MARCH 2015

STATE OF TECHNOLOGY REPORT

PLCs/PACsOne convenient eBook with the latest

technology trends, back-to-basics tutorials and

application stories on industrial controllers—

from PLCs to PACs

IDEAL FOR IoT

APPLICATIONS

PFC200 - Control Design - March2015 - eBook.indd 1 3/5/15 2:41 PM

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Table of ContentsFrom Its Inception, the PLC Has Changed Industrial Technology 6

Trends in TechnologyWhat OEMs Don’t Tell End Users About PACs 7PLC, PAC and IPC Standoff 9Industrial Controller Programming Top Needs 14Is PLC a Dirty Word Now? 15Combine Control and Operator Interface 17

Back to the BasicsWhat Exactly Is a PAC? 20A PLC by Any Other Name 25Five Must-Have Controller Programming Features 27Controller by Any Other Name 29

The Many Faces of PACs 33

Technology in ActionGo Small, Get Flexible: Bigger Isn’t Always Better for Machine Builders 35Before Ripping Out That Old Automation System, Try Getting It Back in Shape First 37Software at the Core of AB Controls 43OEM Builds Flexible Machines for Demanding Customers 45

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6

The PLC is dead!Long live the PLC!Since its inception in the 1960s, the programmable

controller has developed into much more than just an alternative to hardwired relays. Dick Morley, an MIT graduate who’s often regarded as the father of the PLC, probably had no idea where his work and the work of his colleagues would lead when the Modicon PLC, now part of Schneider Electric, was first introduced. And Odo Struger, an Austrian engineer who moved to Cleveland and is also known as the father of the PLC because of his work on the architecture of the first Al-len-Bradley controller, now part of Rockwell Automa-tion, would be equally impressed by the life that ma-chine smarts has made for itself.

The programmable logic controller (PLC) is essen-tially an industrial mini-computer, capable of being pro-grammed with one of the IEC 61131-3 languages. Its pri-mary benefit when first introduced was the elimination of problems associated with altering a manufacturing process; the massive web of relays, wiring and terminal

blocks created an array of potential issues each time a machine needed a changeover.

Ladder logic was and still is the programming language of choice, but many things have changed over the years. There’s no longer the need for pro-prietary terminals, and I/O options have exploded. Plus, memory and programming capabilities have improved over the decades, and the hits just keep on coming. PLCs are designed to exist in industrial environments, and they can handle a high number of I/O arrangements, which connect to a variety of sensing devices, as well as actuators that operate mo-tors or f luid-powered cylinders. And the human-ma-chine interface (HMI) has been a major evolutionary step in the PLC’s development.

Near the dawn of the millennium, ARC Advisory Group coined a new term—the “programmable au-tomation controller” (PAC)—although much discus-sion has taken place over the years as to what spe-cif ically dif ferentiates a PAC from a PLC. Trends, Back to Basics and Technology in ActionThis State of Technology Report explores in greater de-tail the trends that have shaped PLC/PAC machine con-trol, the fundamentals of the technology, and real-life examples of implementation that have proven success-ful. Drawn from the most recent articles published in Control Design, this special report includes arti-cles on emerging developments, basic primers and ma-chine-control examples illustrating the latest technol-ogy in action. We hope that you find it useful.

- The Editors

From Its Inception, the PLC Has Changed Industrial TechnologyOriginally an alternative to hardwired relay configurations, the programmable logic controller

has expanded its capabilities over the years, no matter what you call it

“ PLCs are designed to exist in industrial envi-

ronments, and they can handle a high number

of I/O arrangements, which connect to a variety

of sensing devices, as well as actuators that

operate motors or fluid-powered cylinders.”

7

Trends in Technology

What OEMs Don’t Tell End Users About PACsMany end users don’t really know what a PAC is, or what the differences between PLCs and PACs

are. The reality is, OEMs and machine designers need to educate users better

By Don Fitchett, Business Industrial Network

If asked, “Is there really any difference between program-mable logic controllers (PLCs) and programmable auto-mation controllers (PACs),” the machine end user will

likely answer, “No.”Or that person might ask, “What is a PAC?” You may

even get a few that will argue that no difference exists between the PLC and the PAC. Additionally, users may claim the PAC is just a new name and acronym created by the PLC vendor sales department to generate new sales.

The fact is a PAC is very different from a PLC, and it is important for original equipment manufacturers (OEMs) and designers to educate their end users regarding the dif-ferences between a PLC and a PAC prior to purchase and again during customer training on any new equipment.

Machine designers should prioritize educating their cus-tomers on the difference between a PLC and a PAC. Doing so will create significant benefits for both parties by:

• lowering warranty period cost• increasing customer satisfaction.Success in achieving these two benefits is multiplied

when OEMs write programs that provide the appropriate level of detail for end users who might lack prior knowl-edge and experience with PACs. Clear and detailed pro-gram documentation is often more important when using a PAC to control a machine.

There are some major differences and special consider-ations an OEM should take when machine control uses a PAC instead of a PLC. An equal analogy that any equip-ment customer can easily visualize is: A PLC is to a PAC as a digital clock radio is to a computer.

Sure, computers have clocks built into them, but com-

puters are structured differently and, with all the added functionality, are much more complicated than a digital clock radio. The clock/computer and PLC/PAC compari-son can be applied to the intended end-user consideration in PLC/PAC design, too.

See More: PLC vs. PAC ComparisonSimplified, PLCs are designed with the electrician in mind, and a PAC is designed with the IT/computer pro-grammer in mind. With PLC designs, simplicity and us-er-friendliness take priority over functionality. Therefore, the PLC design focuses on ladder logic, which electricians could easily understand from their knowledge of working with electrical diagrams, and the PLC has a very specific control purpose. In contrast, the PAC is designed to han-dle multiple control purposes, not just a PLC, but also a motion controller, a DCS, four additional high-level pro-gramming languages, and more.

The primary purpose of automation control is to im-prove quality, efficiency and uptime. Over the years, PLCs have evolved to serve these purposes well. Nevertheless, the PAC is still greatly lacking in these three areas in cir-cumstances where plant personnel working with PACs are involved in maintenance or troubleshooting the machine or process.

Therefore, it is the responsibility of the OEMs to com-pensate for the PAC’s shortcomings in these areas.

Table 1 shows a side-by-side comparison of the PLC and PAC. The major differences are easily identifiable. Ma-chine designers would do well to consider their end us-ers, who will have to maintain, operate or otherwise work

8

Trends in Technology

with equipment controls, specifically related to important differences in de-vice architecture, ease of access and version control.

Regarding architecture, a PLC has a single scan cycle, and a PAC multi-tasks as a computer does. End users no longer have quick and easy access to the organized data tables that PLC software provided, as the PAC uses only created tags. With a PAC, end users now have to be aware of firm-ware versions, and even access soft-ware revision numbers due to lack of backward compatibility and main-taining current functionality.

There are other drawbacks includ-ing configuration of a PAC, which is much more difficult than it is for a PLC. PLC configuring cards are plug-and-play with the click of a button. PACs comprise several options that often need to be set manually and firmware versions to look for, creating additional complexity.

Some of the most helpful ways an OEM can help their customers to reduce downtime and reduce demand for additional support include:

• recommending training for maintenance specific to PACs and mastery of PLCs before moving on to PACs

• using PAC software’s documentation functionality, such as rung comments, to document in great detail

• abandoning the use of higher level programming lan-guages, such as structured text, blocks and user-de-fined instructions, unless it is required to obtain the desire control and then only where it is required

• carrying over best practices in PLC programming to the PAC programming (cross-reference subroutine, startup subroutine, all HMI in its own subroutine)

• creating a subroutine for key and commonly used processor status data (end users no longer have pro-cessor status data files in PACs, as they do in PLCs, for troubleshooting).

Manufacturers and designers of PACs should make their primary objective to be considering the maintenance and operating personnel who will make minor modifications to the PAC, and they simplify those processes during every phase of the PAC program design. Additional consideration should be given to end users facing stark differences be-tween the PLC and the PAC and to assisting in the aware-ness of disparities in the two systems. Machine manufac-turers should keep in mind during control programming and design that the end users may not be strong in PAC/computer architecture, computer programming knowledge or experience operating them. If they address the end-user needs for the additional level of detail required, they will see less warranty calls and happier customers.

AUTOMATION CONTROLTable 1: Machine designers would do well to consider their end users, who will have

to maintain, operate or otherwise work with equipment controls, specifically related

to important differences in device architecture, ease of access and version control.

9

Trends in Technology

PLC, PAC and IPC StandoffSelecting the best type of controller depends on how you define the technology as well as the

application

By Leslie Gordon

Are there a few key things that OEMs or system integrators say they’ve discovered programmable automation control-lers (PACs) do better than programmable logic controllers

(PLCs) or industrial personal computers (IPCs)? Perhaps not so surprisingly, the answer lies in a grey area, depending on how those in industry distinguish between the technologies.

James Ingraham, software development team leader at systems integrator Sage Automation in Beaumont, Texas, says, “I’m not 100% convinced that PACs are actually a thing because any supplier that sells a PAC sells it to end users that call it a PLC.

Historically, PLCs were, in fact, logic controllers, so they were really good at Boolean on/off, ‘check-a-photo-eye, turn-on-a-motor’ kind of stuff. The addition of servos, PID loops, analog control, communications and database access have complicated the issue. Yet, out here in the real world, we still call it a PLC.”

The IEC 61131-3 standard implemented some years ago defines five languages for controlling devices with a PLC or PAC, explains Ingraham. “The languages are ladder logic, which we all know and love, structured text, sequential function charts, function block diagrams and instruction lists. In addition, a lot of PACs also provide more traditional programming languages like C. That said, an advantage of IPCs is their processing power is vastly more than that of a PLC or PAC. A 12- or 16-core Intel processor with essen-tially unlimited RAM runs circles around a PLC or PAC. So if you have to scale up, that’s probably your best bet.”

In an example of one project, Sage used a PAC to com-bine motion control and database integration with tradi-tional logic control for the just-in-time order fulfillment of tires (Figure 1). “When it comes to end users that are run-ning a bunch of conveyors, for instance, whether they have

an Allen-Bradley shop or a Siemens shop down the street matters a whole lot more than a particular processor’s tech-nical specs,” adds Ingraham. “Most of today’s technology is of relatively equal high quality. More important questions to ask are: where is the support coming from, and which sup-plier do we have the best relationship with?”

PACs Handle Tilt-Tray SortersAnother system integrator has a slightly different take. Pyra-mid Controls in Cincinnati, Ohio, specializes in developing automation solutions to optimize flow, increase accuracy, increase machine uptime and improve the productivity of product distribution centers (DCs).”Over the years, we started calling controllers PACs because they have more ca-pability than traditional PLCs. A PAC or ControlLogix pro-cessor, for instance, can handle servos, all kinds of motion controls and so forth,” says Pyramid’s engineering director, Mark Hegge. “But in our minds, the biggest difference be-tween PC-based controls, PLCs and PACs comes down to the reliability of the equipment.”

In 2012, the firm replaced an outdated PC-based indus-trial control at a major retailer’s distribution center (DC) with a system driven by Allen-Bradley ControlLogix PACs from Rockwell Automation. Many goods sold in major department stores such as dresses, suits, appliances and accessories arrive at the DC in bulk shipments from manufacturers. There, they’re sorted using four tilt-tray sorters and then shipped to hundreds or thousands of retail locations. Packing-sorter ma-chines carry items from the area where workers unload whole-sale merchandise from palletized cartons and place individ-ual items on tilt-tray machines, which feed the items into different chutes, depending on where they’ll be shipped.

