One is Wide Open The Other is Open Wide

What does "open control" currently mean for control engineers and their widening sphere of influence? The meaning of open control varies widely, depending on time and application. It can involve standard interconnections among hardware and software and reach across the enterprise and supply chain. It also can refer to preservation and easy scalability of programming across platforms, and includ...

By Mark T. Hoske April 1, 2003
  • Software and information integration

  • Open systems

  • Control architecture

  • Standards and specifications

Blending PC function in PLC form factor protects ‘secret sauce’ Automation architectures aim to insulate, preserve, maximize assets

What does “open control” currently mean for control engineers and their widening sphere of influence?

The meaning of open control varies widely, depending on time and application. It can involve standard interconnections among hardware and software and reach across the enterprise and supply chain. It also can refer to preservation and easy scalability of programming across platforms, and include networking, programming environments, and architectures.

Here’s how “open” can help you … and hopefully make life a lot more like a walk on a prairie than getting a root canal.

Open can mean…

Michel Jabbour, manager for PC-based automation, Siemens Energy & Automation (Norcross, GA), says open can mean use of standard programming languages, such as those covered under IEC 61131-3, and standard communications to the platform such as OPC. Open also means OEMs’ ability to integrate custom C++ code into the control platform, communicate to multiple device-level networks, or even take the PLC kernel as an application program interface (API) and embed it into an operating platform of choice, Mr. Jabbour suggests.

Another dimension to open permits use of commercial information technology instead of proprietary technologies in appropriate system areas, such as networking, workstations, and operating systems, says Bob Hausler, vp Industrial IT Systems marketing, ABB (Rochester, NY). Communications standards, once proprietary by vendor, are now open for all to use, Mr. Hausler, explains, allowing “users to integrate information with minimal fuss and without custom software interfaces, which are expensive to acquire and difficult to maintain.”

Open goes beyond elements of a controller’s operating system, networking protocol, or software architecture, says Paul Ruland, PLC and I/O product manager; AutomationDirect (Cumming, GA). “Open control products can include components within the physical layer of networking, CAT5 cable, or an RJ-45 style Ethernet interface, DB9 and DB25 serial connectors.”

Open also means being able to buy a variety of products from a variety of vendors and have them work seamlessly in an application, according to Mike Miclot, SoftLogix business manager, Rockwell Automation (Milwaukee, WI). That requires a variety of products accessible to all users, and generally more than one source of enabling technology for automation suppliers, he says.

Some technologies remain closed, but can be connected to open technologies, explains Diego Areces, networks team leader, Schneider Electric’s Automation Business (North Andover, MA). He says, “While no PLCs are open today, the tools that can work with them are increasingly open,” such as Modbus TCP/IP, the Internet, and Ethernet. “Customers want open solutions, but there’s a great deal of confusion caused by widely varying interpretations about what is open.” Mr. Areces says, “An open technology is free, and you can easily access information about it without having to pay a company or join an organization.”

Over time, automation control systems have been undergoing a steady change, says Larry Komarek, Phoenix Contact (Harrisburg, PA) automation systems marketing manager. “The goal is that users want to be able to instantly interconnect any automation device and have it controlled by any vendor’s control software without reprogramming. Industrial automation has been moving in this direction.” The IEC 61131 standard allows the same maintenance people to maintain different vendors’ equipment.

Industrial PCs with soft logic or embedded PLC boards provide space and installed cost savings compared to separate components needed for large applications, Mr. Komarek says. Instead of PLC vendor-proprietary “coprocessor” modules, customers use the PC with industry-standard software communicating to the control program via OPC interfaces. This lowers hardware costs and adds ability to purchase and easily integrate “best-in-breed” higher functionality and ease-of-use software, he suggests. Embedding PLC functionality in Microsoft Windows CE-based panels allows a lower cost/smaller scale version of industrial PCs, replacing PLCs, where operator displays are not required, Mr. Komarek says.

Customer expectations

Competitive demands, shorter product cycles, faster launches, and smaller lot sizes all lead to the need for open systems. Other requirements include security, reliability, information exchange with other systems, more accurate and timely information, and better visibility into and control of manufacturing process—all without compromising the control environment, ABB’s Mr. Hausler suggests. Needs include:

Open and proprietary control technologies can work together, as this typical combination from AutomationDirect shows. I/O devices for AutomationDirect’s DL205 micro-modular PLC line are based on a proprietary network technology and use an open standard cabling and interface (via standard RJ-45 Ethernet patch cabling up to 30 m). This is one way proprietary technology can combine with open technologies—Ethernet, DeviceNet, Profibus, and OPC products—for controller-to-controller networking and HMI/data-serving functions.
  • Integration of process information with the ERP system;

  • Plantwide material tracking, where products in progress can be traced from raw material as received in the plant to finished product leaving the plant; and

  • Integration of information from multiple plants that can be viewed from one place, so that different process/production line operational efficiencies can be compared.

Mr. Miclot says Rockwell Automation customers don’t necessarily expect “openness,” but rather the resulting flexibility and freedom of choice.

Clyde Thomas, product line manager, Eaton Corp. Cutler-Hammer (Milwaukee, WI), says, “Many customers, however, see a need to gain competitive advantages through a variety of means, including the use of technology and open-control architectures to enable enterprise integration, emerging technologies and products in incremental fashion and with minimal disruption, and/or to add value which is unique to them—without investing or risking this investment on a single vendor or closed environment, which would limit portability and reuse.”

Mr. Ruland adds that customers “now commonly expect an increased level of open control hardware and software products” and the resulting lower setup and lifecycle costs.

Technologies feed the need

Technologies feed the need for open systems and result in benefits.

