development of purpose-built controls stems from a deep understanding of the unique challenges that specialised applications can present.

Standard PLCs, while versatile and widely adopted, can sometimes be limited by their generic design and programming, which may not optimally align with the intricacies of every process.

On the other hand, purpose-built electronic controls benefit from custom design and functionality that directly address the User’s specific requirements, often resulting in improved performance and ease of integration into existing systems.

Through our involvement in the creation of bespoke control solutions, we've observed that they frequently outperform generic PLCs in terms of both precision and reliability within their intended environment. The benefits of a tailored approach include not only the potential for increased operational efficiency but also the advantage of having control technologies that are inherently adaptable to the evolving needs of the industry. It is our assertion that in many situations, purpose-built controls offer a higher value proposition, providing a key competitive edge for businesses seeking to optimise their processes, systems and experiences for better outcomes.

Let's dive deeper into PLCs for a moment.

Fundamentals of Programmable Logic Controllers (PLCs)

PLC for industrial automation

Programmable Logic Controllers, commonly known as PLCs, are robust industrial electronic devices built for automating various processes, machines and systems. At their core, PLCs comprise a processor or a central processing unit (CPU) that executes control instructions based on the inputs received and the predefined programming logic.

The inputs to a PLC are electrical signals originating from sensors or manual switches, revealing the current state of a machine or process. These inputs are crucial for reactivity and response. The outputs, instead, are also electrical signals but they are sent from the PLC to activate actuators or indicators, directly influencing the controlled process.

A notable characteristic of PLCs is the use of a programming device and specific programming languages. The most prevalent of these is ladder logic, a language that simulates relay logic and is particularly user-friendly for engineers and technicians familiar with electrical circuit diagrams.

PLCs are programmed via software on a computer or handheld programmer. This programming governs the logic functions the PLC will execute, including but not limited to sequencing, timing, counting, and arithmetic computations. This flexibility enables to adapt PLCs for a wide array of applications, ensuring they can meet complex needs of control systems where a purpose-built device may not always be necessary or optimal.

In terms of structure, a PLC can be composed of a single unit or be modular, allowing for expansion and adaptation. This modular design benefits Users by providing the ability to scale and customise the PLC according to specific requirements, without the need for a complete system overhaul.

Now, let's focus on custom electronic controls instead.

Overview of Purpose-Built Electronic Controls

Lab for the development and design of dedicated electronic controls

Within the landscape of automation systems, we specialise in crafting purpose-built electronic controls that address specific industrial requirements. Unlike standard Programmable Logic Controllers (PLCs), these custom-designed solutions are tailored to integrate seamlessly with both input and output devices no matter their scope or nature, ensuring efficient operation and a sky-high degree of flexibility.

Here's a list of key aspects that will help you appreciate immediately the difference between a PLC and a Custom Electronic Control.

Key Aspects:

  1. Customisation: Our electronic controls are developed with the Client's unique needs in mind. This bespoke approach allows for fine-tuning to intricate system specifications.
  2. Integration: As a computing device central to the automation control, it is designed to effortlessly communicate with a wide array of sensors and actuators, adhering to stringent automation protocols.
  3. Optimisation: With efficiency as a cornerstone, these controls are programmed to optimise the performance of dedicated machinery and processes, utilising only very specific and measureable resources.
  4. Performance: Purpose-built controls are engineered for robustness and reliability, minimising downtime and enhancing the productivity of an automation system.

But that's not all, there are additional benefits.

Additional Benefits:

  • Unparalleled flexibility for future modifications and scalability
  • High precision in control system behaviour, leading to predictable and desired outcomes
  • Fully tailored UI and hyper distinctive design
  • Streamlined interface with industry-specific input and output devices

Employing purpose-built electronic controls ultimately signifies choosing a control system that is not only performant but also truly aligned with the unique features and specs of a given application. Our expertise ensures that we deliver solutions that are at the forefront of control technology, empowering Clients to leverage the true potential of their automation systems.

Comparative analysis of PLC and electronic controls

Evaluating and choosing between standard PLCs and specific electronic controls requires a comprehensive understanding of their differences in hardware, programming capabilities, application contexts and performance metrics.

Hardware features

Our controls are often designed with custom hardware tailored to specific needs. PLCs typically offer a standard modular approach , allowing for a range of AC or DC power supplies , transistor or triac outputs , and the installation of additional modules. In contrast, our designs allow the integration of multiple specific circuits into a single control, optimizing space and reducing the need for additional external components.

