Open Systems Mean Freedom of Choice in Manufacturing

Formal and de facto standards enable control engineers to construct a system from components of different vendors, extend and modify it as requirements change, and avoid being at the mercy of a single vendor.It has been over 10 years since employees of Opto 22 (Temecula, Calif.) wore black armbands to commemorate the demise of proprietary PLC control in manufacturing at the hands of Open ...

09/01/1999


KEY WORDS

 

  • Machine control

  • Systems Integrators

  • Open systems

  • PC-based control

  • Software for control

Sidebars:
Check these Before Implementing Open Systems
Systems integrators view: Are open systems too easy?
Benefits outweigh drawbacks

Formal and de facto standards enable control engineers to construct a system from components of different vendors, extend and modify it as requirements change, and avoid being at the mercy of a single vendor.

It has been over 10 years since employees of Opto 22 (Temecula, Calif.) wore black armbands to commemorate the demise of proprietary PLC control in manufacturing at the hands of Open Control. While PLCs are still used, the open control concept has spread even to 'proprietary' control suppliers.

Along the way, the term 'open' has been used to excess leaving many engineers wondering whether there is any value in open systems or if it is just so much marketing hype. They can be assured that there is much value in adopting open systems for many, if not most, manufacturing processes. (See other Cover Story in this issue, with process emphasis.)

Real applications fulfil the promise of open systems. A user selects a controller that meets criteria of programming, support, and pricing. After settling upon one of the competing I/O buses, I/O modules from several of many competitors are specified. Should support be lacking for a component or prices dramatically rise, then the user can choose another vendor with a product that easily fits into the system.

User demands and technology advancements fueled evolution of automation controls. See pie charts provided by (Think & Do Software, Ann Arbor, Mich.). The common view reflects three to five segments here shown as PLC, CNC, DCS, and Custom. Segment delineation is quite clear; each segment has its set of leaders. Three layers of control (second chart) have developed: software, controller (moving to PCs), and I/O devices. Lines among the various controller types have blurred. The movement to PCs has the effect of decoupling I/O modules from the hardware platform. Thus many new players have emerged in that business and in companies specializing in integrating multi-vendor components. For the next decade or so, the landscape for controllers will see a new category-open controller-taking its place in the market. The relative slices of pie will probably begin to show open controllers gaining share while older technologies remain.



This series of graphs shows automated controls market
evolution, from present segments of only PLC, DCS, CNC,
and custom controls to the addition of open control and the
eventual blurring of lines between control types. Each
control type actually consists of software, controller (moving
toward PCs), and I/O devices with software effectively
decoupling controller from I/O device.

Standards drive openness

One consistent theme in almost everyone's definition of open is the concept of interoperability. This means that a component from one vendor can replace a similar component from another without complication or loss of production. To accomplish this takes the development of and adherence to industry standards. These standards may be either formal-that is, approved by a governing body such as IEC or IEEE-or de facto through market forces. De facto standards are protocols so widely used that almost everyone is familiar with them.

Think of all the standards for industrial automation today. There are fieldbus standards like Profibus, DeviceNet, Interbus, Seriplex, and Ethernet. IEC 61131-3 standardizes programmable controller programming languages-also widely used for PC-based control. OLE for Process Control (OPC) defines a standard method for communicating data across hardware and software platforms. Microsoft Windows NT and its components like ActiveX, COM, and DCOM are so widely found among automation products and users to be often cited as a de facto standard in the industry.

Automation users also have an organization to look after their interests promoting standards for interoperability. The OMAC Users Group has members from organizations as diverse as GM Powertrain, Procter & Gamble, Boeing Aircraft, and Cummins Engines. A voluntary organization without paid office staff, OMAC can be found at its web site hosted by ARC Advisory Group (Dedham, Mass.) at www.arcweb.com/omac/ .

OMAC-formed just five years ago as a joint effort of Chrysler, Ford, and General Motors-defines common API's (application program interfaces) for interoperable Open Modular Architecture Controllers in automotive manufacturing. The group has several working groups. One has developed a program to help give business justification to the adoption of open systems. Another had significant input to Microsoft's development of version 3.0 of Windows CE, the real-time operating system for control.