The retailer’s legacy PC-based control system was aging

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Trends in Technology

and outdated. It couldn’t properly control the tilt-tray sorters, which are highly sensitive to the timing at which internal switches needed to fire, within 50 ms or under 12 ms. Miss-ing this window could shut the entire sorter down. The re-tailer also needed a technology that could synchronize more than 70 motors on each of the four loop sorter lines, as well as track products to eliminate the problem of lost inventory.

Pyramid replaced the outdated system with several Con-trolLogix PACs—two to control each of four packing loop sorters and one shipping sorter. The controllers are net-worked to the devices on the sorting line via ControlNet, a protocol that provides ongoing feedback to the controller from the system I/O. The controller communicates via Eth-erNet/IP with the Pyramid Director warehouse control sys-tem (WCS) developed by Pyramid. ControlNet and Ether-Net/IP share the common industrial protocol (CIP), which supports the integration of I/O control, device configuration and data collection across multiple networks. The new con-trol system provides advanced diagnostics and analysis of the loop sorter directly to the WCS, so operators are notified of errors. Operators can then call Pyramid for assistance, and it makes adjustments to the system remotely via VPN access.

“The Rockwell equipment is designed for industrial ap-plication and is more robust than PC-based control systems. PC-based controllers are typically upgraded more often be-cause the hardware doesn’t last as long and the software op-erating system isn’t supported as long,” says Mukesh Ram, Pyramid’s general manager. “And, from an end user’s per-spective, the PC requires an IT programmer, as well as an individual with an electrical skill set, to maintain and trou-bleshoot the devices associated with the material handling equipment, whereas PLCs or PACs can be managed by one type of engineering individual—an electrical controls engi-neer. Another advantage of PACs over PCs is they let you do online programming and make changes while the system is running. In contrast, PC programs must be compiled and then executed thus causing interruptions to operations.”

According to Keith Staninger, business manager for con-troller and I/O platforms at Rockwell Automation, a PAC can handle significantly more information than a discrete

machine controller or PLC. “For example, users can imple-ment loop control, predictive control and condition mon-itoring, all of which are different sets of information that make up what we call integrated control,” he says.

PC-Based CapabilitiesOne company that firmly believes in the PC-based control concept is Beckhoff Automation. “Vital to our approach is our TwinCAT software, which runs on PC-based hardware such as embedded PCs to support a wide range of machine automation functions including logic control, motion con-trol and safety,” says Aurelio Banda, vice president sales and marketing at Beckhoff North America. “It, along with our scalable hardware, allows the creation of more centralized architectures, depending on the particular machine and the processes taking place on it, while adding, for example,

TIRES IN MOTION

Figure 1: Sage Automation used a PAC to combine motion

control and database integration with traditional logic control

for the just-in-time order fulfillment of tires.

SAG

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MA

TIO

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Trends in Technology

more motion or safety as needed, without having to rebuild the entire application. The technology uses protocols such as EtherCAT, the open Ethernet-based fieldbus system de-veloped by Beckhoff, and provides data communication with user interfaces and other programs by means of open standards such as OPC UA and various software tools from Microsoft. The embedded PC is therefore attractive from a cost point of view because it eliminates the rigid approach of a PLC in controlling machine processes, which necessi-tates adding more processors, black-box hardware and com-pletely different software packages to provide, for example, additional motion or safety functions.”

Dedicated DevicesAn important distinction between IPCs and PACs is that PACs are normally dedicated to industrial control, where IPCs typically run a Windows OS and may take on other functions, such as running typical Windows applications. “Unlike a Windows system, the PAC OS is real time and often deterministic,” says Jerry Sorrells, product manager

for controls and HMIs in the electromechanical division of Parker Hannifin’s Automation Group. “PLC and PAC tech-nology are converging such that traditional PLC manufac-turers are adding functionality to keep up with PACs. This often includes adding modules for network communication or servo control. This approach, however, increases OEM and end users’ costs by piling on additional hardware. PACs on the other hand are typically designed to communicate on multiple networks and execute multi-axis motion with-out the need for additional hardware. For instance, Parker’s PAC doesn’t require add-on hardware for common commu-nication protocols or servo control, and it doesn’t set an ar-bitrary limit on the number of axes that can be controlled, since the practical limit is a function of the performance required for the application.”

Printing MetalA PAC controls this newly developed additive manufactur-ing machine that uses a unique metal deposition process.

Parker’s PACs have been put to work in applications in-cluding driving 200 axes for a fiberglass machine, as well as controlling a newly developed additive manufacturing machine that uses a unique metal deposition process (Fig-ure 2). Consider the example of Plus Manufacturing, +Mfg, in Erlanger, Kentucky. The designers there are in the final stages of developing a six-axis robotic gantry for 3D metal deposition that uses the new Parker Automation Control-ler to control the building of individual or multiple parts or multiple different parts—each from different metals. “The PAC interfaces with our master computer that delivers the part geometry and takes control of the six axes, so the gan-try and build table follow the motion paths it gives them,” says Paul Saleba, spokesperson for +Mfg. “The PAC pro-vides the six Compax3 controllers inputs and reads outputs interdependently, all while communicating with the master computer to ensure that all the axes work together. The ma-chine, which will be introduced at the Automate Show in March 2015 in Chicago, will be capable of building com-plex metal structures quickly and inexpensively to near-net shape, eliminating the need for casting, welding or forging.”

+M

FG

PRINTING METALFigure 2: A PAC controls this newly developed additive

manufacturing machine that uses a unique metal deposition

process.

12

Trends in TechnologyPACs Analogous to VFDsThe difference between PACs and PLCs can be a grey area, but one of the best ways to understand the distinction is to look at the history, explains Ben Orchard, application engi-neer at Opto 22. “PLCs were a step up from older pseudo-con-trol systems comprising relays and timers, and they were pro-grammed with ladder logic because that’s how electrical diagrams were drawn,” he says. “The whole focus and design of PLCs was digital control of relays. PACs were an expansion of this and much better at handling analog signals and PIDs. Then came the age of networking, originally serial and then Ethernet. With Ethernet communication, PACs kicked into high gear and became the de facto standard for control sys-tems because all it takes is one unit to control, monitor and communicate with multiple racks of analog and digital sig-nals and multiple PID loops.” In short, a PAC can work with devices using analog, digital and serial I/O signals.

“Currently, just about every manufacturing process is becoming more and more analog,” continues Orchard. “A good analogy is that of the variable frequency drive (VFD). In the past, we simply turned a motor or pump on or off, and it ran at full speed. In contrast, VFDs lets device such as pumps be more efficient at different stages of the process by running at different speeds as opposed to flat out.”

In more detail, end user Zuno Engineering of Fort Wayne, Indiana, explains how Opto 22 technology takes a different, yet robust and cost-effective approach. “Our com-pany uses Opto 22 in several ways,” says Adam Brososky, principal at Zuno. “For example we might replace an ex-isting PLC system or a new system where a new machine is being designed, and implement the Snap-PAC controls. Then, depending on the application, we’ll either a install a touchscreen PC for the HMI or Opto 22’s Groov technol-ogy, which is a Web-based HMI that lets users employ an iPad or smartphone to control their machines.”

Better BlacktopZuno replaced all the controls in asphalt plants sold by a local manufacturer.

For example, one project entailed Zuno replacing all the controls in asphalt plants sold by a local manufacturer

(Figure 3). “The manufacturer sells the plants worldwide and wanted its own system and the intellectual property,” says Brososky. “We use Snap-PAC I/O control and monitor all of the points in the plant. This includes the VFDs con-trolling the bins and pumps that proportion the material, controlling the mixing drums, monitoring temperatures of material and keeping inventory control of the output silos. The company’s systems now have a PC that runs as an HMI and communicates with four racks of Opto 22 equipment. Each rack has 16 modules on it, and each module has be-tween four and 16 I/O points. We sell complete systems from building the back panel up to installing the software.”

A big difference between the ladder logic of standard PLCs and the programming structure for Opto 22 is that it’s flow-chart-based with blocks of code. “Many individuals with a classroom-only engineering degree have never seen ladder logic before, but they’re familiar with LabView and C. Opto 22 marries LabView-type programs with C programming in one package. So, for someone who’s never been in the indus-try, it’s a lot easier to use than trying to learn how to program controllers from traditional major suppliers,” says Brososky.

BETTER BLACKTOP Figure 3: Zuno replaced all the controls in asphalt plants sold

by a local manufacturer.

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Trends in Technology

Industrial Controller Programming Top NeedsClosely related to ease of use is the capability to connect instantly and automatically to the target controller

By Dan Hebert

A s industrial control hardware from PLCs to IPCs and everything in between becomes ever more powerful, reliable and similar, purchase decisions are more and

more driven by software, specifically the PC-based software used to program these industrial controllers.

So we asked OEMs and suppliers to give us their must-have programming software features. This column will look at supplier answers, and my Mojo column in December will summarize OEM views.

All suppliers listed ease-of-use as an important feature, but Jerry Reaves, PLC product manager with Automation-Direct, went deeper. “The end user is a beginner, an expert, or most commonly, the perpetual intermediate,” says Reaves. “The perpetual intermediate user interacts with the software on a periodic basis, a profile fitting many OEMs. So if the software is not designed for intuitive use by the intermedi-ate user, then, every time he or she opens the software, new learning is required. When this happens, then no matter how powerful the software is, the user struggles to the point of disliking it.”

Reaves says that intermediate users want easy access to the programming software regardless of the revision. “They want to quickly install the software, connect to the controller and start programming, debugging or troubleshooting,” Reaves points out. “They don’t want to chase different software revi-sions, buy software upgrades or recite software revision levels to technical support.”

Ease of use is also promoted if a supplier has just one con-troller programming software package for its entire line of related products.

“Programming software should be able to target multiple hardware platforms and processor types from a single devel-opment environment. This also should be extendable to new hardware standards such as 64-bit systems and multicore pro-cessors,” explains Daymon Thompson, TwinCAT product specialist at Beckhoff Automation.

Closely related to ease of use is the capability to connect in-stantly and automatically to the target controller. “The ability to quickly and effortlessly establish connection with the PLC for programming and debugging is very important, so we de-

signed our programming software to require absolute mini-mal effort to get the PLC online with the PC-based program-ming software,” notes Don Pham, product specialist at IDEC.

Another widely cited feature is reuse of code. “Code reus-ability and portability are critical productivity factors for many OEMs, as they adopt concepts of modular code design,” says Mike Brimmer, product manager of RSLogix 5000 program-ming software for Rockwell Automation. “Our software offers key features needed to enable modular automation, library management and system organization, including modular coding constructs and the ability to migrate code easily in or-der to reuse engineering efforts.”

If code is to be reused, then version control becomes crit-ical, Thompson interjects. “Efficient use of engineering re-sources through collaboration among multiple programmers lowers development time and costs,” he says. “This can be done by reusing code from previous projects, as well as by us-ing standard source control tools integrated into the program-ming environment, such as Team Foundation Server from Microsoft, GIT and Subversion. Source control tools provide archiving of changes over time, allowing the code to be com-pared, branched/merged and even rolled back. This keeps a history of the code over its lifecycle for future reference and debugging, and it promotes uncomplicated migration of code from one application to the next.”

A final feature cited by multiple suppliers is the capability to program the controller with a wide array of programming languages. “Industrial controller programming software must support different programming languages and styles,” says Mike Chen, pan-America marketing group manager for Om-ron Automation and Safety. “Programming standards should be open, allowing engineers to quickly adapt by using existing knowledge. With the influx of highly competitive industrial components and devices, it’s critical to have open networking and interoperability to minimize incompatibility.”

