Find the Right Engineering Tools

Most control and automation project planning and design methodologies follow a top-down define-and-design philosophy that begins with an overview and then uses an iterative process to add details until a thorough understanding of the control and automation requirements have been developed. The deliverable of this iterative process is the functional specification.

By Dave Harrold, CONTROL ENGINEERING September 1, 2001
KEY WORDS
  • Software

  • Function block

  • programming

  • Batch control

  • Calibration

  • Flowchart programming

  • Loop-tuning software

  • Object technology

Sidebars:
Improve project collaboration, lower costs

Most control and automation project planning and design methodologies follow a top-down define-and-design philosophy that begins with an overview and then uses an iterative process to add details until a thorough understanding of the control and automation requirements have been developed. The deliverable of this iterative process is the functional specification.

After the control system is selected and the implementation phase begins, the functional specification is implemented following a bottom-up philosophy. For example, I/O channel assignments for transmitters, valves, pumps, motors, etc. are usually implemented first. Next come interlocks and simple equipment logic, such as header and heat exchanger control that produce an implementation capable of allowing safe operation of the process in a manual or semi-automatic mode.

Subsequent implementation adds levels of continuous and sequential control to units (i.e., boilers, reactors, columns, absorbers, etc.), cells (i.e., distillation trains, continuous stirred reactor trains, etc.), and areas (i.e., utilities, fermentation, solvent recovery, etc.). (See ‘Organizing the control hierarchy’ diagram.)

Using this top-down design, bottom-up implementation process and following S88 standards places similar control and automation elements in like categories, each representing a component or subject- oriented view.

The ANSI/ISA S88 standard defines seven levels (layers) of an enterprise, but only
levels two through seven apply to the control hierarchy and are detailed within the
S88 standard. These six levels create a control hierarchy that can be mapped into
typical factory production operations and is being used by control and automation
system vendors, such as Siemens Energy and Automation and Yokogawa,
to manage control element relationships and views.

Changing the view

Anyone who has spent time watching operators perform their job know they only become interested in nitty-gritty detail when a problem occurs.

Generally operators scroll through displays that represent an area or cell level of the hierarchy looking for abnormal situations. It’s only when operators begin seeking an abnormal situation’s root-cause do they ‘drill down’ to lower levels of control and automation information.

Operationally oriented views of control and automation system data are often the preferred and more efficient means to maintain, troubleshoot, and retrofit the control system.

In other words, much of the time operators, system managers, and maintenance personnel require control and automation system information to be available in an operational-oriented view. (See ‘Component and operational views’ graphic.)

Components and Operational Views

Using familiar Microsoft Explorer visualization, control, and
automation software, such as Siemens’ Simatic PCS 7 and
APACS+ engineering system, allows users to rename and view
information in component and operational views.

Unified development environment

Not too many years ago, users wanting to implement microprocessor-based control and automation systems had to learn a plethora of development tools, mostly created from scratch by vendors and few of which worked well together. The result was often an implemented solution that was a nightmare to maintain, enhance, and upgrade.

No longer are system manufacturers required to develop tools from scratch. Today highly integrated development tools are constructed using standards, open-systems, and object-oriented technologies to deliver a unified development environment built around a core operating system architecture.

For example, Entivity’s (Ann Arbor, Mich.) Think & Do Studio uses Microsoft’s (Redmond, Wash.) familiar Visio graphical chart development environment and ‘smart’ objects to design, develop, test, debug, and deploy automation solutions.

What companies like Entivity, Intellution (Foxborough, Mass.), Rockwell Automation (Milwaukee, Wis.), USDATA (Richardson, Tex.), and Wonderware (Irvine, Calif.) have developed is the ability to provide a unified development environment constructed around the core architecture. For Entivity the architecture arrives as part of Visio, Intellution calls their architecture iCore, Rockwell builds around RSSql, USDATA’s architecture is Open Source Bus, and Wonderware recently announced plans to build all its products around ArchestrA (from combing the words architecture and orchestrate).

Advantages of developing products to work with a core operating system architecture are that it allows:

  • Leveraging enabling technologies, such as COM/DCOM, Microsoft .NET, etc.;

  • One-time development of object-oriented modules, such as alarms, messaging, communications, faceplate displays, etc., with the ability to reuse modules; and

  • Assembling modules into higher level application class objects with module inheritance.