Free standards

Is there a common definition for 'open?' Refreshingly, most automation suppliers seem to have congruent definitions with some different emphases. This bodes well for standards development and the success of interoperable components within an automation system.

Karl Meihofer, product manager for Transparent Factory and I/O at Schneider Electric's Automation Business (North Andover, Mass.), defines open as 'standards and technologies openly documented, available freely with no licensing or royalty fees, and popularly subscribed to by many vendors. While the term can be applied to hardware and software, it is open communications that will ultimately drive open systems in industrial automation. Ethernet and TCP/IP are shown to be safe, secure, and reliable through extensive use by the Internet. New technologies like fast switches can make it deterministic. An unresolved area lies in the application layer.'

Nic Gihl, senior vice president of GE Fanuc Automation (Charlottesville, Va.), says, 'Open is a combination of data connectivity and hardware and software portability. Ethernet and OPC are examples of connectivity, while portability is seen in hardware and software support across multiple platforms, for example, across the breadth of GE Fanuc's controller products and reaching out into third party products.'

One result of the emerging philosophy of openness has been the blending of various controller types. CNCs, once a stand-alone island of control, now are increasingly an integrated part of a manufacturing line. Jeff Kao, manager of GE Fanuc's CNC business, notes 'Open interface for CNCs enhances user productivity and the ability for OEMs to provide tools. Open interface also provides connectivity from CNCs to the rest of the manufacturing enterprise.'

Opto 22 sees customers defining open as ability to combine components from various vendors into a working system along with open access to documents and specifications when components must be changed or customized. Adds Benson Houghland, director of Technical Marketing, 'Often, users seeking an open solution really want a solution allowing for change, modularity, and flexibility.'

'Ability to interact within or among software applications independent of the application' is Kevin Gordon's definition. Mr. Gordon, senior software architect at Rockwell Automation's Rockwell Software unit (Mayfield Heights, O.), characterizes attributes of openness as extensibility, interoperability, portability, scalability, and modularity.

Adds Dave Rohn, development manager of Rockwell Automation's Allen-Bradley SoftLogix Business, 'Open refers to automation control strategies that leverage accepted and tested commercial technologies. This allows multiple products to coexist and integrate on the same platform.' Allen-Bradley-once characterized as the epitome of 'proprietary' systems-is now actively pursuing open systems, an example for some that the open systems trend is here to stay.



A control systems consists of I/O devices (sensors and actuators), control hardware,
control software, human-machine interfaces, and links to business systems. Device fieldbuses
have allowed the decoupling of I/O modules from the controller rack, and Ethernet advances
allow integration of the data accumulated from the field

PCs are open platforms

According to VMIC (Huntsville, Ala.), an open system uses industry-standard hardware and software components. These include open-architecture PC-based platforms like ISA/PCI, CompactPCI, and VME with PC-based software tools. An open system allows users to choose best-in-class products from a variety of companies to implement the optimal automation strategy.

Tom Gross, ceo of Xycom Automation (Saline, Mich.), says, 'The open automation environment offers users the ability to draw upon the sum of all the world's PC-based creativity. For instance, there are many free tools available on the World Wide Web. This pool of resources is growing exponentially, with some studies indicating PC-based research and development figures at 30 times that of traditional automation.'

Wonderware (Irvine, Calif.) notes that open products mean no single vendor controls the technology via licensing agreements. It promotes open and integrated systems. Wonderware's products are open in the sense of adhering to industry standards yet integrated to relieve users of the hassle of doing their own integrating.

Brian Brickhouse, Cutler-Hammer Automation (Westerville, O.) automation product line manager, echoes the freedom of choice users gain. He also notes, 'Open systems provide better information in a usable format, integration with other plant systems, and lower installation, start-up, and operation costs.'

Another indication of merging CNC and automation control technology is the emergence of MDSI's (Ann Arbor, Mich.) open CNC solution. Jim Fall, president and ceo, points out, 'An open system contains no proprietary cards or other hardware while running on an off-the-shelf PC and a single operating system like Microsoft Windows NT. The software includes open APIs for integration of third- party software. Software upgrades will continually improve the application.'

