Simulation software reduces commissioning time

It seems everywhere you look, control and instrumentation suppliers are touting ways a product and/or service reduces time-to-market. Sometimes the hype seems to indicate commissioning of the control and instrumentation system need not begin till about an hour or two before the finished goods are due at the customer site.

By Dave Harrold March 1, 2003

It seems everywhere you look, control and instrumentation suppliers are touting ways a product and/or service reduces time-to-market. Sometimes the hype seems to indicate commissioning of the control and instrumentation system need not begin till about an hour or two before the finished goods are due at the customer site.

Of course we know that’s not really the case, nevertheless, such claims cause us to grimace just a little.

This one is different

Using simulation software to test and validate that a control strategy design does what it’s intended to do certainly isn’t new. However, including a line item in a project specification to develop and use simulation software often is seen as a ‘luxury’ and thus becomes one of the first things cut when project budgets need to be ‘revisited.’

Realizing the need to overcome the luxury stigma often associated with simulations, Mynah Technologies (St. Louis, MO), working in concert with Emerson Process Management (Austin, TX), approached development of its mimic process simulation software with a different focus and philosophy. Mynah software gurus designed and constructed mimic to meet four principles.

Mimic must:

Be easy to setup, configure, and use;

Support digital fieldbus technologies;

Support multiple hardware platforms; and

Simplify commissioning, validation, and training activities.

Make it easy

Almost without exception, the easier a product is to use, the more robust and sophisticated that product’s foundation and underlying structure needs to be.

In the case of mimic, that means some pretty sophisticated software technology is lurking in the background, because mimic is easy to use.

Mimic uses non-intrusive, auto-sensing technology to detect the fieldbus technology in use-FOUNDATION, HART, AS-i, Profibus DP, and/or DeviceNet-and applies the appropriate characteristics and capabilities for each connected I/O device.

For example, if auto sensing detects that PID control resides in a control valve, mimic simulates the transmitter, the PID control algorithm, and the valve. If PID control resides in the controller, mimic simulates only the transmitter and the valve.

Despite close ties with Emerson Process, Mynah designers ensured mimic provides similar capabilities across multiple platforms, including Rockwell Automation’s Allen-Bradley PLC3, PLC5, and SLC; Emerson’s DeltaV; GE’s Series 6, 90-30, and 90-70s; Schneider Electric’s Modicon 984 and Quantum; and Siemens’ TI 565.

Mimic’s chief architect, Nobin William, acknowledges that mimic’s ever-growing ‘wish list’ includes additional control-system interfaces. ‘What really slows down our controller interface development efforts is a reluctance of suppliers to provide us the information we need. We often must reverse engineer the interface, and that adds a lot of time,’ says Mr. William.

Keep it simple

Anyone who has commissioned a control system using multiple people, walkie-talkies, I/O drawings, and software configuration documentation can appreciate the productivity of being able to narrow hardware, software, and wiring problems to just one domain.

Mimic helps minimize potential problem sources by providing a complete simulation of everything except field wiring and physical device presence. And, because mimic is non-intrusive, disconnecting from simulation and reconnecting to live I/O points doesn’t introduce new unknowns.

Also, because the product can mimic digital field-device characteristics, a multitude of configuration and software errors can be detected and corrected before commissioning begins. For example, if the controller configuration expects a specific (tagged) intelligent device to be at a particular field location, and it’s not, it shows up as a mismatch within seconds after connection and power up. Not seemingly a big deal, unless you consider that two flowmeters with different ranges and/or different wetted materials might have been interchanged during installation.

To address the tedious, time-consuming task of graphic, alarm, and database testing, mimic provides user-defined testing scripts; a useful addition in the enforcement of good software development practices that requires software designer/implementers not test their own work.

Training support

Anyone who’s experienced starting up a complex process with and without extensive operator training can understand the benefit pre-startup training delivers.

Three common training simulation problems mimic designers solved are:

Instructors needn’t be process, control, and/or software engineers;

Training scenarios can begin with the process already at steady state using mimic’s snapshot and restore feature; and

Instructors can mix lecture, simulation, and question/answer periods using mimic’s freeze, resume, and real-time execution multiplier features.

From a unit manager’s viewpoint, commissioning is far more than the time it takes to hook up the instruments and control system. Unit managers consider commissioning as all the time and resources expended before saleable products are produced. Mimic helps reduce commissioning time measured by unit managers; and when unit managers are happy, everyone’s happy.

This software review is based on mimic version 2.6. System requirements include Intel Pentium III, 128 MB of RAM, and VGA or Super VGA monitor. For more information on mimic visit www.mynah.com

-Comments? E-mail Dave Harrold at dharrold@reedbusiness.com