Tag Archive: interaction

Apr
01

Addressing Loop Interaction

Interactive Loop Example

In some cases, the manipulated parameter of one control loop can impact the controlled parameter of another control loop as illustrated below. To allow both loops to operate in automatic mode, loop interaction is most often addressed by simply detuning one of the control loops by reducing the proportional gain. The valve (or another final …

Continue reading »

Dec
05

Commissioning Highly Interactive Process

Commissioning Highly Interactive Process

At Emerson Exchange, 2011, I had the pleasure of working with Eric Chen, Research Associate, Pickle Research Center, University of Texas at Austin SRP and Willy Wojsznis, Senior Technologist, Emerson Process Management, to host a workshop that addresses commissioning of a skid process that is characterized by a high degree of process interaction. The size …

Continue reading »

Sep
12

Commissioning Control Systems – High Order Process Response

Heater example

The process response to a change in disturbance or manipulated input is often the result of many mechanisms working together and interacting: heat transfer, momentum, inertia, air capacitance in an actuator, and so on. The combined effect of these different mechanisms constitutes a higher order process response. However, response of a self-regulating process often closely …

Continue reading »

Sep
05

Commissioning Control Systems – Closely Coupled Process

Flash Skid Process for CO2 Recovery

In a previous blog, I addressed some of the challenges of commissioning a multiple input/multiple output (MIMO) process that is characterized by process interaction. Also, in Chapter 12 of Control Loop Foundation – Batch and Continuous Processes  we address the special considerations associated with tuning an interactive process.  In such a process, each manipulated input may impact …

Continue reading »

Aug
15

Commissioning Control Systems – Process Interaction

Decoupling Process Inteaction

In many applications, the process equipment is characterized as having multiple manipulated inputs. This type of equipment configuration is often referred to as a multiple input/multiple output process. The process control consists of multiple PID blocks where a process output and process input pair are associated with each PID. The challenge in designing and commissioning …

Continue reading »

Jun
06

Addressing Difficult Dynamics, Process Interaction

Primary Reformer Temperature Control

Single-loop and multi-loop control may be used to address a wide variety of control requirements. However, if a process is characterized by extremely long process delays or by a high degree of process interaction, then other control techniques may be required. In Chapter 16 of Control Loop Foundation – Batch and Continuous Processes, pulp bleaching …

Continue reading »

Feb
24

Opportunity for Minimizing Loop Interaction

Aggressive action by one loop can upset another loop while attempting fast tight control. The most common example involves loops sharing a common utility or raw material resource, often in piping branches off of a header. The enhanced PID for wireless (PIDPlus) can eliminate the limit cycles that would spread throughout the system. The addition …

Continue reading »