Loop control: Self-tuning device minimizes process disruptions

07/06/2007


In any process plant, there is usually a PID loop or two that needs more attention than others. Self-tuning controllers can often help that, but they frequently introduce their own peculiarities to a process. Microstar Laboratories has designed a self-tuning process that uses its standard hardware components and a software package that the company promises can adjust on the fly with minimal process disturbance.

( Read an article on self-tuning control strategies here and watch for a feature article: Fundamentals of Self-Tuning Control in the July issue of Control Engineering .)

Self-tuning controllers typically find out how a process works by manipulating their control efforts and seeing how the process variable responds. Different controllers use different approaches and some are more disruptive than others. Microstar’s data acquisition processor (DAP) board runs a real-time operating system (DAPL) that allows you to specify the behavior of the DAP and use a processing command, called a PIZST, to create a testing sequence.

The gain adjustments use Microstar’s iterative feedback technique. This approach reportedly estimates a gradient direction for loop tuning improvements using measurements rather than pure mathematical analysis. It does not determine specific gains to apply but produces incremental adjustments that improve existing gains.

Every DAP board runs DAPL, and can execute the PIZST command. An application based on a single board using a basic PID algorithm and optimized for multiple channel operation can be updated at time intervals as short as 0.05 milliseconds on every channel, without ever missing an update. DAPstudio, a Windows application you can use to control DAPL on any DAP board is available for download from Microstar’s Website, and you can download the PIZST command to test in a proof-of-concept experiment for your own application.

Detailed supporting documentation is available online , along with demonstration software for testing and evaluation. Moreover, you can order hardware for evaluation at no charge.

—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com , Control Engineering Weekly News





No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Sensor-to-cloud interoperability; PID and digital control efficiency; Alarm management system design; Automotive industry advances
Make Big Data and Industrial Internet of Things work for you, 2017 Engineers' Choice Finalists, Avoid control design pitfalls, Managing IIoT processes
Engineering Leaders Under 40; System integration improving packaging operation; Process sensing; PID velocity; Cybersecurity and functional safety
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Flexible offshore fire protection; Big Data's impact on operations; Bridging the skills gap; Identifying security risks
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
click me