Programmable Control (PLC & PAC) White Papers & Technical Articles

Articles and white papers on Programmable Control (PLC & PAC) technologies used in the automation, process control, and instrumentation industry.

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Databases – The Perfect Complement to PLCs, December 2009
By Steve Hechtman, Inductive Automation
SQL and relational databases form the bridge to integrate processes, machinery and people together. Working with SQL is remarkably similar to working with PLCs and ladder logic. And that’s why the PLC programmer is best suited to implement solutions involving PLCs and relational databases. Click here to read full article...

Coder’s Corner: PLCopen Standards Architecture & Data Typing

By Dr. Ken Ryan, Alexandria Technical College
This is the first in a series of articles focused on writing code using the IEC 61131-3 programming standard. This article outlines the major components of the software model. Later tutorials will focus on specifics of the POUs with emphasis on the differences between programs, function blocks and functions. Click here to read full article...

Safety PLCs Provide Space Savings For OEMs, June 2009
By Dave Collins, Schneider Electric
Safety PLCs provide all of the same functionality of traditional safety relays, but offer space savings and improved communications, while also providing the safety levels needed for the protection of personnel. Click here to read full article...

What's in a name?

by Jeff Payne, AutomationDirect
PLC, DCS and PAC are a few acronyms used to describe what originally replaced relays in the late 1960s. So, what are the differences and why do we need to call them by so many different names? Click here to read full article...

How to connect a Siemens PLC to USB

A SSW5/USB converter cable from Systeme Helmholz can be used to connect a Simatic S5 CPU to a PC with a USB interface. Here’s how. Click here to read full article...

Diagnosing NASA’s Deep Space Network Antennas

JPL uses load cells and Opto 22’s SNAP PAC system to discover cause of failed bearings in deep space antennas. Click here to read full article...

Understanding Programmable Automation Controllers (PACs) in Industrial Automation

Automation manufacturers have responded to the modern industrial application’s increased scope of requirements with industrial control devices that blend the advantages of PLC-style deterministic machine or process control with the flexible configuration and enterprise integration strengths of PC-based systems. Such a device has been termed a programmable automation controller, or PAC. Read full white paper by Opto22.

Connecting to the PLC from a Remote Location

Industrial automation is no longer limited by the walls of a production facility. More and more automation is being handled via remote communication, whether it’s from the office or from the comfort of your own home. Today’s PLCs give you the ability to access your control system to handle such tasks as monitoring via a website to determine the condition of a machine or check other statistics. With the latest PLC technology, almost anything that can be accomplished next to the machine can be accomplished wherever there is an Internet connection. Read full article by Paul Reszka of WAGO Corporation.

What is a Programmable Automation Controller (PAC)?

The ARC Advisory Group is generally recognized as the originator of the term "Programmable Automation Controller" (PAC). It was first coined in 2001 as a way to help automation hardware users better define their application needs and to give automation hardware vendors a term to more clearly communicate the capabilities of their products. Recently many vendors have begun classifying their newest or high-end systems as PACs, while others have come to use the term interchangeably with the term PLC. Despite these inconsistencies, PACs have a definite feature set, and their similarities to PLCs are as numerous as their differences. Watch flash presentation offered by Opto22.

PACs for Industrial Control, the Future of Control

With a number of vendors producing Programmable Automation Controllers that combine the functionality of a PC and reliability of a PLC, PACs today are increasingly being incorporated into control systems. This white paper explores the origins of the PAC, how PACs differ from PLCs and PCs, and the future direction of industrial control with PACs. Read complete article

The PLC: New Technology, Greater Data Sharing

Programmable Logic Controllers (PLC) continue to evolve as new technologies are added to their capabilities. The PLC started out as a replacement for banks of relays. Gradually, various math and logic manipulation functions were added. Today they are the brains of the vast majority of automation, processes and special machines. PLCs now incorporate smaller cases, faster CPUs, networking and various internet technologies. Read full article...

Web-enabling Your PLC

Enough has been written during the past couple years to convince most plant managers of the benefits of connecting plant floor equipment and processes to the Internet or Intranet. So, now that we're all convinced of the benefits of web-enabled automation, what pieces and parts are required to put this technology to work? Read full article...

Integrating PLCs into Process Weighing Systems

A typical weighing system consists of a weight controller, a load cell based platform scale, and a programmable logic controller. Read full article...

Removable Storage Media Add Flexibility to Modern Day PLC’s

The question “Why can’t my PLC interface easily to off-the-shelf devices?” is being answered by a new wave of PLCs with standard interfaces to common peripheral devices. Without sacrificing the deterministic operation, reliability, and ease of use of the traditional PLC, modern day PLCs are now incorporating more and more PC features than ever before. Read full article by Mark DeCramer of WAGO Corporation.