Like many other vendors, Rockwell Automation has recently rebranded and reorganized their offering. The ControlLogix family is a part of Rockwell Automation's larger solution offering called Integrated Architecture. It is a relatively new term in the world of Rockwell Automation, but the concept has been in place for quite some time. It represents a convergence of the control and information systems within an industrial operations environment. This convergence is in line with the industry trend we have witnessed over the past decade and has increased the ties between Operational Technology (OT) and traditional Information Technology (IT). We have seen a continuous increase in demand for operational information to be provided to the corporate information system in real time in order to fulfill the maintenance needs, environmental reporting, accounting, and other corporate requirements. At the same time, we have seen OT move from proprietary protocols and data access technology to traditional IT technologies such as TCP/IP and Ethernet. The promise of Integrated Architecture is the ability to easily implement plant-wide optimization, reduce technical project risk, increase machine performance, and improve long-term reliability.

The five core technologies of Integrated Architecture Programmable Automation Controller (PAC) product line include the following platforms:

The preceding diagram outlines the Integrated Architecture structure and shows where ControlLogix fits into the mix. The FlexLogix (bulletin 1794) controllers were also part of the Logix PAC family and was used to communicate with PLC-5 and SLC 500 Flex I/O blocks. However, FlexLogix has now been retired from the lineup, so it will not be covered in this book.

The product, formally known as RSLogix 5000 (used for programming the ControlLogix and CompactLogix controllers), is now included within the automation engineering and design software suite called Studio 5000 and is now referred to as Logix Designer. For the remainder of this book, we will be using the terms—Logix Designer, RSLogix, and Logix—interchangeably to refer to the Logix controller family programming environment.

ControlLogix controller was first launched in 1997 as a replacement for Allen-Bradley's previous large-scale control platform, PLC-5. The ControlLogix platform includes a bulletin 1756 ControlLogix 5550 controller, bulletin 1756 ControlLogix I/O modules, and the RSLogix 5000 programming software platform (now referred to as Studio 5000 Logix Designer). ControlLogix represented a significant technological step forward that included a 32-bit ARM-6 RISC-core microprocessor and an ABrisc Boolean processor combined with a bus interface on the same silicon chip. At launch, the series 5 ControlLogix (also referred to as L5 and ControlLogix 5550) controllers were able to execute the code three times faster than PLC-5. The following diagram is an illustration of the original Logix L5 controller:

The L5 controller is considered to be a PAC rather than a traditional PLC due to its modern design, power, and capabilities beyond a traditional PLC (such as motion control, advanced networking, batching, and sequential control). The ControlLogix platform is built on the ControlBus backplane, which performs like a mini-network and allows devices to be Removed or Inserted Under Power (RIUP).

L5 has since been retired from the lineup, so we will focus on the newer L6 and L7 controllers in this book. Throughout this book, we will be referring to the ControlLogix controllers as PACs, which are the modern day equivalent of PLCs.

The entire Logix family of controllers (ControlLogix and CompactLogix) has diverged from traditional synchronous PLC scan architecture in favor of a more efficient asynchronous operation. Like most modern computer systems, asynchronous operation allows the Logix controller to handle multiple tasks at the same time by slicing the processing time between each tasks. The continuous updating of information in an asynchronous processor creates some programming challenges, which we will address throughout the book. The following diagram illustrates the difference between the synchronous and asynchronous operation:

In 2002, the bulletin 1756 ControlLogix L6 (Logix556x) processor was released with a more powerful processor and more memory, and the CompactFlash nonvolatile memory card was added to the entire lineup.

ControlLogix represents a common control engine with a common development environment and tight integration between the programming software, controller, and I/O modules. This close integration greatly reduces automation engineering development time and cost.

In 2010, Rockwell Automation launched the series 7 (also referred to as L7 and ControlLogix 5570) controllers, which featured the following enhancements over the series 6 (L6) controllers:

When selecting a ControlLogix controller, it is important to consider the following points:

The ControlLogix series 6 and series 7 controllers and their software version compatibilities are shown in the following table:

It is important to note that the L6 controllers are not supported in Version 21 and higher of Studio 5000 Logix Designer.

With the launch of the (bulletin 1756) GuardLogix controller in 2005, the ControlLogix platform supported both standard and safety system control in the same chassis. The GuardLogix controller system is designed for use in safety applications, including SIL 3 (IEC 61508) and the ISO standard for Safety of Machinery (ISO 13849-1 General Principles for Design and PLe/Cat.4). GuardLogix safety controllers represent an essential piece of a fail-safe (de-energize to trip) solution. Fail-safe refers to a solution that when a fault is detected, all of its outputs are set to zero. And, in the event of a faulty input or input module, it automatically sets any input values associated with them to zero. Both the L6 and L7 controllers are available in the GuardLogix form factor. Physically, the GuardLogix controllers feature a red faceplate and are usually installed in pairs—primary and safety partner controller. The GuardLogix controllers are only supported in Version 18 and higher of RSLogix 5000 and Studio 5000 Logix Designer.

