Human Centered Design Approach for Level Control

You may have heard about the focus on Human Centered Design (HCD) approaches across Emerson Process Management. The importance of this trend was highlighted in a recent Sound Off! blog post on Human Factors Engineering. This HCD focus over the past several years has led to the release of new technologies such as electronic marshalling and more approachable instrumentation diagnostics and monitoring.

I came across some information from Emerson’s Carter Cartwright, a member of the Fisher Valve & Instruments team, about another product released based on this HCD approach–the DLC3020f Fieldbus digital level controller. The objective of this development was to create a Foundation fieldbus-based level instrument that would improve level measurement and provide operators and maintenance technicians a simpler view into the operating and diagnostic information.

What was different from other technology developments was having several customers be a part of the development process. This collaboration began at the prototyping phase and continued through the concept-design review and testing phases. The Emerson support organization also participated in these design review workshops to include their support perspectives. These early interactions brought insights that the development team would not have had.

The issue with the existing approach to level measurement was that process temperature dynamics and fluid changes cause the observed vessel process variable (PV) to be different that the PV reported by the level transmitter. If the process fluid temperature could be compensated and a timely fluid selection to address feedstock or batches changes could be made, this would enable accurate and consistent PV measurement. It would also reduce ongoing maintenance from the diagnostics available by the additional temperature measurements.

Some of the innovations that came because of this HCD process included dynamic process temperature compensation for fluid density changes, a simpler approach to process fluid configuration changes that did not require calibration changes, and the addition of historical instrument calibration setup logs, which enabled process fluid information to be stored in the instrument and accessed in real-time.

Feedback from plant operations and maintenance folks led to the decision to include setup/calibration and process fluid historical logs in the level measurement instrument. The intent was to make the information more accessible for required maintenance and process changes. These instrument historical logs include calibration, setup and process fluid data.

This development is another example of forming a closer connection between the people who use and maintain the technology with the people who scope, design, develop, and test the technology. Making it a standard part of the technology development process should continue to provide products that are easier to start using with less training and simpler to maintain.

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