Software and programming

Software tools and programming languages ​​for PLCs are generally standardized across the industry, adhering to the IEC 61131 and IEC 61131-3 standards . They support a variety of simple programming paradigms such as Instruction List (IL) , Structured Text (ST) , Sequential Functional Framework (SFC) , Function Block Diagram (FBD), and Chain Diagram (LD) .

On the contrary, our electronic controls are programmed with efficient and scalable languages ​​close to the hardware, allowing precise, complete and detailed management of the machine. This type of programming provides dynamic logic, optimized for the intended industrial application, and guarantees a greater degree of safety and reliability.

Application scenarios

PLCs are versatile and can be used in a wide spectrum of industrial applications, from simple motor control to more complex production and assembly lines.

The dedicated controls, in turn, are designed for operational contexts where efficiency, precision and safety are essential.

Our controls also offer a modern and elegant user interface that can be tailor-made for our Customers, creating a better user experience and generating a significant and lasting competitive advantage.

Performance and efficiency

Regarding performance, standard PLCs have good reliability and robustness, but are less efficient and have longer reaction times due to their generic nature.

Customized electronic controls, on the other hand, are able to offer better performance, perfectly maximized efficiency levels and a use flow completely aligned with application needs.

At CTA, with a design focused on precise requirements, we ensure optimal reliability, addressing problems, contexts and variables more directly and efficiently than is possible with standard PLCs.

Hardware and software specifications

From a hardware point of view, we can say that both PLCs and custom electronic controls have the same structural skeleton on an empirical level:

  • Processor logic : CPU capable of processing complex logical operations
  • I/O modules : actuation modules that include digital and analog inputs/outputs
  • Communication protocols : Protocols such as Modbus and TCP-IP , which facilitate integration with a variety of devices and systems allowing for the secure exchange of data

The difference consists in the fact that a dedicated electronic control has hardware sized for specific needs, and consequently it is often also cheaper.

From a software point of view, we are in the presence of two completely different systems in terms of development environment, functionality and intrinsic safety.

Custom electronic controls offer significantly greater flexibility, as they are 100% programmable based on the specific needs of the project or application. These devices can be programmed using real programming languages, such as C, C++, Python or other industrial automation-specific languages, which can give developers the ability to implement complex algorithms, handle data in a sophisticated way and integrate with systems existing more smoothly and powerfully.

In contrast, standard PLCs are often associated with a more rigid development environment and a more limited set of programming tools, typically based on automation-specific languages, such as Ladder Logic, Function Block Diagram (FBD), or Structured Text (ST).

The complete programmability of custom electronic controls translates into greater capacity for customization and performance optimization. These systems can be adapted to meet very specific requirements, such as handling particular communication protocols, processing high-speed signals, or integrating with advanced technologies, such as artificial intelligence or machine learning. Furthermore, the ability to use standard programming languages ​​paves the way for greater integration with databases, web applications and other IT systems, thus providing a more scalable and connected solution.

In terms of intrinsic safety, the customization of custom electronic controls also allows the development of systems that are intrinsically safer, since they can be designed to mitigate specific risks related to the operating environment in which they will be used. For example, they can be configured to limit access to critical functions, monitor in real time any intrusion attempts or operational anomalies and implement automatic response protocols in the event of security events.

On the other hand, standard PLCs while generally robust and reliable, can be limited in their ability to adapt to emerging threats unless they are upgraded or integrated with external security modules. Their standardized nature can also make them a more predictable target for targeted attacks, making it critical to adopt rigorous security practices and careful vulnerability management.

Overall, our goal is always to provide optimal performance through dedicated hardware and software solutions, offering a safe, reliable and scalable alternative to traditional PLC systems.

Practical considerations

When choosing electronic controls for industrial processes, practical considerations must be taken into account.


Let's briefly explore the benefits of both types of devices.

  • Advantages of Standard PLCs :

    • Adaptable to a wide range of applications
    • Standardization facilitates compatibility between products from different vendors
  • Advantages of customized electronic controls :

    • Optimized to increase efficiency in specific tasks
    • Capable of providing optimal performance even in specialized contexts
    • They come ready to use and are generally cheaper than a generic PLC

Standard PLCs, despite their versatility, may not reach the level of specialization and optimization for specific tasks that is perfectly achievable with tailor-made control systems.

Maintenance and durability

While standard PLCs may offer a wider range of maintenance resources , we guarantee that our purpose-built controls are made from robust materials and are less prone to failure. They can often guarantee longer periods between maintenance interventions.