Reduce risk in change

Mark Knebusch, Interbus group director at Phoenix Contact (Harrisburg, Pa.), says that open systems' reliance on standards lowers risk of change when situations warrant. Using standard programming languages reduces training and allows programmers to get up to speed more quickly on new controllers. Since many suppliers will be using products based on the same standards, the larger user's base and increased knowledge base will speed design and decrease troubleshooting time.

National Instruments (Austin, Tex.) has long been a proponent of industry standards, including active participation on OPC-Object Linking and Embedding (OLE) for Process Control. NI sees connectivity standards as the single largest factor defining an open automation system. Industrial network standards like Foundation Fieldbus, Profibus, and DeviceNet allow mix-and-match selection of sensors, transmitters, control valves, and other control devices from multiple suppliers. Standards enable information exchange without developing custom communication solutions.

Commotion Technology (San Francisco, Calif.) touts the open benefits of Java, a programming language designed to operate on a number of computer platforms. Complex automation systems can be designed and implemented integrating vision, motion, and machine control more easily and inexpensively using open control platforms.

Intellution (Norwood, Mass.) cites Microsoft's Windows DNA (Distributed interNet Architecture) as a de facto industry standard promoting software interoperability among applications regardless of the vendor.

Much like the CNC with open front end explained above or combining openness with custom integration, Omron Electronics (Schaumburg, Ill.) believes that hybrid systems-consisting of part open systems, for example software using OPC, and part proprietary PLCs-will be prevalent in manufacturing for some time to come.

For Dave Gee, engineering vice president of Steeplechase Software (Ann Arbor, Mich.) open systems refer to hardware platforms available from many competing vendors capable of running applications also available from many competing companies. The most common industrial automation platform is the combination of PC with Windows NT or CE operating system.

Companies see benefits

U.S. Steel needed to update automation components at its Fairfield Works plant. As automation emphasis has shifted from hardware to software, U.S. Steel decided this would also be a good time to re-evaluate the entire control structure. A major requirement for implementing new drive/generator systems was no down time for switchover. The VME-bus computer system and control software from VMIC were integrated with existing GE Fanuc drives and PLCs. The new system was installed, ran parallel to the existing process to prove it out, and then ran main control without halting production.

Daishowa America (Port Angeles, Wa.) has a pulp mill and wanted to implement a new open control technology replacing an existing DCS. The hydrogen peroxide bleaching process uses Foundation Fieldbus components and control software from National Instruments. Other equipment came from Smar International and Relcom. The project achieved significant cost savings from control hardware, wiring reduction, maintenance, and system checkout. Control hardware, I/O devices, and communications are all contained within field transmitters with no need for air-conditioned racks with raised floors for cabling.

IBM Microelectronics (Burlington, Vt.) implemented a real-time process monitoring system using controllers and I/O modules from Schneider Electric with communications of Modbus RS-232 to Ethernet TCP/IP bridges, and commercial Ethernet routers and bridges. System architecture follows a triple-tier model of device, control, and information layers such that all are capable of independent operation should other layers fail. The system resulted in reduction of Mean-Time-To-Repair, increase in Mean-Time-Between-Failures, reduction of time to detect processing errors, increase in process yield due to minimized product variation, and pinpointing tool problems by the integration of smart sensors with MES and Advanced Process Control [is the last a product? If so whose?].

An implementation showing long-term benefits of open systems comes from Flying J Refinery (North Salt Lake City, Ut). The diesel fuel refinery underwent a major control system upgrade in 1993 using state-of-the-art Intel x486-based PCs, Microsoft Windows for Workgroups, Wonderware software, and hardware from Opto 22. The open solution was originally chosen because of significant up-front cost savings. Over the years, the PCs have been upgraded to Intel Pentium-based machines with an Ethernet backbone and upgraded Wonderware software and the latest I/O devices from Opto 22. The open system allowed later integration of a tank farm gauging system.

Thanks to the tight integration of PCs with Fanuc's Series 160 open architecture CNC, Mori Seiki was able boost machining productivity by 40%. A Microsoft Windows-based graphical interface was important to simplify operation and eased maintenance. During operation, the main monitor displays a graphical reproduction of the pallet pool layout. The pallets change color and are animated to reflect variations in the machine status. Data logs and part descriptions are all stored on the PC's hard drive and machining programs are downloaded automatically based on the pallets loaded. Then, every step of loading, transporting, and machining is monitored to ensure safety and proper operation. Logged data also help verify machining quality and provide real-time measurements of cycle times. Because the system is linked through an Ethernet network, remote monitoring and control are possible from a central site or even off-site...allowing a single operator on the floor to service the entire system.

