Each day, the aquarium pumps nearly 3 million gallons of seawater through the facility to simulate the natural ocean environment. At night, incoming seawater is unfiltered, bringing in plankton, seaweed spores, larvae, and other miniscule food sources for fish and plants. During the day, however, the raw seawater must be filtered to keep the tanks and water as clear as possible for visitors.

Fishing for a solution
When the aquarium opened in 1984, most life-support systems and filtration were handled manually. This system was vulnerable to variances in staffing schedules and human error, and required staff to be on-site 24 hours a day to make sure that all aquarium processes ran smoothly. As the aquarium expanded (opening its Outer Bay Wing in 1996 nearly doubled the exhibit space), one realization became clear—the aquarium would have to dramatically increase on-site staff or use advanced automation technologies to maintain required operational efficiencies.

The Monterey Bay Aquarium had one primary goal when it evaluated automation companies—the new system had to be a seamless single-vendor solution from processor to operator interface and beyond. This would ensure that all components of the system worked together and would be scalable for future enhancements. The system also had to be built on open technologies for the same reasons. Because the aquarium systems run 24 hours a day, its operators had to be able to learn, operate, and maintain every component without any outside technical support, in case problems occurred outside normal technical support hours.

"Increasing staff was not the best option for us; we wanted to shift our efforts from routine operations to preventive maintenance," says Mike Brigham, systems control engineer for the aquarium. "Automation would give us more consistent controls and allow operators to spend more time optimizing processes, rather than just keep them up and running."

After evaluating several vendors, the aquarium chose Rockwell Automation (Milwaukee, Wis.) and system integrator Pipeline Systems Inc. (PSI). PSI mapped out a new control system, eventually tying in nearly 30 Allen-Bradley SLC 500 programmable controllers to run various components of life support, as well as the aquarium's heating/ventilation/air conditioning (HVAC) system.

A whale of an idea
The control system now provides automation, monitoring, and alarming for all principal parameters of the life support system, including temperature, flow, pressure, dissolved oxygen, pH, ozone injection, and ORP. It also controls repetitive tasks like backwashing sand filters for filtration, boiler and chiller loop control for temperature control, ozone generator control, and oxygen injection control to maintain oxygen levels in the water.

In addition, the SLC controllers handle exhibit lighting for visitors on the other side of the aquarium glass. The controls automatically turn on and off all the exhibit, public space, emergency, and housekeeping lighting to conserve power and create task lighting that enhances each exhibit area.

Two control rooms at the aquarium serve as dual headquarters for operators, with operator interface stations running Rockwell Software RSView32 human-machine interface (HMI) software on the Microsoft Windows NT operating system. RSView32 allows control operators to monitor every control parameter from either control room location, and provides trending information and alarm notification. Mr. Brigham is upgrading the system from Rockwell Software's ControlView HMI DOS to take advantage of new modules available for RSView32. He recently added the new RSView32 Messenger module, a remote notification add-on that seamlessly integrates into RSView32 through the HMI's Add-On Architecture environment.

Quick notification of alarms is critical at the aquarium. If a system failure occurs and is not corrected quickly, millions of dollars in plant and animal life could be at risk. Before using Messenger, operators were required to stay on site so alarms could be heard and corrected within minutes.

"The Messenger module automatically alerts the operator on duty by sending an alarm directly to a pager," Mr. Brigham said. "The ability to receive alarms off site has allowed us to cut down from 24-hour on-site support to 18 hours. Now during off-duty hours, the operator can be paged at home and access the control system remotely through third-party software."

For some alarms, like a utility power failure, operators must still return to the aquarium, but most alarms can now be handled through the remote interface with Messenger. In addition to alarms, Messenger can provide status information on processes for off-duty operation or supervision of multiple processes.

Schools of information
A main data server logs information collected from control devices across the aquarium via a local area network and stores it for use by other departments. Internal departments such as Applied Research and Animal Husbandry archive certain information for biological diagnostics research, and outside educational institutions use some of this information for research.

This continuous data acquisition allows the biological department to automatically track critical information that was previously tracked manually. Also, the biological department can now consistently determine feeding patterns, temperature variations, and water quality changes to help maintain the best aquarium environment possible.

The control system has permitted the aquarium to easily install and maintain total redundancy on a number of critical life support systems. This ensures that normal operation can continue on these systems, even in the event of a primary systems failure with no operator backup. Remote alarming can notify an operator of any failure, but having redundant systems eliminates the possibility of complete failure, in case operators cannot get to the aquarium quickly.

"The automation systems now in place have allowed the aquarium to increase in size, increase efficiencies, respond more effectively to alarms, and collect information in a more consistent manner," Mr. Brigham says. "Since inception, the aquarium has grown nearly 300%. However, with automation technologies, our control systems staff has only increased about 20%. Now, the time we spend with the system is focused on perfecting it, rather than operating it."

Mr. Brigham and his staff continue to upgrade the current control system. Every few years the aquarium adds new exhibits or renovates existing ones, which requires modifications in the control system. As older exhibits are renovated, older SLCs are swapped out for new, software is updated, and new sensors are added. Entire exhibits can be added or moved, which requires flexibility from the systems and Mr. Brigham's staff, who must keep up with all the changes. In addition to regular modifications, he also plans to install new controllers in remote off-site buildings that have previously been stand-alone systems, tying even more areas to the system.

Control Engineering        November 2000