In short, suppliers say the top five controller programming software features are ease of use, automatic connection to the controller, one programming package for an entire family of controllers, the ability to reuse code and support for multiple programming languages.

15

Trends in Technology

Is PLC a Dirty Word Now?Controllers now are called PACs, industrial PCs, or just about anything else except what they re-

ally are

By Dan Hebert

Just a few years ago, every controller vendor touted its PLCs, and machine and robot builder OEMs echoed the theme when discussing automation fea-

tures with their customers. But past affection for PLCs is now the love that dares not speak its name — as con-trollers now are called programmable automation con-trollers (PACs), industrial PCs, or just about anything else except PLCs.

Changing names sometimes is just about marketing hype, but not in this instance. Virtually every modern machine, robot or motion controller employs multiple technologies directly borrowed from the commercial PC world. This makes the modern controllers more like PCs, and a lot less like PLCs.

For a variety of reasons, chief among them installed base, major U.S.-based vendors were among the last to relinquish proprietary PLC technology and move to the PC world. On the other hand, vendors based in Europe, particularly in Germany, were among the first to jump on the PC bandwagon.

“Beckhoff follows the technology migration set by In-tel and adopts the latest processors for industrial use.

We offer industrial PCs that use second-generation In-tel Core i3, Core i5 and Core i7 processors in a rugged plant f loor-worthy housing,” says Graham Harris, pres-ident of Beckhoff Automation. “For machine builders and robot builders, this adds functional layers in soft-ware rather than via separate hardware boxes.”

When Wago describes its current controller offering, it does so using PC and IT terminology. “Our Ethernet 2.0 platform provides modularity, scalability and high performance,” notes Charlie Norz, product manager of I/O systems for Wago. “Gen II of our Wago-I/O-System Ethernet 2.0 packages those attributes with higher-per-formance processors into three distinct and compact programmable fieldbus controllers (PFCs). For network-ing/control f lexibility, OEMs can choose features like

“ Controllers now are called programmable auto-

mation controllers (PACs), industrial PCs, or just

about anything else except PLCs.”

16

SD card capability and network redundancy, and all our PFCs have a dual-port Ethernet switch to support dai-sy-chaining.”

Like Wago, Phoenix Contact uses PC technology to greatly reduce form factors, providing DIN-rail mount-ing capability. “Our ILC 100 class controllers feature an integrated web server and function block libraries for IT-friendly functionality,” notes Dan Fenton, control and software product marketing specialist at Phoenix Con-tact. Technologies borrowed from the PC world such as SNMP and web-based HMIs further enhance connec-tivity and communications.

Rockwell Automation didn’t invent the PLC, but it certainly was a leader in promoting its use in machine automation. But when it comes to making the term PLC verboten, it ’s et tu Rockwell. “Our ControlLogix PAC enables a manufacturer to integrate motion, safety, se-quential, drive and process control to provide a high-per-formance control solution,” says Mike Burrows, a direc-tor at Rockwell. “One common Ethernet layer allows the integration of plant information with enterprise systems, using standard Cisco technology for security. The Com-pactLogix controller gives machine builders integrated motion on EtherNet/IP.”

Although larger U.S.-based PLC vendors were rela-tively slow to jump on the PC train, smaller suppliers were onboard early. “Our SoftPLCs are open-architec-ture PACs, running ladder logic as their primary lan-guage, but also supporting C++,” explains Cindy Hol-lenbeck, vice president of SoftPLC. “SoftPLCs have advanced PAC features such as data logging, database interface, advanced math calculations, email/texting and other communications, and more. The SoftPLC runtime engine is a Linux-based kernel that runs on an embedded computer such as an x86-, ARM- or Power-PC-based system.”

Opto 22 has long championed Ethernet-based I/O, along with other technologies from the PC world such as task scheduling and distributed processing. “Unlike with a PLC, individual tasks can be scheduled and ex-ecuted more logically with our Snap PAC and its f low-chart-based control programs,” says Selam Shimelash, application engineer with Opto 22. “If some of the ma-chine I/O is less critical and doesn’t need to be scanned as often, the control program can be designed and writ-ten that way. The PAC won’t communicate with the I/O unless it needs to because the scanning of I/O points is a task performed by the remote brains.”

Trends in Technology

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Combine Control and Operator InterfaceThe upsides and downsides of contoller-display combo units

By Dan Hebert

A combo controller and operator interface can save big compared to separates.

As the miniaturization of electronics continues its relentless march across the personal-consumer-device landscape, it’s only natural for it to proceed apace in ma-chine and robot automation systems. One consequence is the combination of what were once separate compo-nents into a single housing, as with a machine controller and an operator interface device.

Although relatively new on the scene, these combi-nation units have seen significant adoption by machine builders because they are less expensive than separates, require no wiring or integration between the controller and the operator interface and take up less panel space.

For many applications, these benefits more than ne-gate disadvantages, which include a single point of fail-ure for both control and operator interface and a lack of the highest-end functionality, particularly for basic units.

These combination units come in two main f lavors. The first one combines a PLC with an operator inter-

face terminal (OIT) to create a unit designed for basic machines. The second marries a PC-based controller to a full-featured HMI, creating a unit capable of provid-ing control and operator interface for the most complex machines.

Combo PLC-OIT units were initially introduced with limited features and functions, but more recent products have upped the ante by adding more sophisticated capa-bilities. “The newest addition to our FT1A Touch mi-cro programmable controller series of combo HMI+PLC units is the FT1A Touch 14 I/O, with new features mak-ing it suitable for advanced analog monitoring and con-trol,” says Don Pham, a product manager at IDEC (www.idec.com).

“The FT1A Touch 14 I/O provides up to 158 discrete and analog inputs and outputs, using FT1A controllers as remote I/O slaves, PID control, Ethernet communica-tions and a built-in 3.8-in touchscreen HMI in a compact package costing less than $500,” adds Pham.

This is obviously an attractive price point, one hard to

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match by purchasing a separate PLC and an OIT, partic-ularly when the cost of wiring, integrating and installing two separate units is taken into account.

A bit higher up the scale in price and performance, starting at about $1,000, is the Perspecto CP TV line of combo units from Wago (www.wago.us). These units feature five sizes of TFT touchscreens: 3.5, 5.7, 10.4, 12.1 and 15 in. “Performance is optimized with scaled processing power up to a 1.6 GHz processor, 256 MB of RAM and 128 MB of Flash memory,” notes Charlie Norz, the product manager for WAGO I/O Systems.

“Our combo units are programmed using CoDeSys software, providing advanced programming tools, sup-port for all the IEC 61131-3 programming languages and an easy-to-use graphic editor,” notes Norz. These units also have multiple interface ports, including CAN bus and Ethernet, and a built-in Web server that allows re-mote users to view and control the graphic screens using any browser.

These combination units can be a good fit for machine builders who are not requiring large HMI-type screens, hundreds of I/O points or advanced control functionality. For applications requiring those features and functions, the next step up the line are combo PC+HMI units.

Readers over 40 years old may have not-so-fond memo-ries of the sheer size, bulk and weight of older PC-based control systems.

Not only was the CRT-based screen a monster, so was the industrial PC. Add in some outboard I/O, and the en-tire package was cost- and size-prohibitive for all but the most high-end applications.

But times have changed, and new units simply tack a PC-based controller onto the back of a f lat-panel screen, creating a slim panel-mount package with reasonable weight and not much more depth than a monitor alone.

A pioneer in this area is Beckhoff Automation (www.beckhoff.com) with its panel PCs. “Rather than recom-mending a multi-component solution with separate PLC and HMI hardware, we offer customers an all-in-one ap-proach combining an industrial PC and HMI, packaged as a streamlined panel PC,” explains Reid Beilke, the in-dustrial PC product specialist at Beckhoff.

“These units offer multicore processing performance, multi-touch functionality and customizable housings. When running our TwinCAT software, one multi-task-ing panel PC can handle the work of multiple PLCs, while also performing motion and robotic control,” adds Beilke.

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What Exactly Is a PAC?Does it matter whether you use a PAC from a PLC vendor vs. a PC-based control supplier?

“ We’ve used basic PLCs and I/O for machine control for a long time. Our machines have to do more than before, and we need more connectivity options and a more COTS, standards-based approach to hardware and programming. Some customers are on the PAC bandwagon and think it’s the next step for them and us. There are different opinions of what a PAC is. PLC vendors say they make PACs. So do PC-based control suppliers. Does it matter?”

—FROM AUGUST ‘12 CONTROL DESIGN

AnswersMASHUP CONTROLA programmable automation controller (PAC) can be de-scribed as a “mashup” between a PC and a PLC in that it typically offers the benefits of both in a single pack-age. Therefore, it’s becoming more common that PLC vendors position their higher-end controllers as PACs — largely because their higher-end products incorporate more connectivity options and broader control capabili-ties than their PLC lines.

In your situation, the key point is what you state in your question: connectivity options and commercial off-the-shelf (COTS) technology. PACs offer both out of the box. Connectivity options like Ethernet are standards-based and therefore deliver on the COTS promise. For exam-ple, standard, readily available components like network-ing hardware will more easily and cost-effectively inter-face with a PAC.

In contrast to PC-based control, more often than not,

a PAC will have lower running and maintenance costs. One advantage of a PC-based controller is faster comput-ing speed and greater data storage area, but not necessar-ily faster I/O access. Will your machine accommodate a larger PC-based controller? Is the environment around the machine harsh in any way? PACs are usually smaller and more robust.

Taking all this into account, you must consider your customer requirements, weigh in your machine con-straints, and choose the best upgrade. Many options cer-tainly exist, and ideally, you should choose a vendor that provides multiple controller options (both PAC and PC-based for example).

Given the rising use of smartphones and tablets in in-dustrial automation, you should also be looking at a plat-form that will ease adoption of this technology into your machine. Internet, wireless and cloud-based storage solu-tions are all growing in use. Select a PAC, PLC or PC that can support these technologies and protocols in a secure manner.

So, does it matter? Yes, I believe so. But, it’s your current and future customers that will ultimately help you decide.

BEN ORCHARD, systems engineer,

Opto 22, www.opto22.com

THE ONE THAT SUITS YOUR NEEDSPLC is a term generally used to describe a general-pur-pose controller ideal for controlling standalone, discrete machinery or processes. A PAC refers to a controller that offers multi-discipline control. For example, a PAC might

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offer the ability to execute complex motion instructions as well as possess integrated safety functionality, while a PLC typically would offer only logic control.

Some PC-based control suppliers might offer PACs, but not all PC-based controllers are PACs. The terminol-ogy is often interchanged, even among the most savvy machine builders.

Here are some questions to help guide you:1. Does your application require multi-discipline con-

trol (motion, safety, drive, process, etc.)?2. Do you have panel size constraints that should be

considered?3. What is the expected lifecycle of the machine?4. Is rugged packaging required?5. What networks will you be using for your machine

design?Overall, the terminology is less important than select-

ing the controller and vendor partner that best meet your specific needs.

DEXTER LEONG, product manager, CompactLogix,

Rockwell Automation, www.rockwellautomation.com

A CONTROLLER BY ANY OTHER NAME…I think the concept of a PAC, while technically defined, is more of an all around automation “solution” piece of hardware, rather than the simple I/O controller we’re used to in PLCs. It used to be that the control system ended with the PLC, and users interacted with an HMI to report this to the office, where the numbers were punched in again. Then we added SCADA, and had to move information out of the PLC and into a more PC-based environment.

