Development and tuning of plant digital twins.

Enhancements to Mimic™ Simulation Software make it possible to simulate new process reactions and enhance safety checks for plant personnel training

A new release of Emerson’s Mimic™ Simulation Software makes it easier for plants to develop a more accurate digital twin. New modelling capabilities, usability enhancements and tuning options will help engineers more easily create, modify and integrate dynamic simulations for process improvements across the plant lifecycle.

The development of digital simulations of large projects can quickly get complex. Having to manually navigate through individual streams to tune factors such as temperature, pressure and flow on each process element of a simulated plant asset makes changing models time-consuming. Moreover, changing the format in which this data is collected used to mean taking the simulated process offline. New online stream-flow views in the latest release of Mimic significantly speed engineering changes. Users can quickly see all process elements in a single table with changeable parameters, making it possible to view and tune entire processes from front to back – all while keeping the simulated processes online.

The company has upgraded Mimic Advanced Modelling Objects with new blocks and objects to improve simulation – making simulation design easier for a wide range of industries, including oil and gas, liquefied natural gas, refining and petrochemical. Advanced Modelling Objects provide rigorous first-principles – dynamic models of plant unit operations such as those performed by separators, compressors, heat exchangers, valves, turbines, evaporators and more. Plate and frame heat exchanger and three-phase flash vapour-liquid-liquid equilibrium (VLLE) separation objects are now available, as are plug flow reactor objects that reduce the engineering time and complexity of model development for continuous processes in the chemical and hydrocarbon industries.

Organisations can also use new, simpler reaction modelling to more easily simulate reactions in a vessel. These new models offer increased flexibility in the use of reactions in design to automation engineers and organisations such as those in the specialty chemical and life sciences industries, which commonly use such medium-fidelity simulations. Users can create simplified reactions in engineering design – without the need for complex or private reaction data, or a background in kinetics and thermodynamics – to achieve desired results, such as the impact of a reaction on pH. The models also allow for faster simulation implementation because reproduction of complex chemical reactions is not necessary.

For plants that rely on standard operating procedures (SOP) to ensure safety and success in critical procedures such as start-up and shutdown, Mimic provides enhanced scoring features for training simulations. Trainers can modify scoring to prioritise actions that are critical in any SOP to ensure that all steps are properly completed in the correct order every time.

Mimic is now natively integrated with AspenTech’s HYSYS® Simulation Software, providing control platform integration and training functionality to the HYSYS simulation – making building and maintaining an operations digital twin much easier for the thousands of organisations already using AspenTech’s HYSYS software.

Good tuning for your pocket!

The International Society of Automation (ISA) announces that the newly released fourth edition of its Good Tuning: A Pocket Guide by Gregory K. McMillan has been updated to deliver more precise and optimal tuning for nearly all types of applications in the process industries. Greg McMillan (Right) being congratulated by ISA VP Publications 2009-10 Vitor Finkel  on receiving a Author's award some years ago. “This new edition is significant because it’s designed to meet more diverse tuning objectives and address more difficult tuning challenges,” says McMillan, a widely acclaimed and honored automation professional and author (and friend of Read-out!). “Readers will learn how to choose the most applicable tuning rule and associated parameters to make the most out of today’s powerful auto tuning and adaptive control software.” Central to the value of the new edition, McMillan says, is helping automation professionals unlock the full potential of proportional-integral-derivative (PID) controllers. “PID controllers have an incredible number of options and parameters besides tuning settings, but much of their potential and power have remained untapped,” he explains. “A key benefit of this newly updated book is that it provides the straight-forward direction and principle-based guidance to tune most controllers to their full capability and address a very wide spectrum of applications. “At the end of the day,” McMillan points out, “you need the means to handle the most difficult of tuning situations, deal with a window of allowable controller gains, meet different objectives, and achieve greater robustness. Understanding the interrelationships among the process, tuning, performance and PID features enables automation and process engineers to work together to improve process efficiency and capacity.” Instrument, process control and process engineers will appreciate the guide’s concise summaries, step-by-step descriptions of field-proven tuning procedures, table of typical tuning settings, overview of common valve performance problems, logic diagrams for trouble-shooting and other useful features.

Simplifying modern control system tuning! #PAuto #ISAuto

The International Society of Automation (ISA) tells us that the newly released third edition of its Tuning of Industrial Control Systems book simplifies modern control system tuning by eliminating mathematical complexity and addressing the real-world needs of control system technicians.

The authors, Dr Armando B. Corripio,  and Michael Newell, drew upon their project management experiences at major oil refineries to move away from the more academic approach of the two previous editions, and more simply explain how to improve control performance.

For example, the authors concentrate on just two rules for tuning—one that works best for common loops and the other for dead-time dominated loops.

Dr. Corripio, Professor Emeritus in chemical engineering at Louisiana State University (LSU), says that a more simplified explanation of tuning makes it easier to master today’s fundamental control techniques.

“By being less academic in approach, and removing a lot of the mathematical terminology, we’re able to improve understanding of how modern control systems work and help technicians better apply what they’re learning in the workplace,” he points out.

For instance, the third edition:

• Eliminates references to first- and second-order models since these terms are highly mathematical and reduce appreciation for the usefulness of the models.
• Removes the distinction between series and parallel proportional-integral-derivative controllers (PIDs) since most modern installations use the series version and there is little difference between the tuning of the two versions.
• Relies on a single set of tuning strategies: the quarter-decay-ratio (QDR) formulas slightly modified by the Internal Model Control (IMC) rules for certain process characteristics.

