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Automation industry articles from ISA

Fig. 1. Block diagram of a typical PID control system.

Robust PID controller design for non-minimum phase time delay systems

Abstract: A robust PID controller for a non-minimum phase system subject to uncertain delay time is presented in this paper. Utilizing the gain-phase margin tester method, a specification-oriented parameter region in the parameter plane that characterizes all admissible controller coefficient sets can be obtained. The PID controller gains are then directly selected from the parameter […]

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Fossil Fuel Committee Publishes Functional Requirements

Organizations that operate fossil fuel plant control room simulators deal with different operator and training practices. Yet they share common goals when it comes to personnel safety, maximum equipment availability and lifetime, and ensuring efficient operations. When the ISA77.20 subcommittee reviewed the existing standard, ANSI/ISA77.20.01, Fossil Fuel Power Plant Simulators: Functional Requirements, they updated many […]

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security hand on keyboard

Uninterruptible Power Supply Technology and Cybersecurity

The recent number of cyber-attacks and their level of sophistication have demonstrated the inadequate network security measures employed by many large corporations, government, and military agencies. Time is on the hackers’ side. They only have to find one unsecure computer or device on a segment of a corporate or governmental network, and they can use […]

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Fig. 1. Block diagram of a cascade control system.

Improving performance using cascade control and a Smith predictor

Abstract: Many investigations have been done on tuning proportional-integral-derivative (PID) controllers in single-input single-output (SISO) systems. However, only a few investigations have been carried out on tuning PID controllers in cascade control systems. In this paper, a new approach, namely the use of a Smith predictor in the outer loop of a cascade control system, […]

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petrochemical co-workers working in the plant

Promoting Operator Effectiveness

Operator effectiveness is often an overlooked area that can improve the performance and safety of your control system or plant. Yet operator effectiveness is one of the key elements for running a safe, efficient, and profitable plant. Research shows worldwide process industry losses because of unscheduled downtime and poor quality can exceed $20 billion. Of […]

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The key MEMS sensors today are accelerometers, gyroscopes, and pressure sensors.

Making Sense of Micro Electro Mechanical Systems or MEMS

Micro Electro Mechanical Systems (MEMS) describe a type of device or sensor as well as a manufacturing process. MEMS sensors incorporate tiny devices with miniaturized mechanical structures, typically ranging from 1-100 μm (about the thickness of a human hair), while MEMS manufacturing processes provide an alternative to conventional macro-scale machining and assembly techniques. MEMS development […]

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Fig. 1. Input vector for TITO process.

Guidelines for the tuning and the evaluation of decentralized and decoupling controllers for processes with recirculation

Abstract: This paper gives guidelines for the pairing, the time response specification, and the tuning for processes with recirculation when decentralized controllers are used. This selection is based on the condition number, which is an indicator of the process directionality, and on the generalized dynamic relative gain (GDRG), which is a measure of the interaction. […]

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