The safety aspect

Security is a fundamental pillar. The customized control systems we create are equipped with interlocks and tailor-made safety features, which integrate perfectly with the specific needs of the industrial process for which they are intended.

  • PLC Standard:

    • they come with standard security features
    • they have the possibility of expansion with additional safety modules
  • Customized Control Systems:

    • they contemplate the implementation of advanced security solutions, designed based on the application context
    • they allow the creation of operations regulated by ad hoc security measures

In essence, customized control systems can offer higher levels of safety than standard PLCs, thanks to harmonization with the specific safety requirements of the applications for which they are designed.

Historical evolution and development

In the world of programmable electronic devices , the technological journey began with basic controls based on relay logic. These hard-wired relay systems were standard in controlling manufacturing equipment. Their operation was basic, but effective for simple tasks. However, as automation has expanded, the limitations of relay-only controls in terms of complexity and flexibility have become apparent.

In the 1960s, General Motors' (GM) growing dissatisfaction with these complex and inflexible relay systems in assembly operations led to a search for an alternative. This need catalyzed the innovation of programmable logic control (PLC). Dick Morley is often considered the father of the PLC, as he introduced a design that revolutionized the industry thanks to its reprogrammability and robustness.

EraTechnological Development
1950s-60sWired relay controls dominate.
1968Introduction of the PLC by Dick Morley
From the 70s onwardsRapid development and diffusion of programmable logic controls in automation

PLCs represented a quantum leap, offering a standardized approach to industrial control systems. They made it easier to change control logic and reduced the downtime needed to retool equipment. The ability to use a simple, accessible programming language ushered in a new era of automation, where changes could be made quickly and without the need to alter physical wiring.

While standard PLCs offered a quantum leap over relay logic, an era of more customized solutions was ushered in with custom-built electronic controls . These devices outperform standard PLCs, enabling greater efficiency and a better user experience in industrial control systems.

In the development landscape of the sector, new technologies such as automatic learning or machine learning (ML) and artificial intelligence (AI) have recently begun to be introduced . These integrations equip controls with predictive maintenance capabilities and adaptive algorithms that improve performance over time. The idea of ​​self-optimizing systems is now becoming a reality even in the industrial sector, establishing a new standard of operational efficiency.

TrendDescriptionImpact on controls
Data processing at the point of collection for rapid response.Improve real-time control
AI by MLEnabling predictive and adaptive capabilities.Improves system efficiency.
IoT integrationExtended device connection for comprehensive control and data analysisExpanding the scope of control

Additionally, we are seeing significant development in modularity and broad-spectrum customization . The interoperable modules allow specific industrial needs to be promptly satisfied without necessarily having to overhaul the entire system. This modular approach ensures future adaptability and easier upgrades, and this scalability feature makes custom-built control devices even more advantageous.

Frequent questions

As specialists in the development and construction of custom electronic control systems, created ad hoc, we completely master even the smallest nuances that differentiate these systems from standard PLCs. Our experience in this industry gives us unique insight into the advantages, disadvantages and use cases of each control solution.

Below we answer the most frequently asked questions on the topic.

What distinguishes PLCs from normal commercial computers in terms of control capabilities?

PLCs are distinguished from normal commercial computers mainly by their control ability in industrial environments. Designed specifically to manage automation operations, PLCs - unlike commercial PCs - are optimized to collect data from sensors and implement commands on machinery and industrial processes.

How do PLCs compare to electronic controls specifically created for industrial environments?

PLCs represent a standard control system, robust but not particularly flexible or scalable. Overall, they provide a standardized platform that can be employed in a variety of industrial environments and applications.

Custom electronic controls, on the other hand, are designed and built to meet specific needs, offering tailor-made solutions that can be optimized to maximize efficiency and performance in complex operations or particular environmental conditions.

These customized systems can integrate advanced and specific functionality that goes beyond the capabilities of standard PLCs, thus providing an ideal solution for applications that require a higher level of specialization or a richer user experience.

In what scenarios is a PLC preferable to a custom electronic control system?

PLCs are often preferred in scenarios that require rapid implementation and standardized control, not too demanding and not particularly performing in terms of performance, design and user interface.

How does the integration of SCADA systems impact the use of PLCs versus custom electronic controls?

SCADA systems integration can significantly improve the monitoring and data analysis capabilities of PLCs and custom electronic controls. While PLCs work well with general-purpose SCADA, our custom controls allow for more precise integration, providing industry-specific insights and controls that standard PLCs typically can't match.

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