More on Digital Valve Technology

March 11, 2008
Online Resources on Digital Valve Technology
Read our article A Dynamic Duo for more on digital valve technology.

Intelligent positioners improve valve integrity in critical ESD applications

At the Neste Oil Naantali refinery, specialized intelligent valve positioners work in conjunction with the Metso asset management software to continuously monitor and test the performance of the ESD valves to help ensure that the equipment in is working condition. According to Pauli Kaunisto, “The aim is to keep the emergency shutdown valves open for the whole six-year operating period. Neles ValvGuard continuously monitors and tests the performance of the ESD valves and ensures that that the equipment is in working condition.” The refinery also uses the technology to analyze safety risks through tests that help to decrease the probability of failure on demand, thus helping to maintain the required level of safety integrity.

Westlock Controls offers an innovative approach for testing critical ESD valves that does not use positioners. The company’s EPIC control transmitters perform the valve position sensing in a non-contact manner using an integrated Hall Effect sensor and magnet assembly with integrated low power solenoids for SIL 3 applications. This information is communicated back to the system via HART.

Emerging standards enable users to mix and match

In the past, to be able to take advantage of the full functionality of a particular vendors’ asset management software, a user often also had to use that same vendor’s intelligent positioners. Thanks to emerging standards, such as FDT and enhanced EDDL (eEDDL), users have much more latitude in selecting the specific intelligent positioners or other intelligent field devices that they install in their plants.

“Users widely acknowledge that one of the main benefits of fieldbus technology – and perhaps the benefit that provides them with the most long-term value – is the capability to use advanced device management applications in their host systems that can interact with performance diagnostics resident in their intelligent field devices. In the past, there’s been a problem realizing this benefit when the host and field devices came from different vendors,” says Charlie Piper, fieldbus product manager at the Foxboro Automation unit of Invensys Process Systems.

“Existing device description technology alone was inadequate, and until recently, there were no other standards. However, new FDT Device Type Manager fieldbus technology, combined with recent EDDL enhancements, have changed the picture. FDT technology is ideal for making advanced “plug-in” applications, including highly capable valve testing plug-ins, that attach to the host’s device management software in a standard manner. And through the efforts of the multi-vendor EDDL cooperation teams, the recent EDDL enhancements address one of the key limitations of earlier device description technology by allowing the device vendor to organize the data shown on simple live data screens on the host system and provide the menus to organize the user selection of displays,” Piper added.

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