Decisions moving toward open

Like the awe-inspiring formations of a flock of starlings in the fall-each bird making its own decisions yet part of a magnificent pattern-controls users and suppliers are deciding what are the best control architectures for various automation problems, yielding a pattern of increasing popularity of open systems. Users will no doubt be blending new open systems with current control systems for the next several years. There will be many instances of hybrid products and systems combining the best of both worlds toward the solution of particular automation needs. It will be interesting to see when, or if, Think & Do's projection of market share for open control becomes reality or if things settle into a more equal segmentation.




Check these Before Implementing Open Systems

Define expectations for system performance

Define expected results

Develop clear specifications for controllers, software, and networks

Define critical interfaces and communication requirements

Decide who will do the integration

Solicit input and support from all affected departments

Source: Control Engineering

Systems integrators view: Are open systems too easy?

An informal discussion at last spring's annual conference of the Control System Integrator Association (CSIA, www.controlsys.org) focused on the consequences of open systems technology. It was agreed that open control systems generally require much less custom programming and specialized product knowledge than their proprietary counterparts. That should make integration projects easier, hence more profitable for system integrators. But is it possible for open control systems to become so easy to implement that end-users won't need an integrator's services at all?

Open system vendors don't seem to think so. Greg Wilkinson, business strategy manager of Rockwell Automation's Process Business Unit (Milwaukee, Wis.), states 'Every application is unique, and therefore requires a unique solution. While products are becoming more flexible and easier to install and configure, highly qualified integrators with specific industry experience are a key part of a successful control solution implementation. Rockwell Automation partners with system integrators for that very reason-because of the value-added service they provide.'

Dave Faulkner, executive vice president of marketing at Cimetrix (Salt Lake City, Ut.), agrees. 'I believe that open architecture and Windows NT will not eliminate the integrator channel, but transition integrators from having to know proprietary development systems to focusing on industry standard environments such as NT, VC++, and VB. The result will be that the software methodologies used in the mainstream software business will now be used in the automation business resulting in much more reliable and maintainable applications. It does not mean that users will develop everything themselves and integrators won't be needed.'

Still, not all system integrators will benefit from open systems technology. Jeff Tropsa, business development manager at ObjectAutomation (Santa Ana, Calif.), notes that open systems will eliminate a lot of custom programming, so integrators who rely on programming time to generate billable hours will lose revenue in the near term. On the other hand, open systems technology should allow them to replace the lost work with more projects that they can complete more quickly.

Even if open systems become easy enough for end-users to implement themselves, there are steps that system integrators can take to remain valuable to their clients. Dan Hirsh, marketing director at Intellution (Norwood, Mass.), observes that integrators can use the rapid expansion of open systems technology to their advantage. If they can keep ahead of their clients in technological expertise, they will still be needed to work on projects that their clients can't handle in-house-at least not yet. 'It's part of our job as a vendor to keep integrators ahead of the technology curve through education,' he adds.

Mr. Hirsh goes on to note that integrators can also be important resources for keeping ahead of the hype that has grown up around open system technology. Staying current on what's actually available and what really works can be among the greatest services that integrators can provide their clients, even before a project gets underway.

Benefits outweigh drawbacks

Users and suppliers of automation systems cite these benefits:

Reduced cost of installation,

Ability to upgrade system easily,

Choose 'best-in-class' products,

Reduce dependence upon just one vendor,

Ability to integrate special-purpose products,

Ability to integrate data with entire enterprise,

Leverage commercial technology-reduces cost and training, and

Reduced development costs.

There are drawbacks involved with implementing open systems:

'Finger pointing' among vendors while troubleshooting problems,

User is responsible for integrating the components (or use an integrator-see Vance VanDoren's sidebar),

User must develop system specifications and define outcomes before selecting vendors and products, and

Potential costs of stocking parts from multiple vendors.

Source: Control Engineering



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