It’s inevitable that the next step of control systems would be to integrate a more tight-knit linkage with the systems where the information needs to f low, and often that information needs to f low to an IT-controlled sys-tem. So really, I think PLCs are becoming the less-ex-pensive alternative to a PAC and becoming PACs in all but name, and PC-based control systems are “hiding” their PC background and moving toward a form factor and user interface much more akin to the traditional in-terfaces we’re used to in the controls industry. Really, I don’t think it matters.

What does matter is that you find the proper tool for the job, and more and more we’re seeing connectivity options increase across the board. Standards-based pro-gramming gives us the ability to teach the next genera-tion of controls engineers how to program independent of manufacturer, and often to pick and choose what lan-guage is the best for the particular programming option. It’s an exciting time to be in this industry!

DAN FENTON, control and software product marketing,

Phoenix Contact, www.phoenixcontact.com

OFTEN NOT REQUIREDThe “Real Answer” is that is doesn’t really matter. PAC is simply a term used by some suppliers to describe what others would call PLCs and PC-based controllers. In general, it refers to hardware that goes above the simple ladder logic found in classic/basic PLCs, and that can in-corporate higher-level control such as PID and sequence control.

Nowadays, the majority of PLCs offer this higher level of functionality, with standard programming languages,

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connectivity for multiple bus systems, and functional expansion through add-on modules. PC-based systems offer similar functionality, with a PLC kernel and ad-ditional interfaces to allow integration of standard PC technology and peripherals.

PACs often offer a higher level of performance, inte-gration of higher-level PC languages and visualization possibilities combined on one system. This convergence of technologies provides benefits of consolidation of tasks into a single system, but brings with it an inherent increase in complexity.

In the end, today’s PC-based and PLC offerings can both handle most applications. The one that is right for you depends on your specific application, functional re-quirements and knowledge. Both types of systems come off-the-shelf with industry-standard communication and engineering, and offer enough f lexibility that proprietary solutions are far more costly and often not required.

SYDNEY MCLAURIN JR.,PC-based automation marketing manager,

Siemens Industry, www.usa.siemens.com

SOME THINGS MATTER, SOME DON’TThere certainly are varying definitions of what a PAC exactly is vs. the traditional PLC. As a machine builder, the primary concern shouldn’t be in the terminology. Instead, consider other aspects when faced with hav-ing to add the features listed in the question. What level of functionality and performance is required for con-trolling a particular application? Is there an automation platform available that can offer right-sized and cost-ef-ficient hardware for not just a single machine, but an entire machine portfolio? Can the automation platform

easily be customized with off-the-shelf products to adapt to changing needs and can it do that while reusing any existing application software? Is the hardware and soft-ware built on a modern architecture that ensures both innovation and long-term availability?

From my perspective, the main difference between a PAC and PLC is that a PAC provides better control of the timing of the application program(s) that run on the controller. In a PLC, the program typically runs in a con-tinuous mode, meaning that as soon as one scan finishes, the next one starts. The advantage is that small programs run fast even on low-end hardware, but as the program grows, so does the program runtime, thus slowing down reaction times. Another disadvantage is that as different program conditions execute more or less code per scan, the program execution time varies, leading to inaccura-cies that will have a negative impact on the repeatability from one machine or product cycle to the next.

On a PAC, the program will run in a scheduled cyclic mode. Here, an underlying real-time operating system will schedule program(s) in cyclic tasks with different priorities and cycle times independent of the program ex-ecution time. This allows the application to be separated into programs running in a fast cycle time for time-crit-ical tasks (e.g. digital I/O processing) and slower cycle times for less time-critical tasks (e.g. PID temperature control and HMI logic) on the machine. What might look more complex at first really offers much greater f lex-ibility to any machine builder in designing the applica-tion software and achieving better production accuracy and repeatability due to a constant timing.

Another common difference between a PAC and a PLC is the ability to incorporate additional functionality

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like motion and robotic control, remote or onboard vi-sualization, file handling, web server, etc., on the same piece of hardware, allowing consolidation of multiple controllers into a single one and offering value-adds in terms of diagnostics and data collection capabilities.

This is the area where the lines from PLC to PAC and PC begin to blur depending on what functionality the underlying hardware and operating system architecture of the controller allows. Some manufacturers are using microcontroller- or RISC-based architectures, which are in essence a “PLC on steroids” — faster and with better timing but not too much more functionality common in a PC-based architecture.

Some PC manufacturers come from the other end — taking an industrialized PC with a real-time operating system and maybe a second OS like Windows and calling it a PAC or “soft PLC.” Such systems offer great perfor-mance and additional functionality, but can’t necessar-ily be scaled down cost-efficiently for lower-end applica-tions because of the PC hardware overhead. They might also lack features common in a PLC like non-volatile memory to retain tag information through a power cycle.

ROBERT MUEHLFELLNER,director of automation,

B&R Industrial Automation, www.br-automation.com

PAC OR ENHANCED PLC?It doesn’t really matter what you call the controller; the real issue is the functionality you need and how much are you willing to pay for it. PLCs have been enhanced with extra hardware and software over the years to han-dle more than their original function of sequential logic. PACs were introduced as some companies saw a more

cost-effective way to handle motion control, visualiza-tion, more advanced calculations, and connectivity to supervisory and ERP/MES systems.

These alternative suppliers to traditional PLC vendors re-alized that they could provide all of these extra functions without the extra cost of additional hardware and software by using a powerful industrial PC processor as the core of their controller. These powerful devices were called PACs at first to differentiate them from “enhanced” PLCs.

Unfortunately, some PLC vendors answered this de-velopment by calling their enhanced PLCs “PACs” as well, leading to confusion with the term. While PC-based solutions use standard, off-the-shelf technologies and manage more functions in software, the PLC-based PACs tend to rely more on proprietary add-on hardware.

Again, you must look at the cost and functionality you need, and choose the best technology for your applica-tions. In general, you will get more advanced function-ality, higher performance and a lower cost if your con-troller uses a PC-based design, as it can handle all of the tasks within one CPU and with one software package. On this note, the advent of multicore processor technol-ogy in PC-based control technologies has given a consid-erable lead to the controllers that incorporate them over their traditional PLC-based peers. Also consider that less hardware and software is normally a good engineering principle for improved lifecycle management.

The most important consideration is how it can de-liver enhanced functionality while also having the best price-to-performance ratio.

GRAHAM HARRIS,president,

Beckhoff Automation, www.beckhoffautomation.com

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Back to Basics

A PLC by Any Other NameA PAC is a PLC on steroids. Anything a PLC can do, a PAC can do

By James Ingraham

A PLC implies control of discrete signals. PLCs, how-ever, evolved long ago to handle more than just on/off sequences. Math functions, PID loops and even mo-

tion control now are handled by one processor, which has led to the advent of the programmable automation control-ler (PAC). Having distinct terms separates the classic on/off control of PLCs with the modern all-in-one approach, but fundamentally, a PAC is a PLC on steroids. Anything a PLC can do, a PAC can do.

So, is there a place for the traditional PLC? In a word, yes. Many applications really are just on/off logic. With microprocessors pushing size down, even smart relays can execute ladder logic.

Programming language is another area of distinction be-tween the two controllers. PACs generally can handle any of the IEC 61131-3 languages, namely relay ladder logic, instruc-tion list, structured text, sequential function chart and function block diagram. Some PACs can be programmed in other lan-guages as well, even in ‘real’ programming languages such as C.

The idea of the PAC is to take advantage of decades of im-provement in computing power to give automation profession-als multiple tools in one platform.

Another advantage of PACs is their tendency to have more memory than traditional PLCs. This isn’t necessarily a limita-tion of PLCs, just a reality of the market. Coupled with math functions, this can allow PACs to grab data that was once the domain of the HMIs and SCADA systems—for example, keep-ing a log of a measurement, along with the average, standard deviation and histogram data.

Sophisticated ASCII string manipulation also is useful for preparing messages for the HMI. This opens up new oppor-tunities for measuring performance of systems. Data can be kept at the controller level, giving finer-grain control and more precise measurement. This data can be time-stamped and hu-man-readable, ready to ship up to the HMI as a simple string.

Motion control isn’t necessarily an inferior bolt-on. Elec-

tronic line shafting, camming and even six-axis kinematics are available on some PACs. Advanced motion control in lad-der logic or another language often is easier for end users to support and troubleshoot than traditional stand-alone motion controllers would be. Likewise, auto-tuning, trend graphing or other built-in augmentation to straight PID loops can make life a lot easier in certain instances.

Still, for all of the advantages the PAC has, there are times when it’s overkill. This is particularly true at the low end of ap-plications, with a handful of discrete I/O points and control of simple machinery. While PACs are coming down in cost, they still cost thousands of dollars, whereas simple PLCs are in the hundreds. The programming software for low-cost PLCs also is much less costly than programming software for PACs. This difference can be substantial when you consider the cost of en-abling every technician to go online to troubleshoot equipment.

The line between what a PAC is and what a PLC is never-theless remains quite blurry. When exactly is the jump made between a high-end PLC and a low-end PAC? In the end, the distinction is less about naming convention and more about application needs. ‘Do I need a PAC or a PLC?’ is not the question. ‘What functions do I need for this application?’ is the proper place to start.

A straightforward conveyor application is probably best-suited to ladder logic and, on the surface, doesn’t need more than discrete control. However, even a conveyor system might have barcode scanners, encoders and other sophisticated de-vices with which traditional PLCs don’t necessarily work well. A conveyor system able to make on-the-fly product changes might even need motion control.

In the end, deciding whether to use a PAC, a PLC or some other automation controller hasn’t gotten any easier. There are just more options. Look at the application, see what’s re-quired, and get the best fit. Increasingly, devices marketed as PACs are the obvious choice.

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Back to Basics

Five Must-Have Controller Programming FeaturesMachine builders want ease-of-use, support for multiple programming languages, ability to re-

use code, global acceptance, and the ability to accommodate motion and robotic control along

with traditional PLC functions

By Dan Hebert

What are the most important programming soft-ware features? In my previous column, I shared the supplier voice on this question, and this one

shares what OEMs have to say. The five features listed as most important by suppliers were ease-of-use, automatic connection to the controller, one programming package for an entire family of controllers, ability to reuse code and support for multiple programming languages.

Machine and robot builders agreed with suppliers on three of these five features—ease-of-use, support for multiple programming languages and ability to re-use code. However, the OEMs listed two other features of greater importance to them—global acceptance and the ability to accommodate motion and robotic control along with traditional PLC functions.

Ease-of-use covers a wide range of attributes expressed by Mike Roth, electrical controls engineer for auto-mated packaging equipment builder Massman Automa-tion. “Flexible tag naming, array structures, motion in-structions and PID instructions should be available and well supported in the programming environment with

online help and concise information pertaining to com-pilation errors. Features such as drag-and-drop, cut-and-paste and autofill fields all help reduce programming time and errors,” explains Roth.

Daren Myren, controls engineer at packaging system suppler Aagard, says programming software should have these three ease-of-use features—programming that’s easy to navigate and search, responsive communication with the PLC/PAC while online and trending/scope ca-pabilities to monitor tag values and transitions.

Support for multiple programming languages is im-portant to OEMs and suppliers alike, as is the closely re-lated feature of support for a wide variety of instruction types. “At minimum, programming software should sup-port ladder logic, structured text and sequential func-tion charts (SFCs),” says Kevin Alexander, unified sup-port manager for Bastian Solutions, a material handling systems integrator.

“For machines operating very sequentially, SFCs provide a very robust and streamlined method for con-trolling a sequence of operation, while providing easy

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troubleshooting. Structured text is best for program-ming communication sockets as it ’s much cleaner and more efficient than ladder logic. A wide variety of pre-built instructions allows a programmer to mitigate com-plexity and streamline code, and custom-built instruc-tions that can be reused within the code should also be available,” adds Alexander.