‘Compared to suite-based software, products designed using class-based, object-oriented operating system architectures are more likely to be scalable and tweekable,’ says Steve Rubin, ceo of Intellution.

When control and automation vendors develop products using a class-based,
object-oriented architecture, users benefit by being able to develop, test, library, and
|manage standardized control object templates that maintain an inheritance relationship
even after the application is installed. User benefits are realized as lower cost of ownership
because changes need to be made in only one place and inheritance
handles updating each replicated element.

End-users benefit

What all this means to end-users is the ability to configure one instance (template) of an object, say an on/off valve, and use that object over and over while retaining the object’s inheritance abilities.

For example, device-specific parameters, such as tags, descriptors, on/off words, I/O channels, alarm values, etc., for all on/off valves could be in a spreadsheet, ODBC data source, or text file. When it’s time to ‘install’ the on/off valves, the library template version is replicated picking up parameter values during the replication process. (See ‘Class-based, object-oriented architecture’ diagram.)

Sometime after the on/off valves are installed, a desirable feature, say valve-closed status, is required. Thanks to inheritance, the changes are made to the library template, tested, and then replicated to every on/off valve that uses the template. Within seconds, every on/off valve on every graphic display is updated to reflect valve status (assuming the necessary field retrofits have been completed). Because of template replication, field-testing is reduced to just the wiring because if the software is correct in one place, it’s correct everyplace.

Despite providing very similar capabilities in basic tools, each vendor constantly seeks ways to differentiate products. For example, Invensys Software System’s (Herndon, Va.) Fox CAE (computer-aided engineering) tools support reusable and interchangeable library features and allow wholesale or select instance deployment. Fox CAE also provides the option of enforcing ISA tag naming conventions-one more means of ensuring database consistency.

Integrators, OEMs (Original Equipment Manufacturers), and third-party suppliers also benefit.

Using developer toolkits, integrators and OEMs can create and revise modules and/or objects, protect intellectual property against unauthorized changes, use new and revised modules and objects for future projects, and upgrade existing customer systems with new and revised modules and objects. These reduce total cost of ownership for customers and cuts vendors’ costs by supporting ‘a single version’ of a module or object.

A structured, object-oriented architecture allows third-party vendors to create specialty products that also employ a common database. (See ‘Toolset builds on class-based, object-oriented architecture’ diagram.)

A perfect example of developing and deploying a loadable function block from one company into the product of another is Schneider Electric’s (North Andover, Mass.) inclusion of Starling Associates (Norman, Okla.) Meter Manager gas-flow equation into select models of Modicon, Compact, and Micro controllers.

Developed by Starling Associates, Meter Manager meets requirements of AGA (American Gas Association) report #3 for orifice plate meters and the AGA-8 and NX-19 compressibility equations used for special gas compositions.

Schneider’s implementation provides end-users access to Meter Manager equations while protecting Starling’s intellectual properties.

Tools galore

Rare is the control and automation system vendor that completely meets every end-user’s every need. In fact, that’s exactly what several third-party vendors base their entire business plan on-filling a niche market space.

For instance, if you’re a Honeywell TotalPlant Solution or TDC 3000 system user seeking advanced alarm management software, Plant Automation Service’s (Houston, Tex.) AMO Suite and ProSys’s (Baton Rouge, La.) Dynamic Configuration Software are products designed specifically to meet that need.

Or what if the need is to design and troubleshoot fluid piping systems including property estimation and molecular design?

Take a look at Engineering Software’s (Lacey, Wa.) Pipe-Flo v.7 that includes a database of 550 process chemicals and industrial fluids to support predicting process fluid-vapor pressure and viscosity; an important consideration for properly sizing control valves and pumps.

With the recent partnership formed between Engineering Software and Molecular Knowledge Systems (Bedford, N.H.) Pipe-Flo v.7 now integrates with Cranium to calculate physical properties of pure chemicals and mixtures using a variety of estimation techniques further improving predicted results.

Getting back to basics, a niche product designed to manage logging-printer messages is LogMate from TiPs (Georgetown, Tex.). LogMate collects ASCII text data from just about any device, parses the data into an ODBC database, and makes it available for viewing, searching, analyzing, notification, and trouble-shooting.

