The history of AB PLC, a key company under Rockwell

A-B PLC Introduction:
Allen-Bradley, referred to as A-B, was founded in 1903 and is a well-known brand of Rockwell Automation.

Rockwell is an industrial automation multinational company that provides first-class power, control and information technology solutions for the manufacturing industry. Rockwell Automation integrates well-known brands in the field of industrial automation and is committed to creating a full range of automation solutions to help customers improve productivity. These brands include Allen-Bradley’s control products and engineering services, Reliance Electric’s motors and drive products, Dodge’s mechanical power transmission products, and Rockwell Software’s industrial control software. Allen-Bradley launched its first programmable controller, the 1774 PLC, in 1970, and created the name “PLC” with its parent company Rockwell Automation. It is a major player in the field of control systems. Now almost all control engineers are familiar with the name Rockwell Automation or Allen-Bradley.

The 1774 PLC pictured above is one of the first PLCs ever built

The PLC-1 was followed by the PLC-2 and PLC-3, then the PLC-5 family of products, which still includes many devices in operation today! The SLC500 series, released in 1990, was followed in later years by the CompactLogix and MicroLogix series, which have also been developed to this day.

In 1985, large manufacturing company Rockwell International acquired Allen-Bradley, which became Rockwell’s Industrial Automation Division. Today, the Rockwell and Allen-Bradley brand logos are almost interchangeable in the inner workings of control cabinet software and hardware.

Another important milestone was the release of the SLC500 PLC platform in 1990, which was more compact and affordable than its predecessor, the PLC-5.

SLC500 Series:
SLC500 is a mid-range model with simple programming, high stability, rich functions, hardware that can adapt to harsh environments, rich instructions, good compatibility, and strong communication capabilities. It is equivalent to Siemens S7-300 and uses RSLogix 500 (equivalent to Siemens SIMATIC-STEP7) programming software. The latest version is RSLogix 500 V16.

At the same time as the release of the SLC5/02 and 5/03 models, Allen-Bradley introduced the DH485 data highway. It is based on the RS-485 standard and is designed for factory floor applications. The SLC5/03 was the first product to introduce common PLC functions such as online programming and run mode. It was also the first product to support firmware upgrades. The successive model SLC5/04 introduced an enhanced version of the data highway, called DH+.

The picture above is an SLC system with a 5/03 controller

The last model in the SCL 500 series is the SLC 5/05, which is the first Allen-Bradley PLC capable of Ethernet-based communications. The DH+ or DH port of previous models has been replaced with an Ethernet port, which now transmits at speeds of up to 100 Mbps. The SLC 5/05 is available in three memory sizes: 16k, 32k, and 64k. This PLC is the only one in the SLC series that is still supported by Allen-Bradley today.

In the latest major hardware revision based on the chassis platform, Allen-Bradley released the new ControlLogix automation controller series. In later years, the MicroLogix series and CompactLogix series were launched in an attempt to cover other market areas with specific project scopes. Let’s review Allen-Bradley’s three Logix PLC series:

1.  ControlLogix series

• The ControlLogix PLC is the first released part of the Logix platform. These general-purpose controllers are modular and rack-mounted. They consist of power supplies, processors, I/O and communication modules.
• ControlLogix is ​​a high-end PLC for complex and large control systems. It is a high-end mainstream model with large capacity, high performance, high reliability, powerful communication functions, modular design, rich programming tools, high security, good real-time performance, and easy configuration and programming. For example, ControlLogix 5570, ControlLogix 5580, etc. are equivalent to Siemens’ S7-400 and 1500 series. In the early days, RSLoaix 5000 (equivalent to Siemens’ SIMATIC-STEP7) programming software was used. The latest version is RSLoaix 5000 V21. Now it is also applicable to Studio5000 (equivalent to Siemens’ TIA Portal). The latest version is Studio5000 V36.
• The first controller in this series was 1-L1999, which was launched in 1756. Since then, many generations have been released. This platform replaces the PLC-5 and SLC series, offering faster scan times, more significant advantages and higher storage capacity.

The picture above is a ControlLogix control system

• The latest model in the series is the ControlLogix 5580 or L8x, which is 7 times faster than its predecessor, the L20 series. The ControlLogix5580 is equipped with 3MB to 20MB of memory. They are compatible with all Allen-Bradley communication protocols: ControINet, EthernetiP, DeviceNet, and DH+. Ethernet/P speeds can reach up to 1Gbps, which is generally sufficient to meet the needs of modern automation with large amounts of data.

2. MicroLogix Series

• In 1994, Allen-Bradley introduced the MicroLogix pioneering compact and cost-effective product line. These smaller controllers are equipped with built-in processors, I/O and power supplies, designed for small applications, and some models support both embedded and expanded I/O. Many models from 1000 to 1500 are now discontinued, but they are still widely used.
• MicroLogix is ​​a compact PLC suitable for small applications. It is a low-end model with low cost, small size, high reliability, simple use, rich functions, rich communication interfaces, scalability, and friendly programming software. It is suitable for small equipment and simple process control occasions, such as MicroLogix 1400 (equivalent to Siemens S7-200 series). Use RSLogix 500 (equivalent to Siemens SIMATIC-STEP7) programming software, and the latest version is RSLogix 500 V16.

The picture above shows the Micro830 series controller

• The latest revision of the Micro series is the Micro800 series, which was first introduced in 2014. It includes many of the same design considerations, such as embedded I/O terminals on the bottom and top, and integrated communication channels such as Ethernet and USB. The Micro800 series also includes front connections for additional modules, further improving functionality.

3. CompactLogix Series

• The CompactLogix PLC was first released in 2008 to meet the market’s demand for more cost-effective controllers.
• CompactLogix is ​​a mid-range model with high reliability, high performance, modular design, miniaturization, rich communication interfaces, rapid deployment, high cost-effectiveness, powerful diagnostic functions, and scalability. For example, CompactLogix 5380, CompactLogix 5480, etc. In order to replace the SLC500 series (equivalent to Siemens S7-300 and 1200 series), RSLoaix 5000 (equivalent to Siemens SIMATIC-STEP7) programming software was used in the early days. The latest version is RSLogix 5000 V2. Now it is also applicable to Studio5000 (equivalent to Siemens TIA Portal). The latest version is Studio5000 V36.
• The CompactLogix series has two variants, one of which includes modular but chassis-free controllers, including L30ER to L35X models. The other variant includes multi-machine controller solutions, such as L23, L1XER and L2XER models with embedded digital and analog I/O connections.

The above picture is a CompactLogix control system

All current CompactLogix PLCs are equipped with a slot for an SD card and an embedded USB port.

Summary: For more than a century, Allen-Bradley has been a major force in the industrial engineering community, with products ranging from power control and indication units, programmable program controller operation interfaces, motion control products, and integrated architecture motion control systems. These products are widely used in various industrial fields to help customers achieve higher production efficiency, precision and safety. The control system software and hardware it produces with Rockwell Automation will definitely become a major player in almost every industry, suitable for almost any project size and scope.