Online – 2002-12-01 – 2002-12-01

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By Staff December 1, 2002

At Control Engineering Online , you can access and register for 10 topical monthly e-newsletters; read ‘Today’s News’ each business day and fresh products weekly; explore 10 channels, show coverage, site search, and more.

Web-based downtime accounting aids lead, silver mining

To reduce unscheduled stoppages, protect its long-term investments, and save approximately $1 million in Australian dollars over two years, BHP Billiton (Melbourne, Australia) recently deployed Plant2Business framework from Citect (Sydney, Australia) at its Cannington silver and lead mine in northwest Queensland.

Plant2Business forms the basis of Cannington’s Downtime Monitoring solution. Its connectivity is used to publish information, while Citect’s Automation Servers identify downtimes. Plant2Business helped the mine overcome usability problems it has experienced with its legacy system, as well as find and analyze causes of downtime. Inquire online visit .

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Digital sensor upgrades electro-hydraulic servo actuators

M.E.A. Inc. (Elk Grove Village, IL) manufactures electro-hydraulic servo actuators for the oil, steel and power industries. To modernize its system that relied on a custom single-board controller and external amplification to control its hydraulic servo valve, M.E.A.’s engineers recently installed MTS Sensors Division’s Temposonics ASCII Protocol ServoSensor interfaced with an Eason Technology Intelligent Operator Interface (OI). The OI provides I/O point handling and communications for the system. ServoSensor is a control feedback device that reduces the system’s component count, while increasing flexibility and reliability.

ServoSensor also features a sensor and embedded closed-loop position controller in the same standard envelope, and allows multiple axis control of up to 16 axes per communication port. Also, built-in functionality can be accessed directly using predetermined PLC code. These capabilities include status monitoring, controller tuning, and a flexible command code, including target, velocity and jog functions.

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Gary Mintchell, senior editor,

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Making valve controllers/positioners smarter is smart business

Adding digital intelligence to ‘workhorse’ final control devices helps reduce process variability; increases production uptime; reduces operating costs; and improves safety. Positioners designed from the ground up to use digital technologies are generally known as digital valve controllers (DVCs).

With help from a variety of embedded discrete and analog sensors DVCs can improve present operations and anticipate future functioning. For example, Emerson Process Management’s (Austin, TX) Fisher division’s (Marshalltown, IA) DVCs include one discrete output and four discrete inputs with FOUNDATION fieldbus-certified function blocks.

Embedded sensors and on-board microprocessors help DVCs conduct diagnostic tests and manage digital communications. These diagnostic functions include final control device tracking parameters; DVC health parameter tests; final control device alerts; dynamic error band tests; drive and output signal tests; and predefined maintenance and signature tests. DVCs are also applied in partial-stroke testing emergency shutdown (ESD) valves and in fan/damper actuators.

In the future, DVCs will likely allow transparent integration of devices from many manufacturers into a common host automation system with help from the Germany-based ZVEI field device tool (FDT) standard. Other anticipated enhancements to DVCs are expected to include non-contact position sensing; autotuning; more sophisticated diagnostics and expert systems.

Dave Harrold, senior editor,

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