As Alexander notes, a wide variety of instruction types allows for scalability and reusability, a third feature im-portant to OEMs. “Software that works for a variety of platforms allows a programmer to generate standards that can be used from project to project, improving reli-ability and allowing for much quicker implementation,” concludes Alexander.

A feature cited by OEMs but not suppliers is global acceptance by the customer base of the software and its supported controllers. “The software must be glob-ally accepted and utilized by factory managers, engi-neers and technicians,” says Roth. “End users must be able to extract production data, make program changes and troubleshoot factory f loor equipment. Poor perfor-mance, downtime and uncertainty can be attributed to the lack of availability, familiarity or ability to use PLC/PAC programming software. Rockwell Automa-

tion has an extensive distribution and support network in the United States and Canada. Because of this, most of our North American customers either mandate or readily accept equipment with their control platforms and programming software. It’s apparent that Rockwell Automation has also made gains in Europe because of an increase of the acceptance of its use with Massman’s customers outside North America.”

Roth says the final feature of importance is the abil-ity to accommodate PLC, motion and robotics. “Hav-ing to learn just one programming software package for multiple automation disciplines increases efficiency and creates an environment that brings an automation team together. Time and energy can be spent on the automa-tion task at hand versus learning multiple software pack-ages,” notes Roth.

“Massman has a partnership with a well-known ro-bot manufacturer because their hardware can be pro-grammed and controlled via a Rockwell Automation control platform. A single programming software/lan-guage for multiple disciplines improves reliability, sup-portability and control simplicity, and it also allows in-formation to be seamlessly shared between the PLC, motion axis and robot,” explains Roth.

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Back to Basics

Controller by Any Other Name Programmable automation controllers are real. Just don’t expect a clean definition. Concern

yourself with how they can help you

by Joe Feeley

In recent years, machine builders and users have strug-gled to get a clear understanding of what a programma-ble automation controller (PAC) is, particularly since

descriptions of these devices vary among automation sup-pliers.

More importantly, they want to know how a PAC solu-tion might help them in ways that a traditional PLC or PC-based control system can’t—or can do only with costly, messy and time-consuming add-ons.

What the hardware/software solution is called is not very important to two machine builders we’ll tell you about in this article. It’s the performance enhancements they enjoy compared with the older PLC or PC-based control solutions that matter. Some of this enhancement provides a competitive advantage, and some is a means to satisfy customer needs as they develop more data-collec-tion requirements.

From PC to PACFor 15 years, the Aagard Group (www.aagard.com) has designed, engineered and built automated packaging ma-chinery in Alexandria, Minn., including integrated and standalone flexible form fill seal packaging machines, wrap-around cartoners, endload cartoners, sleevers, retort loading/unloading systems, case packers, tray packers and palletizers/unitizers.

“We used a PC-based control system with a Sercos bus for all our product lines for about eight years, before mov-ing to what Rockwell Automation calls one of its PAC solutions,” says Daren Myren, Aagard controls engineer.

Myren also is Aagard’s Rockwell Automation Platform Manager across all the company’s machine lines. “At that time, there weren’t any PACs or PLCs out there that could handle our demand—40 to 50 Sercos axis counts and keep the processing time reasonable—with just one controller. The driving factor to switch to a ControlLogix L7 platform about two years ago was that we now could control up to 32 axes on one controller and still maintain our performance.”

Another major factor was too many failures on the PC-based system. Myren says it was a more-fragile system. “Plants wouldn’t know exactly how to handle security updates, and some of them could cause issues with our control system and sometimes shut the machine down,” he adds. “Since we’ve been using the PACs, I’m not sure we’ve had even one PAC failure.”

When the machine automation scheme was PC-based, Aagard developed and integrated a lot of remote ac-cess connectivity technology by itself. “We wrote a lot of software for data collection,” Myren recalls. “We put the PC right on the server to remotely access and con-trol the machine. Because a lot of our customers have a Rockwell-based data-collection system, our move to ControlLogix allowed us to use the PAC data and com-munications capability directly with the customers’ da-ta-collection systems.”

The move to a PAC architecture wasn’t a big concern for Aagard’s customer base. “Our customers really didn’t know the PC-based system very well,” Myren explains. “But at that time they knew that we couldn’t handle the

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higher axis count with a PLC or, if we did, it was going to cost a whole lot more. The PAC is a way for us to provide that same functionality at reasonable cost, and the cus-tomers were comfortable with the Rockwell brand.”

The Do-All Control PlatformThe supplier community earnestly does its best to posi-tion its version of what a PAC is.

“Our PAC is a multi-discipline device that incorpo-rates more than just PLC functions, motion, process and safety,” begins Dennis Wylie, product manager for the

Rockwell Automation (www.rockwellautomation.com) ControlLogix platform. “It brings in more direct commu-nication with databases, multiple field networks, and en-terprise-level networks.”

Wylie says it’s becoming more of a server-class device that is a do-all control approach for everything except smaller, simpler installations that just don’t need it all. “But we’re scaling that, too,” he adds. “Even the smaller CompactLogix devices have some of this capability built in for when you just don’t need $25,000 worth of database in-tegration or $25,000 of historical data logging capability.”

B&R Industrial Automation’s (www.br-automation.com) stand on what a PAC-type solution looks like these days is that the primary concern shouldn’t be in the terminology. “A main difference between a PAC and PLC is that a PAC provides better control of the timing of the application programs that run on the controller,” says Robert Muehl-fellner, director of automation at B&R Industrial Automa-tion. “On a PAC, the program will run in a scheduled cy-clic mode. An underlying real-time operating system will schedule programs in cyclic tasks with different priorities and cycle times independent of the program execution time.” This, Muehlfellner argues, allows the application to be separated into programs running in a fast cycle time for time-critical tasks such as digital I/O processing, and slower cycle times for less time-critical tasks like PID tem-perature control and HMI logic on the machine.

“Another difference between a PAC and a PLC is the ability to incorporate additional functionality like motion and robotic control, remote or onboard visualization, file handling, web server, etc., on the same piece of hardware, allowing consolidation of multiple controllers into a sin-gle one and offering value-adds in terms of diagnostics and data collection capabilities,” Muehlfellner says.

Rockwell Automation doesn’t play favorites about whether a PAC approach is better suited to PC-based con-

KEEP IT MOVINGAs part of a continuous-motion cartoning system, Aagard’s

new robotic infeed module is ideal for handling a variety

of components that are difficult to feed in other ways. The

module is a one-of-a-kind design that uses a midrange PAC

architecture system.

AA

GA

RD

Back to Basics

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trol users vs. PLC users. “This really defines the hybrid controller space,” Wylie contends. “We have PAC users who were accustomed to the PLC, ladder logic-driven solution. Likewise, former higher-end PC-based users like the standards-based languages and communication capabilities they had.”

A PAC might not be where you need to stream YouTube videos, Wylie says. “But it does I/O control well. A PC can do that, but it’s certainly not its strong suit. But former PC users like the idea that they don’t have to worry about as many security patches.”

After PLCsG.A. Braun (www.gabraun.com), based in North Syra-cuse, N.Y., makes large industrial-grade laundry and tex-tile equipment. Its multi-chamber, tunnel-style washers can process up to 8,800 lb of laundry per hour. The com-pany has operated since 1946.

“The individual machines have their own control sys-tems, but we can link the washers, dryers, conveyance sys-tems to operate as one system because we can connect them via a SCADA package we wrote ourselves in Lab-View,” explains Matt Fenn, lead software engineer for Braun. “The SCADA system turns them from individual machines in an automated system.”

Braun and B&R Automation go back some 30 years, and the machine builder migrated through what Fenn calls B&R’s “blackline” traditional rack-based PLCs “with a CPU card, input and output cards, and all programmed in ladder logic with a little assembly language in there and a few of your own function blocks.”

Later, Braun migrated to B&R’s System 2003 CPUs and I/O. At that time, Fenn says, it was called a programma-ble computer controller (PCC), which still was most like a PLC, but began to have some of the capability that now defines what a PAC might be.

“One of the big differences was the Windows-based de-velopment environ-ment they supplied,” Fenn adds. “It al-lowed us to have dis-tributed I/O on or be-tween machines with CANbus, whereas machines using the old approach were pretty much hard-wired.” Fenn says he liked the improved f lexibility as well, and the company be-gan programming in C. “Now, if I wanted to talk Modbus out of a serial port, I could do that in software without having to buy special-ized hardware.”

Muehlfellner adds, “What might look more complex at first really offers much greater f lexibility to any machine builder in designing the application software and achiev-ing better production accuracy and repeatability due to a constant timing.”

The migration continued to a solution based on B&R’s touchscreen visualization and PLC with a real-time OS in one platform, the Power Panel 420. “The Automation Studio development platform was backward-compatible, allowing us to pretty easily port the 2003-based program-ming to the new hardware offering,” Fenn says. “That helps us take advantage of higher-end hardware capabili-ties without rewriting our programs.” According to Fenn, at least 95% of the machines Braun sells today are based on this platform.

CONNECT THE PACS Washnet HMI/SCADA software con-nects all of Braun’s PAC-controlled equipment and provides plant opera-tors access to real-time data to monitor equipment, manage formulas and view equipment alarm and production history. It also lets technicians remotely support technical needs.

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Customer Support“The amount of time we spend working with our custom-ers on automation issues has decreased,” Aagard’s Myren says. “We don’t get as many calls in part because they can troubleshoot a Rockwell system themselves instead of de-pending on our expertise with the PC-based system.”

Fenn hasn’t found reasons yet to use the IEC 61131-3 lan-guage options available to him, since for now, the team is comfortable in C. But he sees a few important hardware ad-vantages that impact customer support. “The entire applica-tion now is stored on compact flash, whereas on a traditional PLC, our application was on the CPU in memory chips,” he explains. “So if I wanted to do a software upgrade, I would have to send out a set of chips, which usually wasn’t practi-cal, so you had to replace the CPU or flash it onsite with a laptop, or get somebody to try to pull off an EPROM and replace it, which was pretty tricky. So now, I just burn a new compact flash drive, and send it to the company’s technician who just swaps out the flash drive.”

The networking diagnostics are great as well, Fenn says. “And that’s something that we couldn’t do before this up-grade. I can connect all these machines over Ethernet, and through our SCADA package, go in and update any of them without the need for the flash-drive exchange. During commissioning, it’s very handy, since I can moni-tor the variables on the controller or see an on-site instal-lation software issue from here in my office, and go into the controller and fix the problem via the SCADA PC.”

What’s Next?“Going forward, this PAC solution will offer things we previously had to develop ourselves for PC-based control, like change-logging and other security aspects of the sys-tem,” Myren says. “We’re seeing some of this and even more coming out in newer Rockwell releases. We can get these as a module that plugs into the control rack or as a software plug-in instead of having to write it ourselves.”

Wylie says that the means to secure a PAC compared with securing a PC is becoming a major topic for every customer moving forward, given recent world events, and Rockwell is putting these threads of security in at the core, the chip level of these control architectures.

As to where a PAC-like environment will take his com-pany’s machine control abilities in the future, Fenn is evaluating the newest version of the Power Panel. “In-stead of doing the visualization through the Automation Studio, it runs Windows Embedded on top of the RTOS,” Fenn says. “That gives us the flexibility to write our vi-sualization with .NET and leverage some third-party Windows software. I could put a SQL database on the machine so it can do its own data collection, enable pre-ventive maintenance databases, and I even can show re-pair videos on the machine.”