Loop-tuning tools are another area where niche products have been successfully integrated with control and automation system supplier products. For example, ControlSoft’s (Cleveland, O.) Intune and ExperTune’s (Hurbertus, Wis.) process loop monitoring and tuning software connect with or are an integrated part of systems from ABB, Emerson Process, GE Fanuc, Honeywell, Omron, Rockwell Automation, Siemens, Westinghouse, and others.

If specifying and managing field instrumentation records are an important part of plant design, then Intergraph Process and Building Solution’s (Huntsville, Ala.) Plant Design System (PDS) and Intools solutions could be of help.

PDS creates and maintains an accurate database of information required for regulatory compliance, operations and maintenance support, and retrofit projects. Intools integrates with PDS and permits drilling deeper into plant systems to manage specification sheets, wiring lists, loop diagrams, and a variety of reports for field instrumentation.

Engineering tools designed around a class-based, object-oriented architecture
permit using a variety of tools to develop and maintain a common control and
automation database. This approach allows users and integrators to develop
reusable objects and permits third-party vendors to develop special add-on tools
while protecting intellectual knowledge.

More tools

A benefit of fieldbus technology is the opportunity for suppliers to embed intelligence in the form of self-diagnostics and usage information in field instrumentation. Intelligent field instrumentation provides an opportunity to move from emegency to informed (proactive) maintenance practices. But doing so means information contained in intelligent field devices must be collected, analyzed, and acted upon.

Enter yet more integrated software tools.

Emerson Process (Austin, Tex.) calls it Asset Management Software; Smar (Sertaozinho, SP, Brazil) calls it Syscon. These engineering tools allow browsing intelligent fieldbus connected instruments to check overall status, calibrate the instrument, reconfigure parameters, conduct network maintenance, and determine the overall health of the fieldbus and connected devices.

Armed with real-time, field-relevant information, operation and maintenance personnel are better prepared to make informed equipment maintenance decisions.

If after all this you’re still not sure what you need in the way of software tools, try visiting Software Toolbox (Matthews, N.C.) online store at www.softwaretoolbox.com. It’s like wondering up and down the aisles of Sears’ tool department. You’re likely to find things you didn’t even know you needed.

Organizing the Control Hierarchy

ANSI/ISA S88 Typical factory production Sample Siemens Yokogawa
Source: Control Engineering with data from ANSI/ISA S88, Siemens, and Yokogawa
1 Enterprise
2 Site Factory PHL-East Project Site
3 Area Department Utilities Plant Area
4 Process cell Line Boiler 1 Unit Cell
5 Unit Unit Combustion Function Unit
6 Equipment module Equipment Air Position Equipment
7 Control module FIC-1-1 Element Element

Improve project collaboration, lower costs

Of all the things the Internet has achieved, reducing time and boundaries are possibly the most significant.

Near instant two-way messaging and document sharing allow people to be scattered to the four winds yet stay in-touch. But the more people involved and the longer they need to work together, the more project-like the collaboration becomes and the more apparent the need for sophisticated organizational management and reporting tools.

In the control and automation arena, customer, supplier, and integrator project teams are seldom in the same time zone and frequently not on the same continent. To overcome the difficulties of time and space, project teams rely on project standards, extranets, e-mail, teleconferences, videoconferences, and face-to-face meetings.

Project standards almost always vary from customer to customer and often from project to project within the same company making strict adherence difficult. All other items listed are forms of communication with some being more effective than others.

The folks at Entivity (Ann Arbor, Mich.) recognized the challenges facing distributed project activities and have created a web-based project collaboration tool called Automation ProjectNet.

Automation ProjectNet provides a framework for a completely distributed ‘design-to-deployment’ project solution that incorporates real-time project-analysis capabilities.

It has ability to provide online viewing and ‘red-lining’ of over 250 file formats combined with a library of standardized templates designed for automation industry processes and workflow. Automation ProjectNet automates and helps manage project activities, such as bid request, change orders, document exchanges, schedules, notifications, revision control, punch lists, and test planning and results.

A recurring problem with traditional project management methodologies is when the project completes and operations take over, much of the knowledge about why things were done a certain way become lost. With Automation ProjectNet, project files can remain accessible, be kept up to date, and provide near instant access to ‘as-built’ documentation-an important consideration in regulated industries.

For more information on Automation ProjectNet, visit