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The old batch automation system was based on custom code that was poorly documented. The new automation plan required the participation of operations personnel to generate functional and detailed operation design documents that could be used for a modular and fully ISA-88-compliant batch control system.
The project included a complete redesign to a fully compliant ISA-88 application using generic unit models. Control functionality was standardized for all similar components from equipment modules through unit models.
"Operators assisted in identifying key areas of the process where issues existed," says Digrys. "They provided insight and direction for the improvement of processes and procedures that could be included in the new ISA-88 batch design. They understood what portions of the previous automation could be used and what could be eliminated."
With the help of operators, display graphics were reworked and improved so that pertinent process data was visible and fully accessible. New batch Interlock displays using informative flow charts provided clear execution details that were easy to read and/or follow. These new displays proved to be an excellent troubleshooting tool for operations and maintenance personnel.
Digrys reports that the project was a success. "The number of operator human interface station graphics required for plant production was reduced significantly. The remaining graphics were enhanced by adding clearer automation messages that were pertinent to the operators. These detailed batch operator messages were key additions that provided real-time details of executing batch steps."
The new modular design provided a better means of handling process upsets during very critical phases. Plant production constraints were identified and corrected, providing improved quality while reducing batch cycle times and improving production rates. The redesigned system, using unit operations and procedures, provided the ability to construct and implement new recipes for different product grades without requiring an automation redesign.
Worsley Alumina includes a bauxite mine in Boddington, Australia, and an alumina refinery and port facilities near Collie, Australia. In 2006, User Centered Design Services began a project to upgrade the control rooms and the process control systems.
"Worsley started out with some very bad control room problems," reports Ian Nimmo, president of UCSD. "These included poor HMI design, alarm overload and bad ergonomics." Other problems included a lack of formalization of alarm management, no alarm philosophy and no HMI style guide or philosophy.
"Traditionally, the alumina industry hasn't tried a centralized control facility, even though we identified many common feed interactions and common utilities," Nimmo reports. "We proposed a centralized theater-style control room (see Figure 1), but management rejected the very thought of this. So we prepared a detailed comparison of control room strengths and weaknesses and a list of good practices and how to prevent bad practices." Worsley management eventually accepted the theater style control facility.
"We made significant improvements to their alarm management by first adopting a new alarm philosophy based on ISA SP 18 and EMMUA 191 guidelines," Nimmo says. "This reduced worst-case alarm floods from 13,450 alarms per hour to 11 alarms per hour. A major redesign of their HMI included moving away from traditional P&ID graphics to new HMI standards. This had a dramatic effect on operations as operators became proactive rather than waiting to respond to alarms and being reactive."
Worsley was one of Nimmo's first customers to experience the benefits of UCD. "We have since repeated this exercise in Europe at the Borregaard Bio refinery (Sarpsborg, Norway www.borregaard.com)," notes Nimmo. "They also captured similar benefits and are enjoying the low stress and improved situation awareness, as established by the ISO 11064 UCD philosophy."
Matrix Technologies in Maumee, Ohio, says it has provided hundreds of systems that were based on UCD. Here's how they use operators to help with a project, as reported by Stephen M. Goldberg, director of the industrial systems division.
Many clients have benefited from our project implementation strategy of operator input during the collection of information for functional specification and pre-shipment testing. There are usually many simple things requested by operators that they "need" to more efficiently run the process. This input is necessary where the operations team is much more familiar with a process than the client and integrator team implementing the system. One of the biggest benefits is quicker acceptance by the plant operations team, which results in a more efficient start-up.
"In a recent case we were duplicating an existing system based on a custom HMI, motion control and PLC," he says. "The customer wanted an off-the-shelf HMI and to upgrade the PLC and motion controller. By working with the operators we were able to come up with some definite improvements.
"The operators identified a screen that would help them more quickly find the system faults. The new equipment helped to eliminate many problems, but when the problems occurred, they were much easier to find and remove so that processing could be more quickly restarted. "
Many times the client is reluctant to involve this level of personnel due to greater complexity in gathering information from the "right" operator. Gaining the trust of the selected operator is also very important. You need to have a close mutual relationship to make sure the operator trusts you and that you can trust what input they are giving to be valid and helpful.
Dan Hebert is Control's Senior Technical Editor.