Fenn continues, “We’ve come such a long way from original proprietary control software that was written by an ex-employee. The technology changes so fast that we can’t be spending time away from our core business by having to write software and build our own hardware. We can ride the train of commercially available solutions and grow our capabilities that way.”

The lines from PLC to PAC and PC blur depending on what functionality the underlying hardware and operating system architecture of the controller allows. “Some manu-facturers are using microcontroller- or RISC-based archi-tectures, which are in essence a ‘PLC on steroids’—faster and with better timing but not too much more functionality common in a PC-based architecture,” Muehlfellner states. “Some PC manufacturers come from the other direction by taking an industrialized PC with a real-time operating system and maybe a second OS like Windows and calling it a PAC or ‘soft PLC.’ Such systems offer great performance and additional functionality, but can’t necessarily be scaled down cost-efficiently for lower-end applications because of the PC hardware overhead.”

Back to Basics

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Back to Basics

The Many Faces of PACsHow PACs are defined isn’t as important as what each version can do

By Jim Montague

The precise nature of programmable automation con-trollers (PACs) appears to be in the proverbial eye of the beholder. Some developers say they’re souped-up

PLCs with more processing power, while others say they’re a genuinely different, more software-based animal. How-ever, everyone agrees that how PACs are defined isn’t as important as what each version can do.

“PAC is a term coined to differentiate from PLCs that tra-ditionally had more rigid functions and lacked data connec-tivity,” says Graham Harris, president of Beckhoff Automa-tion. “So PACs are typically controllers that can allow logic and motion processing to happen in the same space. We say a PAC is a PLC-plus that comes in different shapes. We used to talk about data flowing though companies from sensors to the boardroom. Well, the Internet of Things (IoT) or Indus-try 4.0 is here now. The real revolution is in making more of these connections and further linking devices and facilities to overall operations. That’s the true value of PACs.”

To nurture these connections with multi-core processing, Beckhoff is running four core chips in the CX 2000 embed-ded PC it released last year. This device looks like a PLC or PAC, but Harris says it’s closer to four controllers in one and can run high-speed sequential control, high-speed mo-tion, HMI, vision, data connectivity and other applications on separate cores. “Running multiple cores and devices on a common database means better coordination and faster control because the devices can quickly reach in and grab whatever they need, and this is a big IoT enabler,” he adds. “It’s just like all the handheld PCs, phones, beepers, cam-eras and video recorders that used to be separate, but are now on the same smart phone. As a result, plant managers are using these PLC-pluses to check energy consumption, reduce waste and find other new things to control.”

Benson Hougland, vice president of marketing and prod-uct development at Opto 22, reports that, while PLCs are usually programmed in Ladder Logic and operate by scan-ning I/O and sequentially solving their logic, PACs employ 32- or 64-bit processors and can use multithreaded execu-tion to carry out several programs asynchronously.

“The power really comes out in the software,” Hougland says. “PLC software is limited at the point its hardware no lon-ger supports it, but PACs can take advantage of more capabil-ities, such as multithreading functions for logic, motion, PID tuning, drives, process control and discrete control.”

Hougland adds that PACs aren’t always better than PLCs because a PLC is still more suitable and less costly for fast, discrete machines that don’t need to share data via Ethernet, while a PAC is better at controlling a platform, running so-phisticated applications and transmitting data, but is gener-ally more expensive. “We also see the line blurring between PACs and PLCs, and there’s also less price disparity between them,” he says. “But if you want to link to a drive, operate a servo system and run an HMI or a bar-code scanner, then you can connect to all of them with a PAC. It can act like a traffic cop, but it’s the software that allows them to come together.”

Paul Whitney, commercial program manager for Integrated Architecture at Rockwell Automation, stresses that many appli-cations still need the speed and simplicity of a dedicated oper-ating system for reliable control. “Some machine builders that need to streamline their modular machine designs for mainte-nance and troubleshooting struggle with complex, PC-based controls and code, so they switch to our dedicated, scaled-down PAC,” Whitney says. “It can handle two, eight or 16 axes of motion and 100 I/O, which means a small machine can get the same performance as a larger, more complex machine.”

Brett Burger, senior marketing manager for embedded systems at National Instruments, adds that, “When users in the past faced complex relay problems, PLCs came along and simplified them. Now users face even more complex problems, so PACs are blending PLC and PC capabilities to solve them too. The next step is to use PACs for advanced control, synchronization and communications, and our re-sponse was to add field-programmable gate arrays (FPGAs) to our CompactRIO PACs, which gives them the openness, power and web access of a PC and the ruggedness of a PLC. This past August, we released our latest PAC, which runs a Linux real-time operating system (RTOS) and lets users save on development time by leveraging open-source code.”

https://www.phoenixcontact-software.com/en/contact/your-contacts/worldwide/usa

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Go Small, Get Flexible; When Bigger Isn’t Always Better For Machine BuildersEmag migrates from large, custom-built equipment to smaller, more flexible, standard-concept

machining centers

By Jim Montague

B igger isn’t always better, more features aren’t always helpful, and many bells and whistles are just noise. All the capabilities a useful machine requires are no more

than what each end user needs to produce its products with the greatest speed, accuracy, efficiency, safety and quality. And this directive is even truer for the many small users with shallow pockets who are just beginning to approach using automated machines and production for the first time.

These are the customers that Emag (www.emag.com) has been reinventing several of its machines to reach. Lo-cated in Salish, Germany, and Farmington Hills, Michigan, Emag traditionally builds big, vertical turning, milling and drilling machines with customized control and operations for manufacturing precision metal parts, mainly for the au-tomotive industry. However, to expand into new markets, Emag also began developing smaller, more flexible versions of its larger machines to serve more Tier 1 and 2 parts suppli-ers and many mom-and-pop machine shops too.

“We wanted to get into new market segments with new customers, and so we developed a new modular, standard-ized concept and introduced it in Europe three years ago and in North America two years ago,” says Marius Mazur, Emag’s product line manager. “Our traditional machines are two or three times larger than our new modular machines.”

How did Emag pack the capabilities of its older, big machines into its new, small ones? Very carefully, espe-cially when integrating its PLC, numerical control (NC), G-code and other essential components into its new half- or one-third-sized footprints. Amazingly, the new, smaller machines still retain the capability of the older and larger

Technology in Action

CONCENTRATED CAPABILITY

The VLC 200 H gear-hobbing machine is one of a series of

machining centers that Emag has shrunk to one-half to one-

third the size of its traditional vertical machines, but which

retains the PLCs, numerical controls, G-code and capabilities of

the company’s larger devices.

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cousins, employing Siemens’ 840 DSL hybrid PLC and NC controller or Fanuc’s 32i and 33i CNC controllers.

“Our new modular machines are the same as our larger ones,” says Mazur. “We just put all our knowledge into smaller spaces.”

Founded in 1867 in Bautzen, Saxony, as an iron foundry and engineering works, Emag was reestablished in 1952 in Es-slingen, Baden-Württemberg, where it manufactured lathes and special-purpose machines. In 1969, it moved to Salish, where it introduced program-controlled, automatic turning machines, which it began distributing worldwide in 1977, in-cluding opening its Michigan-based subsidiary in 1980.

One especially important milestone arrived in 1992, when Emag introduced its VSC, which it reports was the world’s first vertical turning center with pickup spindle. Over time, the VSCs developed into multifunctional, multitasking pro-

duction centers. For instance, about 10 years ago, Emag also got into machining threaded parts for oil and gas piping ap-plications and developed its VL 3, VL 5 and VL 7 vertical centers. Designed to handle the unique material character-istics and requirements of process industry components, the VL series are typically managed by Fanuc’s 32i controller and can be monitored and diagnosed via Emag’s Internet protocol (IP)-based, Ethernet network.

Emag’s equipment covers the entire spectrum of machin-ing processes in metalworking. In fact, besides Emag’s turn-ing, milling and drilling machines, the larger Emag Group’s companies manufacture chucked, shaft-type and cubic com-ponents. Founded, organized or acquired mostly since 2000, these divisions include Karstens, which makes external, cy-lindrical grinding equipment; Naxos-Union, which special-izes in crankshaft grinding; Emag Automation, which pro-vides automation for all applications; Reinecker for internal, precision grinding; Kopp for camshaft grinding; Koepfer for gear hobbing; Emag Laser Tec for assembly and laser weld-ing; and Emag ECM for electrochemical machining.

While its recent modular program started with just one scaled-down machine three years ago, Emag reports its new vertical line includes VL 2, which produces parts up to 100-mm diameter; VL 4, which makes parts up to 200-mm di-ameter; VL 6, which makes parts up to 600-mm diameter; and VL 8, which makes parts up to 800-mm diameter.

“VL 2 makes small, round gear and chuck parts, while our VT 2 and VT 4 have two spindles, so they’re really two machines in one,” adds Mazur. “We also typically add our automated part conveyors to the outside of our machines. They’re controlled by small Fanuc servo motors and can be on both sides of a machine to move work pieces in and move completed parts out.”

To maintain these controls for its users, Emag operates its Service Plus program, which remotely monitors clients’ machines via a password-protected network. “Our users can put their machines on our Emag network, and we can see everything,” says Mazur. “Our PLC guys can view the per-formance of machines on their individual Web pages via our Ethernet-based network.”

Technology in Action

PARTS FOR PROCESS

Emag’s VL 5i vertical machining center is designed

to manufacture parts taking into account the unique

characteristics and requirements of oil and gas piping

applications.

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Before Ripping Out That Old Automation System, Try Getting It Back in Shape FirstIn almost all cases, a retrofit will require less downtime than a rip and replace because the scope

of work is greatly reduced

By Dan Hebert

I f you work for a machine or robot builder OEM, or if you’re a manufacturer with machines and/or robots in your facil-ity, then the subject of automation system obsolescence will

arise sooner or later. When it does, you have three options. One is to rip and replace the entire existing automation

system with a new one, an option covered in detail in our June 2013 Control Design cover story “Old Machine, New Life” (www.controldesign.com/articles/2013/montague-old-machine-new-life/) and touched on in this article. This is the highest-cost option with the most downtime, but the re-sult is a new system that can run for many years.

The second option is to keep the old automation system up and running for as long as possible through a combina-tion of wit, grit and spit. This is the lowest-cost option, but can’t be sustained forever, as sooner or later it will become necessary to either rip and replace or retrofit.

The third option is to retrofit part of the automation system with new components, while keeping other parts in place.

Retrofit AdvantagesIn almost all cases, a retrofit will require less downtime than a rip and replace because the scope of work is greatly reduced. It’s also better than a simple “keep running” solution because it replaces the parts of the automation system that cause the most problems.

In many cases, the base machine is fine, but the control sys-tem needs upgrading. Georg Transformer (www.georg.com) in Germany had that problem with a 1981 lamination shear that it builds for transformer manufacturers. The machine had an ancient 486 PC for the controller. Georg found an upgrade path that let the original I/O work with a new controller in an almost plug-and-play project. (See the sidebar, “Save the Old I/O,” for more on this retrofit.)

Another reason to retrofit arises when support has dis-appeared for the original control system. Michael Lindley, vice president at Concept Systems (www.conceptsystem-sinc.com), a system integrator in Albany, Oregon, first got involved with an aerospace company 12 years ago, when the company that installed and supported a rivet inspection con-trol system went out of business. “We first duplicated the controls, supported them through the life of the system, then re-programmed the machine with all new hardware, but with the identical look and feel,” Lindley explains.

