edge computers and programmable logic controllers high tech abstract

In the realm of computing and automation, a vital distinction to understand is the difference between a Programmable Logic Controller (PLC) and an edge computer. Recognizing that these two technologies serve unique purposes and roles is essential for anyone navigating this field. This article delves into the fundamental differences in design, purpose, and application areas of PLCs and Edge Computers.

1. Primary Function

PLC: Primarily used for industrial automation, PLCs control machinery and processes in environments like manufacturing plants and assembly lines. They are optimized for reliability, handling real-time control tasks, and operating in tough industrial conditions.

Edge Computer: These systems bring computation and data storage closer to the location where it’s needed, aiding in quicker response times and saving bandwidth. Edge computers find their use in various applications, including Internet of Things (IoT), AI processing at the edge, local data processing, and more.

2. Processing Capabilities

PLC: PLCs usually have limited processing power but are focused on real-time control tasks with deterministic performance, designed for more than simple data processing tasks.

Edge Computer: Boast greater processing capabilities, capable of handling complex algorithms, including AI and machine learning models, making them suitable for data-intensive applications.

3. Environmental Tolerance

PLC: These are built to endure harsh industrial environments, featuring robust casings providing resistance to elements like dust, moisture, vibration, and extreme temperatures.

Edge Computer: The design and tolerance vary widely. Some industrial-grade edge computers can be rugged, while some are designed for less demanding environments.

4. Connectivity and Communication

PLC: Often include a range of industrial communication protocols (Modbus, Profibus, Ethernet/IP) and are focused on interfacing with sensors, actuators, and other control systems.

Edge Computer: Offer a broader array of connectivity options (Wi-Fi, Bluetooth, cellular, Ethernet, etc.) and are designed to interface with a wide range of devices and systems, including cloud services when it makes sense.

5. Software and Programming

PLC: Programmed using specialized languages like Ladder Logic, Function Block Diagram, and Structured Text. PLC programming focuses on automation and control logic.

Edge Computer: Run on more general-purpose operating systems (like Linxus and Windows), they support a wide range of programming languages and frameworks.

6. Use Cases

PLC: Ideal for repetitive, high-speed automation tasks in manufacturing, process control, and other industrial applications.

Edge Computer: Used in smart cities, IoT devices, remote monitoring, autonomous vehicles, and where local data processing is essential.

7. Scalability and Flexibility

PLC: Scalability is typically limited to the number of I/Os and the processing capacity of the PLC. They are much less flexible in terms of upgrading and adapting to new technologies.

Edge Computer: Offers more scalability in terms of computing power and storage and can be easily updated or replaced to accommodate new technologies.

No One Technology Can Rule Them All

PLCs are specialized devices designed for industrial control and automation, offering high reliability and support for specific communication protocols. Edge computers, on the other hand, provide general-purpose computing capabilities suitable for a wide range of applications, including data processing, AI, and IoT.

The choice between a PLC and an edge computer largely depends on the specific requirements of the application, such as the need for real-time control, environmental conditions, processing power, and the type of data handling required. In fact, in many cases, a choice doesn’t need to be made: the future of industrial automation is PLCs and edge computers (and the cloud) working together to solve the most critical operational and analytical challenges.

For more on how edge and micro clouds can be used to solve challenges that PLCs cannot address alone, see the Pratexo Platform Page.

– Petter Graff, Pratexo Founder and CTO