We have had a very positive response on our Allen-Bradley or AB
Rockwell Automation video lessons
with requests to produce more lessons on these PLCs
PLC is an acronym for Programmable Logic Controller
and PACs (PAC is an acronym for Programmable Automation Controller)
systems and associated programming.
As you may know, PLCs have come a long way over the last 50 years
with improved overall hardware and programming functionality,
and so that in short describes the differences between a PLC and a PAC.
PLCs have evolved into PACs.
With all of this in mind, this video lesson,
will provide a simple background and overview of the automation product lines.
The company was founded by Lynde Bradley in 1903
with the financial support backing of investor Dr. Stanton Allen,
the company eventually became the Allen-Bradley Company.
Allen-Bradley is the brand name of several product lines of factory automation equipment
and today its owned by Rockwell Automation.
Today, the company manufactures programmable logic controllers (or PLCs),
human machine interfaces, sensors, safety components and systems,
software, drives and drive systems, contactors, and motor control centers.
They are headquartered in Milwaukee, Wisconsin,
and landmarks the AB Clock Tower having features
with the largest four sided clock in the western hemisphere.
Their first patented product was a carbon disc compression type motor controller
used for industrial cranes
and the crane controller was exhibited at the St. Louis World's Fair in 1904.
Allen-Bradley became involved with programmable logic controllers
by the inventor, Odo Josef Struger.
He is often referred to as the "father of the programmable logic controller".
Odo contributed the ideas leading up to the invention of Allen‑Bradley PLCs
over a period from 1958 to 1960
and is accredited with inventing the acronym “PLC”.
Allen-Bradley became a major PLC manufacturer in the United States
during his employment with AB.
He also contributed as a leader in the development of “IEC 61131-3”
PLC programming language standards.
There you have it, a bit of history for a great company.
Now let us talk about the product line that makes them so great.
The first Allen-Bradley PLC introduced to the market
was the PLC-5 product family.
The PLC-2 and PLC-3 were released in the 1980s and are now obsolete.
These PLCs were followed by the PLC-5 and is still in use today.
The PLC-5 family used the 6200 series programing software originally
and then later “RSLogix 5” programming software.
In 1991 the SLC500 product line was released.
This platform was much smaller in size and had a reduced instruction set.
SLC was an acronym for Small Logic Controller
and the first SLC500 released was an integrated package
or commonly referred to as a shoe block PLC
containing the CPU, power supply, and IO.
Later the SLC5/01 was the first racked based SLC series released.
The 5/02 and 5/03 PLCs had DH485 or Data Highway serial-based communication
and the SLC5/04 provided a faster communication called DH+ or Data Highway Plus.
The SLC5/05 has both DH485 and Ethernet communications.
The Micrologix family and SLC 500 PLCs
used the RSLogix 500 programming software.
In 2014, the MicroLogix family was introduced in response
to address the need for a less expensive PLC solution to compete with other manufactures
and the first MicroLogix introduced was MicroLogix 1000
supporting several types of IO combinations.
The platform did not use a rack
but instead, modules were connected at the end of the package.
The ControlLogix family was introduced in 1997.
This platform was racked-based
having much faster scan times (or speed)
and memory than the PLC-5 or SLC products.
Communication modules supported Ethernet,
DeviceNet, DH485, and ControlNet.
Servo motor control cards using SERCOS fiber optics
provided competitiveness in the coordinated system servo market
The CompactLogix family was released in 2008
as a lower cost solution to ControlLogix for competitive reasons.
And like the MicroLogix, the products do not use a rack-based solution
but instead, use add-on modules to the ends of the power supply or CPU modules.
Communications between the RSLogix programming and configuration software
and PLC/PAC is handled using Rslinx software,
a separate software package, that also supports DDE and OPC support.
You can learn more about Rockwell Automation
by attending the Rockwell Automation "Automation Fair" held annually.
You can find the link to this website in the description.
This concludes, “An Introduction to Allen-Bradley PLCs
and the evolution of the Rockwell Automation PACs”.
I hope you have enjoyed learning about Allen-Bradley and Rockwell Automation.
Stay tuned for additional lessons about Rockwell Automation
and Software related programming technique topics.
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