The inspection system checks each rivet just before it’s

Technology in Action

NEW PLC, BETTER BREW Figure 1: Brains Brewery in the U.K. replaced two 27-year-

old PLCs with a new PLC, retaining the original I/O and field

wiring and linking the controller and the I/O with a gateway.

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inserted into the wing skin and crushed to make sure it’s the right rivet, is not upside down and is oriented precisely vertically. It communicates directly with the CNC system, and uses a pair of orthogonal cameras (cameras oriented so that one sees a front view and the other a side view) with custom backlights.

“We installed the first system with Visual Basic 6 and Windows XP,” Lindley says. “The new system uses Visual Studio 2012 and Windows 7/64. We increased the resolution with the third-generation system, although the accuracy of the previous system was adequate.”

Upgrading because of Windows operating system prob-

Technology in Action

The Automate Co. (www.automateco.com) in Pacific,

Missouri, is a system integrator that’s been building

machine control systems since 1997. Barrett Davis, principal

at Automate, says “I am aware of no one that’s still

manufactures, sells and supports I/O hardware that was

being built in the early ’80s. We have multiple customers

for which I provided upgrades to existing machine control

systems without having to replace the original I/O or

field wiring.” he says. His company is currently upgrading

a lamination shear at Georg Transformer that cuts

laminations to size and shape.

The transformer division of Georg (www.georg.

com) makes fabricating equipment used by transformer

manufacturers all over the world. “We’re updating from

a 486 industrial PC controller driven by C++ and assembly

language programming to an Opto 22 PAC controller.

We’re simply switching out all six existing parallel I/O

rack cards with 32 channels of digital I/O brain cards and

connecting Ethernet directly to the original rack.”

In addition to the new migration hardware, Opto 22

provided the command set and serial ports that let the

new controller talk directly to the old equipment.

“One could say that the retrofit migration hardware

cost is pretty close to brand new I/O hardware from Opto

22,” Davis notes. “However, no shutdown is needed. Plug-

and-play switchover to the new cards makes it possible to

design the new program on weekends while the machine is

down, eliminating the need to shut down for an extended

period of a week or more.”

Davis notes that retrofit is used in many cases because

it decreases downtime. “Many manufacturers simply do

not have spare production lines, so rip-and-replace could

shut their operations down if a machine is taken out

of production for more than a few days,” he explains.

“Although this seems an insane approach, it is in fact

very common.”

Other advantages of retrofit migration include no need

to rebuild the entire control panel or reverse engineer

the existing wiring and take the chance of shutting the

machine down for extended periods. “We leave the

wiring in place and just reprogram. The new controller can

be configured and programmed just as if I were installing

the new PAC brains and racks,” says Davis.

Web

Before G4 I/O

After

mistic controller

HMI and programming

HMI and programming

groovfor

mobile

groov server

PAC controller

Data storage

Data storage

groov

groov

SAVE THE OLD I/O

In some automation retrofit applications, the original I/O is

retained, and the controller is upgraded and will work with

I/O that’s up to 35 years old.

SAVE THE OLD I/O

Opt

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Technology in Action

The eFlow nebulizer, developed by Pari Pharma (www.pari.

com) in Gräfelfing, Germany, has been used to treat cystic

fibrosis patients for many years. The company is currently

installing software to optimize automation of its production

equipment, particularly through connectivity improvements.

The company is installing Beckhoff Automation’s (www.

beckhoffautomation.com) TwinCAT software on an existing

PC, and linking this software to an existing Siemens (www.

siemens.com) S7-PLC. “Before the changeover, our technical

infrastructure was somewhat inefficient,” says Ronald

Schmidt, project manager at Pari Pharma. “A very complex

mix of control programs for the Siemens S7 PLC, as well

as PC-based programs written in C++ and using National

Instruments (www.ni.com) LabVIEW made maintenance

without specialized programming knowledge nearly

impossible. In the event of a fault, we had to call in external

specialists on a regular basis.”

The existing automation couldn’t communicate with

Oracle and SAP databases. Traceable parts management

was needed for the complex production process, where

two separate machining operations are executed in one

manufacturing cell.

After the first production step, the part is removed,

processed further and returned for another machining

operation. The parts must be scanned and identified before

each step. And the aerosol generator of the eFlow system

passes through 12 production and testing stations.

“The data from the PLC had to be entered manually in

the databases for further processing,” laments Schmidt, and

replacing the PLC was not an option.

“For years we looked for a machine control system that

was able to communicate directly with the databases,”

Schmidt says. “We chose the TwinCAT Database Server in

conjunction with a Profibus master terminal for the EtherCAT

Terminal system from Beckhoff. However, we didn’t want

to and couldn’t replace the old S7-PLC immediately during

continuous operation. We were looking for an option to

communicate with it via the Beckhoff system without the

need for proprietary hardware.”

The solution was provided by esqmate, GmbH, a system

integration firm in Unterföhring, Germany. The company

has an MPI software library for TwinCAT that ensures that

the Beckhoff software can communicate directly with the

Siemens PLC via a Beckhoff Profibus master terminal using

the MPI protocol. No additional hardware, such as MPI/

Ethernet gateways, was required.

The SAP system receives test data from the Oracle

database, which is connected to the Beckhoff system. SAP

then generates item lists, work schedules and approval

reports, and manages inventory based on this data.

”Because direct communication is now possible

between the existing S7-PLC, the Beckhoff platform, the

Oracle database and our SAP system, we are at last able

to link the control world with business management

solutions,” Schmidt says.

UPGRADING CONNECTIVITY

Bec

khof

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utom

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n

SHOW US YOUR ID

Production of the aerosol generator for eFlow inhalation

device takes 12 production and test facilities. Each part

is scanned and unambiguously identified using an Oracle

database,a new control platform and an existing PLC.

40

lems is a major reason for retrofits. Support for Windows XP ended in April 2014, affecting thousands of PC installations.

One force driving the switch to Windows 7 is the old age of the PCs that run Windows 2000, Windows XP and older operating systems. We often hear that when the old PC dies and must be replaced, users with control and HMI systems that are working OK are forced to make major changes. This raises another problem, Tom Edwards, Opto 22 engineer, observes: “The mandatory shift to Windows 7 and Windows 8 on all of the available newer PCs makes a change in con-trol and HMI software a necessity, as very few of the funda-mental I/O functions remain the same or are upgradeable to Windows 7 or Windows 8.”

Picking on PLCsBrains Brewery (www.brainscraftbrewery.com) in Cardiff, Wales, was developing an increasing variety of beers, so it wanted to upgrade its yeast-handling control system to ac-commodate the new mixes. “The main aim of the project was to upgrade two Allen-Bradley PLC 2 controllers, which were 27 years old,” says Mike Cooper of IAC Engineering (www.iaceng.com), a system integrator in Cross Hands, U.K. “Limited downtime was available—only three days—so the six old 1771 remote I/O racks were retained, but the obsolete controllers were replaced by a CompactLogix PLC.”

The connection between the 1771 I/O racks and the CompactLogix (Figure 1) was accomplished with a remote I/O-to-Ethernet migration gateway from ProSoft Technol-ogy (www.prosoft-technology.com). “Without the gateway, a more expensive system would have been required. This solution reduced the project cost by 40%,” Cooper notes. “Commissioning time was reduced because the remote I/O cards and wiring could be retained. Only the processor and software needed to be added and commissioned, not the field wiring.” and wiring could be retained. Only the pro-cessor and software needed to be added and commissioned, not the field wiring.”

Finding a vendor that’s developed a nice piece of hard-ware or software designed for retrofits can solve a lot of prob-lems. At PARI Pharma (www.paripharma.com), a medical

device manufacturer in Germany, a control system retrofit project connected a Siemens S7 PLC to modern databases. (See the sidebar, “Upgrading Connectivity,”)

Keep ‘Em RunningBut when times are tight and the existing machine or robot is near the end of its useful life, keeping the automation sys-tem running by hook or crook can be the way to go.

Some companies put off upgrades until they absolutely have to do them. David Perkon, vice president at AeroSpec (www.aerospecinc.com), a machine builder in Chandler, Ar-izona, has customers that prowl eBay and the Internet for old parts, employ maintenance people to keep the machines working, and put off upgrading as long as they can. “Keep-ing legacy equipment running without replacing the hard-ware or software is a nice dream until something fails, and you’ve used your last spare,” he says.

One of his customers kept an old machine running for years, until it started having quality and production problems. An analysis revealed that the machine was fine, but the control sys-tem needed an upgrade. (See the sidebar, “Time to Upgrade,”)

Because old PLCs are so reliable, it’s often difficult to justify a retrofit. Intelligrated (www.intelligrated.com), an OEM of material handling systems in Mason, Ohio, supports its older systems, such as Alvey palletizers. “We actively support several customers who have the original PLC 2 1772 series processor,” says Chris Hutson, Intel-ligrated’s manager of product support engineering. “Al-though these machines were manufactured beginning in the mid-1980s, we continue to modify their PLC logic to incorporate new product patterns. Also, we provide trou-bleshooting for these processors, which have been discon-tinued by the manufacturer.”

Some of their other machines over 30 years old have Modicon PLCs programmed with DOS-based PCs and manual switch panels instead of modern, touchscreen technology. “In many cases, this requires us to read 5¼-in. floppy drives to obtain old machine program files and in-formation from original drawings.”

Machine builders appear to be better at keeping legacy

Technology in Action

41

Technology in Action

AeroSpec (www.aerospecinc.com) in Chandler, Arizona,

designs and builds a variety of custom automated

equipment for the medical, semiconductor, automotive

and defense industries. David Perkon, vice president, says

he’s seen many problems with legacy control systems.

“It’s not uncommon to have firmware and software

driver issues with legacy hardware and software,” he says.

“Working with a dated operating system or updating

the operating system can cause issues with I/O drivers,

application software and PC-based operator interfaces.

A programmable controller’s firmware might not be

compatible with rack-mounted motion control cards and

other smart modules.”

Roadblocks to upgrading are many, he says. “There

are the ‘It costs too much money,’ or ‘I can’t afford

the downtime’ customers. With many customers, not

updating legacy hardware and software is more of

a culture than a time-and-money issue. It’s the ‘It’s

running fine, don’t mess with it’ attitude. All that sounds

reasonable until the reality of failures brings production

to a halt. Many customers just don’t want to spend the

money or are afraid to upgrade until they absolutely

have to.”

AeroSpec is happy to retrofit new controls hardware

to existing equipment. “We recently updated the

automation system for a large medical-device

manufacturer. The equipment ran slow and had

significant quality and productivity issues. It was a

machine the customer had been fixing for years.”

Significant machine downtime was occurring because

of product breakage, machine jams and alignment issues.

A team of three maintenance technicians were required

to support the 10 machines every shift. Although the

technicians kept the equipment running, the root cause

of the problems—the controls hardware—was never

addressed.

AeroSpec performed a detailed equipment study and

found the legacy control system and software were

limiting production. The machine controller and motion

control hardware were upgraded.

“Replacing the motion controller with a Rockwell

Automation (www.rockwellautomation.com)

CompactLogix controller and Kinetix multi-axis

servodrives greatly improved machine performance,”

Perkon reports. “The new hardware fit nicely in the

existing control enclosure, and a new PanelView HMI

enabled the addition of machine status, fault display,

manual functions and setpoint adjustment screens.”

The upgraded hardware allowed programming of a

new machine sequence with a creative motion profile.

“In the end, we tripled the speed of the equipment and

significantly reduced scrap,” Perkon beams. “The control

hardware and software upgrade also helped highlight

other areas where the equipment could be optimized.

It’s simple math. The new hardware and software quickly

paid for themselves.”

