Fieldbus lays firmer foundations
15 Jan 2000
While the seemingly never-ending arguments about fieldbus standardisation surface once again (see page 9), the worldwide process industries quietly get on with the job of choosing what they believe are the best systems for their particular application.
This not exactly novel approach to system specification has already resulted in Profibus proponents claiming an 'avalanche' of orders for the Profibus-PA process version, including several in Germany and the UK. These include Shell Oil's lube plant in Hamburg, and Polymer Latex's styrene storage plant.
Meanwhile, on the other side of the world, supporters of the Foundation fieldbus can point to its first use in the important process sectors of oil and gas, and pulp and paper.
At ARCO's West Sak oilfield on Alaska's North Slope, a previously unviable field has been made productive by the use of new recovery techniques and smart instrumentation standardised on Foundation fieldbus. Started up last December, the first four wells of the 50-well field are linked by twisted-pair cabling to a control room 400m away.
Fieldbus equipment at this site includes Rosemount Model 3051 pressure transmitters, El-o-Matic ELQ electric valve actuators, a Fisher-Rosemount DeltaV process automation system, and integrated field device calibration/configuration tools.
According to ARCO's site instrument and control engineer Duane Toavs, existing systems in the area were based on a Bailey DCS system and Siemens PLCs. But when bids were in for the new project from five major suppliers, the Fisher-Rosemount proposal best met ARCO's criteria for the normally unmanned site.
'The remote diagnostics of the fieldbus system was a huge selling point,' says Toavs. 'We've standardised on Foundation fieldbus technology to reduce costs for engineering, installation, operation and maintenance.'
By being able to install valves and transmitters at the wellhead, rather than in protective buildings to cope with the sub-zero temperatures, ARCO saved millions of dollars. Considerable savings were also made during the start-up phase when skilled programmers, who would take up to four days per wellhead site to configure the Bailey DCS/Siemens PLC systems, took only four hours with the DeltaV/fieldbus system.
On the other side of the continent, the first Foundation fieldbus application for the pulp and paper industry has been successfully started up at Avenor's Gatineau mill in Quebec, Canada. Portions of the Kraft pulping process are controlled by PID algorithms running in transmitters and digital valve controllers that are part of a Fisher-Rosemount PlantWeb system.
Mill manager Patrice Cayoutte says: 'We made a strategic decision to use Foundation fieldbus because we believe the technology is very promising and we wanted to get a head start on learning how to put it to work for us. For example, we see the potential to eliminate downtime by using F-R's advanced valve diagnostics through fieldbus.'
