Tag Archive: PID

Jun
10

Application of Kalman Filtering in DeltaV

A paper published in 1960 by Rudolf Kálmán “A New Approach to Linear Filtering and Prediction Problems” is the basis for the Kalman Filter. The Kalman filter has been successfully used in a wide variety of applications: • The guidance of commercial airplanes • Seismic data processing • Nuclear power plant instrumentation • Vehicle navigation …

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Jun
03

Robustness-Based Tuning

Before tuning calculations are applied in a control loop, it is good to consider how much the process gain and deadtime can change before the loop becomes unstable. In the DeltaV control system, this information is provided using a robustness plot that shows gain margin and phase margin as illustrated below. Information on this type …

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May
27

Commissioning PI Control – Integrating Process

When the control objective is to maintain the controlled parameter of an integrating process at setpoint under all operating conditions, then using PI (proportional-integral or proportional plus reset) controller, it is possible to automatically compensate for changes in disturbance inputs and maintain the controlled parameter at setpoint. However, the application of PI control to an …

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May
13

Easy to Apply Tuning Rules

Older control systems may not include tools that allow the PID tuning to be automatically established. In such cases, the following procedure outlined in Chapter 12 of Control Loop Foundation – Batch and Continuous Processes may be quickly applied to determine the tuning of a self-regulating process for PI control. In Chapter 4 of Advanced …

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May
06

On-demand Tuning Example

Control system manufacturers have adopted different technologies to implement on-demand tuning. Because these tools are designed to work in a noisy process measurement environment, the tuning results are usually better than those achieved through manual tuning techniques. To illustrate the features that may be included in on-demand tuning capability, the on-demand tuning capability of the …

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Apr
29

Selecting Control Response

After the process characteristics are identified, the information is then used to calculate the recommended loop tuning. The tuning rules used to derive controller parameters from process characteristics can be chosen as appropriate for the specific process and the desired speed of response. As addressed in Chapter 4 of Advanced Control Foundtion – Tools, Techniques, …

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Apr
22

Capturing Process Dynamics

When the on-demand tuning application resides in a DCS workstation, communications between the controller and the workstation can introduce variable delay and jitter in the observed process response. As addressed in Chapter 4 of Advanced Control Foundation – Tools, Techniques, and Applications, the process may be more accurately identified by distributing the on-demand tuning functionality …

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Apr
15

On-Demand Tuning

During the commissioning of feedback control based on the PID algorithm, the PID tuning parameters (that is, the proportional, integral, and derivative gain) must be set to specific values to achieve the best controller response to setpoint and disturbance input changes. To minimize process variations and the response time to setpoint and disturbance input changes …

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Apr
01

Addressing Loop Interaction

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 …

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Mar
25

Split Range Setup

One of the most common ways of addressing multiple process inputs is split range control. A splitter block, which appears as one valve to the PID block, can be used in the control strategy to define a fixed relationship between the controller output and each manipulated process input. In Advanced Control Foundation – Tools, Techniques, …

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