The Rockwell Automation's extreme environment controllers (bulletin 1756 ControlLogix-XT) share the same features and programming interfaces as the standard ControlLogix controllers, but are certified to operate in extreme conditions. The ControlLogix-XT modules are darker gray in color than the ControlLogix modules and are spaced in every other slot to provide an improved ventilation/isolation. In addition, the ControlLogix-XT modules are treated with a conformal coating that improves the product's resistance to corrosive environments. The ControlLogix-XT controllers and modules are rated for temperatures ranging from -20°C to 70°C (-4°F to 158°F) and have the following environmental certifications—cULus, Class 1, Div 2, C-Tick, CE, ATEX Zone 2, SIL 2, IEC 61131-2, ANSI-ISA-S71.04-1985, Class G1, G2, and G3. The L6 and L7 standard controllers and GuardLogix controllers are all available in Extreme Environment (XT) form factors.

In 2006, Rockwell Automation first shipped the (bulletin 1768) L43 CompactLogix controllers targeted at cost effective, small- to medium-size automation solutions. At the time of launch, CompactLogix controller was planned as the long-term replacement for the SLC 500 controller family. The CompactLogix control platform is designed with an emphasis on the controller software. As the CompactLogix hardware evolves with an improved performance and additional features, the logic will easily migrate to new hardware and firmware versions. Unlike the SLC 500 platform, the CompactLogix controllers can be programmed using the same RSLogix 5000 (Logix Designer) software suite that is used with ControlLogix. In 2006, CompactLogix L43 with integrated motion support was added to the family. It features a CompactFlash memory card, Ethernet port, Serial RS-232 port, 1769 / 1768 modules, and a power supply module. The following is an illustration of the L43 CompactLogix controller:

CompactLogix controller-bulletin 1768—L43 and L45

In 2008, Rockwell Automation released the low-cost CompactLogix L23 controllers (bulletin 1769) with embedded I/O. The L23 controller features a serial RS-232 port, Ethernet port (only on the E models), embedded I/O, and an embedded power supply. The following is an illustration of an L23 controller:

CompactLogix controller-bulletin 1769 L23x Packaged controllers with embedded I/O

Also in 2008, Rockwell Automation released the (bulletin 1769) CompactLogix L3x modular controllers. The 1769 CompactLogix modules do not have a chassis like the ControlLogix modules. The 1769 CompactLogix modules can be connected together using a DIN rail or can be screwed in directly to a panel. CompactLogix L3x features a CompactFlash memory card, serial RS-232, ControlNet or Ethernet port, and a power supply module. The following diagram is an illustration of the CompactLogix L3x controller:

CompactLogix Controller-Bulletin 1769-L3x Modular controllers

In 2009, Compact GuardLogix, an SIL3 certified controller, with the L43S and L45S CPU supporting integrated safety, was added to the Logix family.

In 2012, Rockwell Automation released the (bulletin 1769) CompactLogix 5370 L1, L2, and L3 controllers, which provided a low-cost Ethernet/IP-enabled, high-performance controller in a 40 percent smaller form factor than ControlLogix. The CompactLogix 5370 series controller provides many of the same enhancements that the ControlLogix series 7 provided over the ControlLogix series 6 controllers, including the following properties:

The following table provides illustrations of the CompactLogix 5370 controllers and their distinguishing features:

CompactLogix Controller—bulletin 1769 5370—L1	Features
CompactLogix 5370 L1 Controller	SD memory card
	2 X Ethernet ports
	USB 2.0 port
	Embedded point I/O modules
	Expandable with 6 or 8 point I/O modules
	Embedded power supply
	Integrated motion control
CompactLogix Controller—bulletin 1769 5370—L2	Features
CompactLogix 5370 L2 Controller	SD memory card
	2 X Ethernet ports
	USB 2.0 port
	Embedded 1769 I/O modules
	Expandable with 4 x 1769 I/O modules
	Embedded power supply
	Integrated motion control
CompactLogix Controller—bulletin 1769 5370—L3	Features
CompactLogix 5370 L3 Controller	SD memory card
	2 X Ethernet ports
	USB 2.0 port
	8 to 30 1769 I/O modules
	Power supply module

There are many factors to consider when selecting a CompactLogix controller due to their module nature and wide range of form factors which are available:

The CompactLogix controllers and their software version compatibilities are shown in the following table:

It is also important to consider that some of the CompactLogix 5730 controllers are slated as direct replacements for some of the older CompactLogix controllers (although the older controllers are still available for purchase):

Due to the long life span of most industrial PACs, it is common to encounter controllers still running legacy firmware. Controller firmware versions and RSLogix 5000 and Logix Designer versions go hand in hand. If you are working on the ControlLogix or CompactLogix controller that is running firmware version 13.03, you should be using RSLogix 5000 Version 13.03 to program it. As updating firmware can introduce process downtime, it is important to understand and work with the capabilities of older firmware and software versions:

Rockwell Automation provides a software suite called Product Selection Toolbox, which is designed to help you select and design Integrated Architecture solutions. This software suite provides helpful tools for evaluating the size of your application, generating drawings, and even estimating the cost of your application. This product is available for free to approved partners and customers.

In this chapter, we learned about the controllers available within Rockwell Automation's Integrated Architecture. We also explored the history of Rockwell Automation and evolution of the industry-leading Logix platform. We now have an idea of the controller solutions available within Integrated Architecture, and are capable of making basic solution architecture decisions. In the appendix of this book, you can find links to Rockwell Automation Literature Library where you can dive deeper into the topics covered in this chapter.

In the next chapter, we will introduce the various networking and communication options available for the Rockwell Automation Logix controllers.