PLC Brands Compared: Allen-Bradley, Siemens, Mitsubishi, and Schneider

Given the diverse and constantly advancing landscape of PLC brands, a strategic comparison of each brand’s unique features and capabilities is essential to choosing the best PLC for your application. Evaluating factors such as performance, design, safety, connectivity, scalability, and cost against your specific application needs will lead to the right decision. This article provides a detailed comparison of leading PLC brands:Allen-Bradley, Siemens, Mitsubishi, and Schneider PLCs.

The PLC Giant Allen-Bradley

Developed through a long history of technological advancements, Allen-Bradley PLC brands, by Rockwell Automation, are smart, high-performance, multi-disciplined control solutions. They leverage robust design and advanced technology to enable more operational efficiency, reliability, scalability, and application flexibility.

Prominent Allen-Bradley PLC Brands

• ControlLogix Series: A high-performance Allen-Bradley PLC brand that offers a powerful combination of integrated safety, high-speed processing, and built-in security. ControlLogix PLCs are designed to reduce engineering overhead, simplify complex industrial automation challenges, and enable smarter, more robust operations. Typical applications include process and batch control, discrete and motion control (e.g., packaging and robotics), as well as hybrid and safety-critical automation systems.
• CompactLogix Series: This Allen-Bradley PLC brand is designed to provide a scalable Logix solution for large and mid-size automation applications that require high data throughput and faster system performance. They also offer an integrated motion solution, machine-level control, increased capacity, enhanced security, and improved productivity.
• MicroLogix Series: Cost-effective Micro-PLCs that feature pulse train outputs, high-speed counters, enhanced network capabilities, greater I/O capabilities, and flexible communications. They are designed to handle an extensive range of control applications requiring a small I/O count.

Key Features

Here are some of the key features that make Allen-Bradley PLCs stand out among other PLC brands.

• Scalability and Modular Design: Allen-Bradley PLC brands allow for seamless expansion with no full system overhauls. For example, in a food processing plant, engineers can add I/O modules to running CompactLogix controllers to meet the I/O needs of new conveyor lines while reducing system downtime.
• Built-in Motion Control: This feature integrates motion control capabilities within the PLC module, thus eliminating the need for separate drives. For instance, an automotive manufacturer using a ControlLogix PLC brand can synchronize robotic arms with assembly robots, thereby achieving tight timing and increasing production rates upwards of 20%.
• Advanced Safety Integration: Allen-Bradley PLC brands include the GuardLogix PLC series, which offers embedded advanced safety functions in compliance with SIL 3 standards. Such PLCs are used in mining equipment to instantly stop operations upon detecting hazards, helping prevent accidents.
• Robust Networking Capabilities: They support a variety of industrial networks, including ControlNet, EtherNet/IP, PROFINET, and DeviceNet, allowing for high-speed data exchange. Using Allen-Bradley PLC brands in a pharmaceutical facility enables high-speed communication, enabling real-time monitoring of batch processes across several stations, thereby improving compliance with FDA regulations.

Siemens PLC Offerings

Siemens PLC brands are part of the SIMATIC controller portfolio, which includes PLC models like SIMATIC S7-1200 G2, SIMATIC S7-1500, SIMATIC S7-400, and SIMATIC ET 200SP.These PLC brands have been engineered for complex, data-intensive applications, such as renewable energy systems. They offer much more than robust hardware for controlling a wide variety of smart machines and plants. Through continuous innovations, Siemens SIMATIC PLCs enable state-of-the-art machine concepts – tailor-made for automation systems of all kinds. Whether you require powerful controllers for demanding industrial applications, a compact PLC platform with integrated functions, or PLCs for PC-based automation systems or distributed architectures, the SIMATIC PLC brand has the right controller for your needs.

Leading Siemens PLC Brands

• SIMATIC S7-1200 Series: This Siemens PLC brand includes compact PLCs designed to deliver smart, reliable, and efficient automation solutions. They offer enhanced performance, expanded memory, and integrated communication capabilities, enabling faster data processing and more controller multitasking. They essentially combine powerful processing capabilities with a space-saving design. The SIMATIC S7-1200-G2 PLCs are available in fail-safe and standard versions. The fail-safe controller models offer cost-effective, scalable, and optimized fail-safe technology to ensure safe machine operations.
• SIMATIC S7-1500 Series: It features advanced PLCs that are ideal for automating applications and entire production plants with extremely high demands for availability, flexibility, performance, and connectivity.
• SIMATIC ET 200SP: A robust, compact Siemens controller with a distributed architecture and high system availability. It is particularly well-suited for special-purpose applications and the manufacturing of series machines.

Key Features

Five defining features of Siemens PLC brands:

• High-Speed Data Processing: Siemens PLC brands boast cycle times under 1ms, which is essential for time-critical applications. High-speed printing presses, for example, employ SIMATIC S7-1500 controllers to achieve micron-level color registration, minimizing waste.
• Modular and Flexible Architecture: The Siemens TIA Portal supports customization across all of its PLC brands’ hardware. This feature would enable a wind turbine farm operator to scale Siemens PLC modules in response to fluctuating wind conditions to dynamically optimize energy output.
• Integrated Cybersecurity: Siemens PLC brands provide embedded cybersecurity features using OPC UA against such cyber threats. For instance, in smart grid applications, Siemens PLCs can prevent unauthorized access to the grid system, allowing uninterrupted power distribution.
• Advanced Diagnostics Tools: Siemens PLC Brands offer advanced tracing functionalities that can provide real-time fault information. For example, in chemical plants, a Siemens PLC can diagnose valve actuators to predict failures and extend equipment lifetime by 15-20%.