TIME TO UPGRADE

IN THE RIGHT SPOT

AeroSpec designed and built this and other stations

on a high-speed, thin-film-solar assembly line. This

station singulates, orients and tests diodes before they’re

adaptively placed and welded on the thin-film product by

dual-vision guided robots.

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systems running than some vendors of control systems. The Bradbury Group (www.bradburygroup.com), a builder of metal-processing equpment (Figure 2) in Moundridge, Kansas, for example, keeps its customers’ legacy equip-ment running by carrying backups of all the programs that operate the equipment they manufacture.

“Issues often arise when we have to support third-party equipment,” says Dennis Clark, Bradbury’s project software en-gineer. “Sometimes it’s the proprietary software they provide; other times the equipment vendor might go out of business.”

Bradbury builds coil processing and roll forming ma-chines, designed for a life of 20 to 30 years. “The manufac-turing lifecycle of the average electrical component is seven to 12 years,” Clark notes, “but for PC-based products such as HMIs, it can be as short as three to five years.”

Some vendors do their best to support older automation sys-tems. “While no one can completely eliminate the risk associ-ated with legacy operating systems, some manufacturers have tools and services to maximize the life of legacy equipment and minimize risk,” explains Lonnie Morris, senior manager at Rockwell Automation (www.rockwellautomation.com). “Lifecy-cle extension services from companies like Rockwell Automation provide service options to fit each company’s individual needs.”

Rip and Replace Has Its Place Although retrofit or keep running have advantages in many scenarios, that’s not always the case, as sometimes it’s just better rip and replace.

“We encourage our customers to migrate from obsolete systems to current, actively supported software and hard-ware platforms,” Intelligrated’s Hutson notes. “For a soft drink company and other beverage facilities, we converted our high-speed 920 series palletizers from obsolete PLC pro-cessors to modern automation based on the ControlLogix platform. On several projects, we lowered the customer’s to-tal cost of ownership, met operational compliance regula-tions, and increased flexibility and performance.”

Much of the time, the actual machine itself is reliable, but the control system is causing problems. For example, one of Delta Computer Systems’ (www.deltamotion.com) customers that manufactures automotive components ran

into a problem with servo-controlled lathes in its facility. “The lathes were well-designed precision machines, but

the servo control system was the original analog design ap-proaching 22 years of age,” explains Bill Savela, marketing manager at Delta. “While the machine still produced ex-cellent parts, the downtime associated with the servo-con-trol system was becoming an issue. We determined that the primary problem was the lack of reliability of the old analog control system, and they decided to replace it with a Delta servo motion controller.”

And sometimes a retrofit or upgrade isn’t enough. “Whether it’s old software talking to new devices or new software talking to old devices, a pop-up message warn-ing of a compatibility issue is common,” notes AeroSpec’s Perkon. When these and other types of compatibility issues arise between old and new systems, sometimes the entire control system has to be replaced.

Technology in Action

ALL COILED UP Figure 2: This Bradbury coil processing line uncoils, levels,

cuts to length and automatically stacks orders. The machines

are designed for a life of 20 to 30 years. The company

keeps its customers’ legacy equipment running by carrying

backups of all the programs that operate the equipment

they manufacture.

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Software at the Core of AB ControlsAB Controls uses its software expertise to develop automation and robotic solutions

By Jim Montague

Many people and organizations become what their times demand, and machine builders are no excep-tion. So when biotechnologies and biopharmaceu-

ticals began to boom in the 1990s, they needed machines and equipment to run increasing numbers of experi-ments. That’s a lot of test tubes and sample wells to fill.

One of the machine builders that showed up to help was AB Controls (www.abcontrols.com) of Irvine, Calif., which provides automation, robotics and other services to customers in the pharmaceutical, R&D, medical de-vice, aerospace and other fields. Its two primary types of automation include multi-axis robot integrations, mainly used in laboratory automation, and functional automated testing equipment. Established in 1997, AB Controls began assisting biotech clients that typically required high-throughput screening or needed to run and secure results for numerous parallel tests.

“Our users need to run thousands of experiments to find the most effective solution or treatment, but that many experiments can only be done with robots,” says Mike Nariman, AB Controls’ president and founder. “For example, our control system and software allowed Carl Creative systems to design instruments that employed multiple heads—some machines had up to six dispense heads—for ever-increasing levels of parallel processing to interact with 96- and 384-well plates. This increased throughput tremendously.”

Consequently, AB Controls also came up with a soft-ware-based solution for performing multiple operations or running several robotic stations at the same time, such as controlling Carl Creative’s four-axis gantry robot and four dispensing heads, running interface software and operat-

ing its scripting tool. Nariman reports that, before 2001, AB Controls was only involved in writing software and architecting control systems. After 2001, it got involved with building robotic and automated platforms as well.

“We’re different than a machine builder that out-sources its software and may add a hodgepodge of it to

Technology in Action

ARMED TO ANALYZE

AB Controls’ Tix is a robotic titration work cell that performs

automated, precision walk-away testing of up to 105 samples.

It performs Karl Fischer titration using a Mettler-Toledo titrator

and balance, two pumps and a five-axis robot arm.

AB

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their equipment,” Nariman explains. “Our emphasis is on systems and integration, so we develop our own source code. We’ve built software platforms that have evolved over time, and new functionalities are added every day. All our machines start from a 3D model, and we keep track of all versions of mechanical as well as electrical and software designs and code. The flexibility in our software tools lets us connect better with end users because their engineers know we’ll be able to come up with the right custom ma-chine or solution for them. We’re not a machine shop. We use trusted partners for those services. Instead, we try to keep tight control over design and make sure all parts are made with utmost care and precision. All machined parts and off-the-shelf items are assembled and wired in our fa-cility, and tested thoroughly prior to customer buy off and validation. This allows us to focus on the most important aspect of our work which is design.”

AB Controls concentrates on multiple programming environments and languages, including National Instru-ments’ LabVIEW, Microsoft .NET for visual basic (VB) and C#, and traditional ladder logic. It also handles spe-cialty languages and environments for motion control and vision devices to help create unique and seamlessly inte-grated mechanical and electronic solutions. The compa-ny’s custom automation and robotic systems also employ its proprietary Focus software.

“Our philosophy is that simple is better, but software is really king and is at the center of all we do, Nariman says. “A good automation solution always benefits from good software. We also don’t believe in one size fits all. While we try to keep similarity between systems, we do not box ourselves into just one type of controls for all solutions. Mostly, we use Mitsubishi PLCs, Animatics smart motors from Moog with integrated controls/drives, and vision sys-tems and vision-guided multi-axis robots. Sometimes sev-eral control systems are integrated into one solution.”

Nariman reports that one of AB Controls’ more-re-

cent breakthroughs came in 2005 when it integrated a six-axis Mitsubishi robot into a titration station to assist a lyophilization process—a type of freeze drying for phar-maceuticals. “One of their engineers called and said they had an old robot with archaic controls that was prone to breakdowns, and they wanted a new robotic system that they could load up, walk away from and come back the next day to get finished products and analysis,” Nariman says. “The old machine wasn’t very reliable because it used a potentiometer for feedback of motion axes, which made it prone to abrupt changes. We integrated a six-axis robot with absolute encoders and integrated the analyti-cal instruments into one solution using our Focus soft-ware. In the end, we developed a robotic machine that took up one-fourth of the old machine’s floor space and was 10 times more reliable and a lot less costly.”

Nariman adds AB Controls’ innovations in integrating analytical instruments and robots into one machine with uniform software are what enable its machines to be bet-ter coordinated and easier to maintain. For instance, one of its latest systems is the Tix robotic titration work cell that performs automated, precision, walk-away testing of up to 105 samples. It performs Karl Fischer titration using a Mettler-Toledo titrator and balance, two pumps and a five-axis, articulated robot arm.

AB Controls also has used its robotic and automation skills to develop functional testing systems for evaluating implant components, and it’s getting into compound-man-agement systems. Similar to high-throughput screening, compound management involves upstream processes that chemists use to make sure precise amounts of substances are dissolved in precise amounts of solutions, so their ex-periments and formulations will be accurate.

“Software is what allows us to transfer our robot-ics and automation skills,” Nariman says. “If a func-tion needs to happen, it may be occurring in different disciplines, but it’s still the software that drives it.”

Technology in Action

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Technology in Action

OEM Builds Flexible Machines for Demanding CustomersEhrhardt combines user input, experience and quality to create flexible machines for manufac-

turing appliances, HVAC units and other products

By Jim Montague

Variety might be the spice of life, but delivering it can be a head-ache. So if you need flexible ma-

chines that can make all kinds of new products and parts, it’s vital to have an experienced builder that can provide all the innovations and quality you need.

“Our first job is to get our customers involved up-front and keep them in-volved in the design process, so we’ll build a machine that does precisely what it’s intended to do,” says John Deibert, special machines business seg-ment manager at Ehrhardt Tool & Ma-chine (www.ehrhardttool.com) in Gran-ite City, Ill., just outside St. Louis. “This process is more important now because markets are demanding changes in the design, look and capabilities of many appliances, HVAC units and furnaces. So instead of building a machine that produces one parts family for a furnace cabinet, our users need machines that can make more sizes and types of parts.”

Ehrhardt designs, builds, assem-bles and tests tool and die, automated equipment and customized machines, mainly for users who need to punch, bend, form, weld and braze sheet metal. Most of its equipment is used to man-ufacture commercial and residential HVAC condenser units, heat exchang-ers, furnace cabinets and consumer appliances, such as washers, dryers, ov-ens, stoves and cooktops. It also builds leak-testing vessels and heat-exchange cells for forced-air residential furnaces.

Started by Willis Ehrhardt in 1937, the company op-erated during World War II and for decades after as a classic tool and die shop. In the early 1990s, Ehrhardt be-gan adding automation and controls to its machines and sought to bridge its mechan-ical and electronic systems. “We wanted to be a one-stop shop for automation, controls and interfaces,” Deibert says. “So as part of the engineering group, I did the mechanics, Dave did the controls, and our philoso-phy was to combine them by taking an approach from the top on down. For-tunately, we had talented people and a team that could provide what custom-ers needed, and we’ve been doing it for 20 years.”

Deibert reports that Ehrhardt’s ma-chines and production lines use PLCs, PACs and HMIs from Rockwell Auto-mation, Mitsubishi, Omron, Schneider Electric and GE Intelligent Platforms. These components and its machines are typically networked with EtherNet/IP. For its load and testing equipment, Ehrhardt uses PC-based controls and LabVIEW software from National Instruments.

“EtherNet/IP is simple and easy for our users to understand, and it’s in-expensive,” Deibert adds. “We’re also doing remote diagnostics on critical equipment. Customers grant us ac-

cess to their VPNs to monitor and ad-just machines, but we’re also looking at some Internet-based solutions.”

Besides involving customers, Dave King, Ehrhardt’s senior controls engi-neer, adds that Ehrhardt’s other driv-ing force is quality and delivering a low cost of ownership to its users. “Peo-ple might spend a bit more up-front, but they’ll spend a lot less on a quality machine in the long run,” King says. “Now our machines can handle more patterns and make it easier for opera-tors to enter data because our controls use more tag-based, portable software. This means operators can adjust reci-pes via on-screen fields for different pa-rameters, which is simpler than typing in code. This is a lot like having reus-able function blocks or a software li-brary, which is more flexible than hav-ing to input a one-off ladder program for each machine.”

OFF THE STACKA vertical pallet destacker is the first of five machines

in Ehrhardt Tool & Machine’s Furnace Cabinet line,

which its customers use to build enclosures for

residential and commercial furnaces.