This book begins with some background history of industrial control systems and the Rockwell Automation ecosystem. It is essential to understand the legacy systems provided by Rockwell Automation because some of them can still be found operating in the field today. Also, it is important to understand the overall Rockwell Automation offering, the terminology, and how the platforms we focus on in this book fit into that world.
In this chapter, we will introduce Rockwell Automation and provide a history of the evolution of their technologies, right up to the Logix platform. Due to the 15- to 20-year industrial controller lifespan, it is not uncommon to encounter older versions of hardware and firmware and so it is critical to understand their evolution.
The following topics will be covered in this chapter:
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Controlling equipment with water...
Controlling equipment with water, air, and power
The earliest control systems can be traced back to the float regulator mechanisms that were used in Greece around 270 BC. The need for accurate time tracking inspired the Greek water clock (clepsydra), which leveraged the simple float regulator to maintain a constant flow of water. The float regulator would maintain the water level in a primary tank at a constant depth; water kept at a constant depth maintained a constant water pressure.
Constant pressure resulted in a constant flow of water through a tube that would fill a secondary tank at a constant rate. The level of the second tank was used to measure time, which was displayed on a dial using a second float. A similar float regulator mechanism is still used in our toilets today. A construct that uses input from another device (float) to maintain a value (water level) is called a feedback controller.
The following diagram details the components of a simple Greek...
A brief history of Rockwell Automation
In 1901, while working for Milwaukee Electric, Lynde Bradley (a teenager at the time) devised a better way to build the controllers that regulate motor speed. He soon quit his job, secured a small $1,000 investment from his lifelong friend, Dr. Stanton Allen, and co-founded the Allen-Bradley company with his brother, Harry Bradley, in 1903. The primary focus of Allen-Bradley was,for several decades, motor controllers, until they received an unusual request from GM in 1968 to build a system to replace their hardwired relay logic with something more dynamic—a standard machine controller.
Program Data Quantizer II and the Programmable Matrix Controller
Allen-Bradley responded to GM's request with two solutions—first, a large, difficult-to-program, expensive minicomputer-based Program Data Quantizer (PDQ) II in 1970 and later, the smaller and easier-to-program Programmable Matrix Controller (PMC) in 1971. The...
Understanding Integrated Architecture
Like many other vendors, Rockwell Automation has recently rebranded and reorganized its offering. The ControlLogix family is part of Rockwell Automation's larger solution offering, called Integrated Architecture. Integrated Architecture 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 operating environment. We have seen a continuous increase in demand for operational information to be provided to the corporate information system in real time to fulfill maintenance needs, environmental reporting, accounting, and other corporate requirements. At the same time, we have seen operational technology 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 implement plant-wide optimization...
Summary
In this chapter, we delved into the history of industrial automation, starting with the Greek water clock and moving right up to modern control systems. We learned about the controllers and product lines that were developed by Allen-Bradley and Rockwell Automation over the years and discussed their evolution. We also touched on the modern controller solutions that are part of Studio 5000 and Integrated Architecture.
In the next chapter, we will take a deep dive into the ControlLogix platform and start to work with modern Rockwell Automation controllers.
Further reading
For more information on the history of Allen-Bradley and Rockwell Automation, take a look at the Our History section of the Rockwell website at https://www.rockwellautomation.com/en_NA/about-us/overview.page?pagetitle=Our-History.
Questions
The following questions can be used to test your retention of the concepts introduced in this chapter. You can find the answers to these questions in the back of the book under Assessments:
- What device is considered to be one of the first control systems?
- What device did Samuel F. B. Morse create in 1836 that is still widely used in automation systems today?
- What was the name of the company started by Lynde Bradley and Harry Bradley in 1903?
- What was the name of the device created as a result of the GM request for information to replace hardwired relay logic in 1968?
- What PLC platform was launched in 1991 that was designed to be used in smaller plants and stands for Small Logic Controller?
- What PLC platform was launched in 1997 as a replacement for Allen-Bradley's previous large-scale control platform, the PLC-5?
- What is the Rockwell Automation umbrella term for integrated convergence...