Invensys’ plant automation and information architecture, ArchestrA, uses software to extend the life of legacy systems, applies business goals, and preserves intellectual property, according to Mike Bradley, president of Invensys Wonderware (Lake Forest, CA). ArchestrA allows software applications to be rapidly assembled, rather than programmed, which means reassembling existing applications can create new ones.

With the first product, Wonderware Industrial Application Server, customers see “lower commissioning and maintenance costs,” Mr. Bradley says. Meanwhile, other Invensys products are being ArchestrA enabled; tool kits will be available before July, according to Kevin J. Tock, vp and general manager, ArchestrA business unit. (See sidebar for more on architectures.)

Mr. Jabbour says, “Siemens separates the standard engineering environment from the control platform. With this strategy, the automation portion of an application is transparent across all the different Siemens controllers,” so users can choose the platform to match the application.

AutomationDirect’s Mr. Ruland says, “The next-generation PLC local expansion I/O may use a high-speed proprietary chipset and network algorithms to ensure the expected synchronous I/O scan, but in a cost-effective, easy-to-use package featuring open control interface and cabling components.”

Mr. Komarek calls Phoenix Contact “the inventor of the first open fieldbus system, Interbus,” over 13 years ago. Today, he says, Phoenix Contact provides Multibus I/O systems, industrial PCs bundled with Phoenix IEC 61131 and Entivity flowchart software, OPC servers for logic control/ Ethernet devices, multiple protocols for Ethernet I/O, and, later this year, Microsoft Windows CE-based control. Phoenix Contact controllers always have been based on PC software and hardware technology.

“The ABB Industrial IT automation framework,” Mr. Hausler says, “enables easy integration with third-party applications that also use the same standards. Moreover, open standards and tools allow for the analysis and presentation of desired process information in easy-to-use and understand Microsoft formats, so that the customer can use this information for improved production decisions.

“Additionally, this openness is critical to providing incremental functional increases to our installed base,” he adds.

To start, says Mr. Miclot, Rockwell Automation is adding more “PC-like attributes, such as Web services and OPC DX, to its products. And we leverage de facto standards, such as Microsoft Windows, for our software solutions. We also support multi-vendor open fieldbuses like DeviceNet, ControlNet, and EtherNet/IP. Finally, Rockwell continues to participate in standards organizations and activities,” such as OPC, “to protect the interests of users by ensuring their freedom of choice in standards.”

Mr. Thomas says Eaton/Cutler-Hammer has products that support industry-wide standards with a high adoption rate, allowing for interoperability and compatibility with a number of devices on the marketplace. “Support of embedded technologies allow us to offer reliable yet extensible products. An example is our ePro line of PanelMate operator-interface products that support adaptability in balance with reliability.”

Mr. Areces of Schneider Electric draws a distinction “between something that’s widely used, like Microsoft Windows, and one that’s truly open, like Linux.” A similar network comparison can be made: “You have to pay to use Ethernet/IP, while Modbus TCP/IP can be used and downloaded for free.”

The market wants open technologies “because the goal is to make as many devices interoperable as possible; no matter how “open and free,” Mr. Areces says, many manufacturers and users are needed for technologies to be widely accepted.

For your next “open” implementation, may the information here help the experience more closely match a walk on an open prairie than dental work.

Other Control Engineering staff also contributed to this article.

Comments? E-mail .

Blending PC function in PLC form factor protects ‘secret sauce’

The trend of moving PC functionality into industrial settings continues with Tecla Programmable Data Processor from Online Development Inc. (Knoxville, TN). The hardware and software device combines a PLC-like form factor with PC-based functionality, with the ability to provide control, communications, and data acquisition.

Tom A. LeBay, director of marketing, Online Development Inc., says, “This technology helps you move from functional automation and controls into the optimization phase.” Microsoft Windows CE 3.1 operating system provides real-time results for many applications; a jitter test shows results in the 13-microsecond range, he says. In addition, using Microsoft .Net framework allows connectivity to higher-level systems. Programming can be through a software development kit (SDK), with a standard C compiler or application software and EZ-1131, which allows access through IEC 61131-3 languages.

The SDK allows an OEM to create value-added application, embedded and hidden to protect the secret sauce (proprietary source code, often carried over from legacy applications), adds Mr. LeBay. “Tecla integrates control and enterprise IT, delivering asset management, Web-hosted product support for end-user, best of class data historian, self-reporting diagnostics, and remote debugging.”

Embedded I/O is available, or Tecla can connect with Rockwell Automation Allen-Bradley I/O lines.

Automation architectures aim to insulate, preserve, maximize assets

Through familiar software tools and conventions, automation architectures aim to insulate, preserve, and optimize assets. They can include common hardware as well as software elements, some programming and development tools, and incorporate widely used industrial network and Internet-based abilities. While each originates from one vendor, there is some measure of “open.” Generally more than one vendor can use or build compatible products, and connect with common underlying technologies, such as Microsoft .Net and communication networks. Most have some measure of scalability across platforms (small to large, central to distributed, and stationary to mobile) and can accommodate a thin-client architecture or other tools that allow more central administration of software upgrades.

Vendors offering automation architectures include:

ABB—Industrial IT;

Emerson Process Management—DeltaV;

GE Fanuc Intellution—iCore;

Honeywell—Experion PKS;


Rockwell Automation—FactoryTalk;

Schneider Electric—Transparent Ready (formerly Transparent Factory); and

Siemens Energy & Automation—Totally Integrated Automation.

Author Bio: Mark Hoske has been Control Engineering editor/content manager since 1994 and in a leadership role since 1999, covering all major areas: control systems, networking and information systems, control equipment and energy, and system integration, everything that comprises or facilitates the control loop. He has been writing about technology since 1987, writing professionally since 1982, and has a Bachelor of Science in Journalism degree from UW-Madison.