Corripio says the project management experience the authors gained at oil refineries gave them valuable insights and exposure to real-world issues and dynamics.

“I became better able to address a non-academic audience,” he relates. “When I co-wrote the first two editions, I was a professor and made much more of an academic mindset and perspective.”

Also unique to the third edition are:

• A chapter on auto-tuning software, a feature of most modern control systems that the authors contend greatly simplifies the acquisition of process data for effective tuning.  During their work at oil refineries, the authors utilized auto-tuning as a reference to guide selection of final tuning parameter for the controllers, and found it less disruptive than relying on manual processes.
• A thorough explanation of the control strategies of cascade, feedforward and decoupling—all of which are demonstrated with simulation examples.

All of the example responses were generated using simulation software to illustrate the tuning and show the differences of:

• Tuning controllable versus dead-time dominated loops
• Averaging versus tight level control
• Cascade control versus simple feedback control of a jacketed chemical reactor
• Feedforward control versus simple feedback control
• Decoupler control versus simple feedback control of a blender

Tune cascade loops from a web browser

ExperTune, now has the capability to tune cascade control loops directly from the web browser interface of the PlantTriage Loop Performance Monitor. This greatly streamlines the tuning process, according to ExperTune's Founder John Gerry.

The PlantTriage system monitors control system performance continuously, 24 hours a day. It automatically diagnoses and prioritizes process, control, and instrumentation problems. Integrated analysis and tuning tools improve plant results by focusing effort on the most critical issues.

Typical cascade control loops involve two instruments, two controllers, and a single control valve or variable-speed drive. Cascade controls are designed to reduce variation, by offering faster response to process upsets. The outer loop provides a setpoint to the inner loop. Unfortunately, says Gerry, "Most cascade loops in plants are poorly tuned, resulting in constant oscillations and interactions between the inner and outer cascade loop."

The new tools allow users to tune both loops, with a single bump test, directly from a web browser interface. Oscillations are eliminated because the PlantTriage tools select tuning constants that are outside the range of interaction. The new tools are also fully integrated with PlantTriage's "Active Model Capture Technology", so dynamic models and controller tuning can be developed based on normally-occurring events, such as operator setpoint changes.

Mr. Gerry, a member of the Process Automation Hall of Fame, who will be acclaimed an ISA Fellow at this years Automation Week (4th October in Houston), says "Cascade control, especially cascade tuning, is often mis-understood. These tools make it simple to tune loops the right way, which will help to stabilize plant operations, improving quality and energy efficiency."

Drag and drop I/O mapping with built-in oscilloscope for tuning and diagnostics

ORMEC has announced the global launch of MotionSet™, a powerful, easy-to-use proprietary commissioning software, designed expressly for use with new ORMEC XD-Series Indexer Servo Drives. This industry exclusive software tool can reduce conventional indexer setup efforts from hours, to minutes, with supplied pre-defined “load and go” application templates.

Designed to run on a Windows-based development PC, with XD-Series Indexer communications via USB or Ethernet connection, MotionSet™ uses a “drag and drop” interface to easily assign input and output functions to the drive's physical I/O points. The software allows programming of 32 individual motion profiles from a single screen via a user-friendly tree configuration, which can be mapped to I/O points, initiated via Modbus/TCP, and chained or looped together. The adaptable I/O, with 14 digital inputs and eight digital outputs, can be mapped to dozens of input and output functions. In addition to Modbus/TCP, Ethernet/IP, CANopen and Profibus-DP options will be available soon. MotionSet™ input functions can be used to trigger motions, change operating mode, clear fault conditions and synchronize motions, while output functions include ability to indicate drive status, motion status, motor position and timed pulses. Each motion entry has a data-entry screen for easy configuration.

The package includes a powerful, four-channel digital oscilloscope, enabling real-time viewing of all significant system values, event logging, extensive diagnostic capabilities, and graphic decoding of each input or output state for each capture sample. The scope’s time base can be set as low as 0.1msec, to facilitate viewing of the fastest events. There are over 40 triggers from which to choose, including motion conditions, fault conditions, encoder reference signals, digital inputs and outputs. For each of the four traces, the user can select from velocity, current, position, position error, bus voltage, digital inputs and outputs, encoder reference signals, and auxiliary encoder velocity and position. A built-in frequency analysis tool allows the user to isolate any system resonances, which can be eliminated using the built-in notch filter. In addition, it features a Motor Wizard, which allows users to simply non-standard motor integration and quickly commission unproven, third party motors. When a motor is connected, MotionSet™'s tuning screen and digital oscilloscope are used to fine-tune motor performance. Two available views include a Simple Mode, which allows for automatic measurements and adjustments, or an Advanced Mode, which provides access to current, velocity and position loop gains, as well as notch filters, command low-pass filters, feed forward filters and acceleration gains. A built-in drive exerciser allows the user override or control any or all digital I/O on the drive, while exhibiting key real-time drive data, allowing the user to clear faults or errors, or initiate motions in the motion table.

Also included is the ability to check the web for updates, which can be automatically downloaded and installed at any time. MotionSet displays complete version information for a connected drive and contains a utility for upgrading drive firmware. A Cam/Profile Designer utility can be used to generate simple tabular based cam's or profiles for use as a motion table entry, or the user can import data from a .csv file. Once program and motor data are loaded into the drive, configuration data is stored both in the drive and on a removable memory card, greatly simplifying software transfer, duplication requirements and hardware replacement needs.