Tag Archive: performance

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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Mar
04

Addressing Incorrect Tuning

A Loop tuning has a significant impact on control loop utilization and performance. Controller tuning parameters can be easily changed over a wide range to adjust loop operation for various process requirements. However, some expertise in tuning is required even when advanced control tools are used, and there is a chance that the behavior of …

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Feb
18

Improving Control Utilization

When the utilization of a control loop is found to be low during normal plant operation, the measurement or control problems that prevent the control loop from functioning in its normal (designed) mode of operation should be further explored. In Chapter 3 of Advanced Control Foundation – Tools, Techniques, and Applications we outline the steps …

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Feb
11

Control Utilization

It can be shocking to examine control utilization in a plant where performance tools have not been installed and/or not used. For example, in the mid-1980s a control survey was conducted at a major pulp and paper plant where the control system had recently been updated to the latest distributed control system. At that time …

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Feb
04

Evaluating Control Performance

A plant operator is usually responsible for managing one or more process areas, with (potentially) hundreds of control loops and process measurements in each area. The operator’s job is made easier if the control loops in these process areas are in automatic mode and can compensate automatically for disturbances and maintain the operating conditions the …

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Jan
14

Evaluating Control System Performance

The operation of industrial process control systems often involves the control of multiple unit operations with hundreds of measurements and control loops, as illustrated below. Although these systems are designed to automatically archive operational data in an historian, it is time consuming to examine historical data to determine if there has been a change in …

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Feb
27

Control Using Wireless Devices – Namur’s Interest

Earlier this year, the Namur Working Group 4.15 invited Emerson and four other major manufactures of distributed control systems and wireless transmitters to present their activities and R&D work concerning closed loop real time control applications based on wireless technology. In this meeting with Working Group 4.15, each vendor was given one hour for their …

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Jul
25

Commissioning Control Systems – Valve Performance

As addressed in my July 18th blog, when a valve positioner is installed on a valve actuator, as long as it is functioning properly it will automatically increase the actuator pressure until the valve moves to a position that matches that requested by the control system. Feedback of the stem position is used by the …

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Jul
18

Commissioning Control Systems – Valve Positioners

When commissioning a control system, it is important to be aware of whether a regulating valve is equipped with a positioner. If a valve does not have a positioner, then as part of loop commissioning it may be necessary to install a positioner on the valve to achieve the desired control performance. For various reasons, …

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Jan
31

Cascade Control

Cascade control may be applied when a process is composed of two or more (sub)processes in series. To apply cascade control, the output of each of these processes must be measured. The input to the first process is directly manipulated. Since the output of each process in the series is the primary input of the …

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