Mitsubishi Electrics Top PLC Brands

Mitsubishi’s main PLC brand is the MELSEC Series. This PLC series boasts compact footprints and energy-efficient controller solutions for small-sized to large and complex automation systems. MELSEC PLCs provide enhanced performance capabilities in compact packages ideal for space-constrained setups like electronics assembly

Flagship Mitsubishi Electric PLC Brands

• MELSEC iQ-R Series: A product line of innovative Programmable Automation Controllers (PACs) that incorporate a high-speed system bus. This revolutionary system bus offers improved productivity through powerful functionality and advanced performance.
• MELSEC iQ-F Series: High-performance compact-class programmable controllers with a variety of integrated functions. They are designed to provide superior drive control, outstanding performance, user-centric programming, and compatibility with IoT.
• MELSEC-Q Series: This Mitsubishi PLC brand incorporates multiple CPU architectures, offering an extensive range of highly functional and high-speed CPUs. This enables simultaneous control of multiple operations, enhancing the overall system’s performance, efficiency, scalability, and flexibility.
• MELSEC-F Series: It incorporates a CPU, power supply, and I/O modules into a single compact package. It offers a diverse range of features with a flexible system configuration, allowing users to expand its capabilities as needed.

Key Features

Key features that distinguish Mitsubishi PLCs from other PLC brands

• Ultra-Compact Design: Mitsubishi PLC brands that incorporate the FX5 series CPUs are highly compact, i.e., they can fit in tight enclosures without compromising the power needs. They are widely used in consumer electronics and in multi-axis pick-and-place machines, saving on valuable floor space.
• High Reliability in Harsh Environments: Rated for extreme temperatures and vibrations, MELSEC PLCs can withstand demanding operating conditions. Oil rig platforms mainly use Mitsubishi PLCs to control drilling pumps operating at a -40 to 70°C temperature range.
• Energy-Efficient Operations: Using MELSEC PLCs with in-built power management features helps reduce power consumption by up to 50% compared to older PLC brands. This helps reduce operational costs without compromising throughput.
• Advanced Positioning Control: Mitsubishi PLC brands incorporating the SSCNET III/H network provide very precise servo control. This is necessary in textile mills as it helps achieve uniform fabric tension in warp knitting machines.

Schneider Electric PLC Family

Schneider Electric’s Modicon product line offers a diverse range of PLC brands for automating small to advanced machines across manufacturing industries. They are designed to provide digitized control over highly precise mechanical or robotic operations. IIoT-connected Modicon PLs are easy to configure, commission, troubleshoot, and maintain.

Most Popular Schneider PLC Brands

• Modicon M221: A nano-PLC series engineered to control machines for basic automation. It uses Machine Expert programming software and TM3 I/O expansion modules.
• Modicon M241: A micro-PLC series designed for high-performance modular machines. It is programmed using Machine Expert and is compatible with TM3 input/output expansion modules. With outstanding performance and versatile connectivity, Modicon M241 PLCs are used in complex machines that incorporate position and speed control functions.
•  Modicon M251: A compact, micro-PLC series built to handle more complex machine automation with dual-channel communications. Modicon M251 PLCs with dual-channel support for Modbus TCP, CANopen, and EtherNet/IP-based communications can handle both upstream and downstream communications. This allows users to connect to MES, ERP, and SCADA systems via standard Ethernet cables or Wi-Fi.

Key Features

Five outstanding features of Schneider PLC brands

• Open System Architecture: With support for multiple communication protocols, Schneider PLC brands facilitate seamless integration of legacy and modern control systems. For instance, Modicon M580 PLCs used in commercial building HVACs enable connections to BACnet networks, enabling efficient energy use.
• Improved Cyber Security: Achilles Level 2 certification of Modicon PLC brands ensures that these controllers are protected against even sophisticated cyber-attacks. Such PLCs are used in water utilities to control remote pumping stations while ensuring service integrity.
• Scalable Performance: Modicon PLCs can handle up to 128 I/O points, provide distributed control, and manage robotic sorters that process thousands of orders every hour in e-commerce fulfillment centers.
• User-Centric Design Tools: Schneider PLC brands incorporate Drag-and-drop libraries that help speed up their commissioning. When such PLCs are used in pharmaceutical mixers, they ensure precise adherence to the recipe for batch-to-batch consistency.

Choosing Among Different PLC Brands: What to Consider

Some of the key guiding factors when selecting a PLC brand for your application include:

• Scale and Complexity: Allen-Bradley and Siemens PLC brands provide advanced features and ecosystem support for large and complex automation systems. For smaller machines, PLC Brands such as Mitsubishi or Schneider provide a better option.
• Connectivity and Future-proofing: Consider the support for modern industrial networks like Ethernet, OPC UA, ControlNet, PROFINET, and EtherNet/IP. Scalable PLC brands are suitable for future expansion needs.
• Cost versus Performance: Different PLC brands have varying up-front costs and different life-cycle costs. Choose a brand whose features match your project requirements without over-specifying.
• Industry and Domain Fit: Some PLC Brands have a stronger presence in particular industries, such as Siemens PLCs, which are widely used for process control, Allen-Bradley PLCs, for discrete manufacturing, or Schneider PLCs, for infrastructure management.

Final Thoughts

When it comes to automation, there are hundreds of options to choose from, each with its own strengths and weaknesses. Whether it’s Allen-Bradley’s offering and their advanced motion control or Modicon with their industry 4.0-focused M580 line. Rest assured, we carry many of these options and more here at DO Supply. We specialize in all things automation, including PLCs, drives, accessories, motors, and more! We also offer our own in-house warranty repairs, backed by our two-year warranty, to keep your installation stress-free. Come visit our site to see what we can do for you!