Seattle Gains State-of-the-Art SCADA System

Y2K. We’re all aware of it, but do we really know what it could mean to our daily lives? According to Bob Bennett, Chairman of the Senate Select Committee on Y2K, there doesn’t seem to be anyone who can fully answer that question.

“I can’t tell you, are we going to be all right?” said Bennett at a Y2K Task Force Public Forum. “I haven’t got any idea. I can make some guesses and they may be educated guesses, but until the whole system really goes through this there’s no way really, to test it in advance. Everything is so interconnected. The power grid is going to work. Of course the power grid is going to work. That’s based on the assumption that the telephones will work. And the telephone system is going to work, and that’s based on the assumption that the power grid is up. And so on, all the way through."
 John Hamre, Deputy Secretary of Defense, agrees.

 “The Y2K problem is the electronic equivalent of the El Nino,” said Hamre, “and there will be nasty surprises around the globe.”
 Amazingly, it seems that industrial automation is more sensitive to incorrect dates than had been originally anticipated.

 “At each one of our factories there are catastrophic problems,” said Ralph Szygenda, Chief Information Officer for General Motors, speaking with Fortune Magazine. “When we tested robotic devices for transition into the year 2000, for example, they just froze and stopped operating.”

The American Waterworks Association has recently released a survey. It found that many of our nation’s municipal water providers are not prepared for the year 2000. Another survey conducted by a national wastewater association found that only 35 percent of the survey’s respondents expected to complete Year 2000 repairs. During an American-Canadian meeting held in February of this year it was revealed that ten percent of the large urban water suppliers in the U.S. will not be Y2K compliant when the millennium arrives.

 We’ve all read the news recently concerning the computer glitch that happened during a Y2K test in Los Angeles. At the Hyperion Treatment Plant over 2,000 alarms were triggered in the first hour of the test. It took officials an hour and 15 minutes to realize that nearly 3 million gallons of raw sewage had spilled into a local park.

 The City of Seattle’s Public Utilities (SPU) has a different story to tell. Early last year they completed an analysis on the current pumpstation equipment relative to Y2K, and decided to replace their outdated system with a SCADA system connected to smart PLCs or RTUs.
 Dan Pflager, Senior Software Engineer in charge of embedded systems Y2K for SPU, conducted a Y2K analysis on the pumpstation equipment and found problems in the software and hardware as well. He also reported that much of the field equipment was obsolete or unsupported.

 Regulatory Requirements
 SPU also needed to meet new regulatory requirements issued by the Department of Ecology. These regulations required that the current pumpstation network be able to quantify an overflow at any given permitted site. This was not possible with the older monitoring and data collection equipment in place at the time. When it was installed in the 1980s, data collection was expensive, forcing officials to limit data collection parameters to only minimal data necessary to perform SPU’s current business and permit requirements..

 Designing the New System
 SPU decided that in order to meet both the regulatory requirements and avoid any potential for a Y2K incident, a new system was in order. One that could provide more data from their field equipment and add intelligence to the remote sites to compute and log lift station flow rates and increase the accuracy of data during overflow events.

 Robert Schommer from Systems Interface Inc. and Pat Murphy of Rockwell Automation put their heads together and designed just such a system.
 “The customer preferred a nationally recognized, name brand solution with local distribution and required Modbus protocol,” said Schommer, Municipal Business Manager for Systems Interface. “The solution had to be PLC compatible and the customer preferred the Allen-Bradley hardware, yet A-B couldn’t accommodate the need for Modbus.”

 ProSoft Steps In
 “That’s where ProSoft Technology stepped in,” said Doug Sharratt, President and Lead Developer for ProSoft. “A large number of SCADA projects in the Oil & Gas and Water/Waste Water industries have been specified with the Modbus protocol. The ProSoft RTU-5/03 Processor, developed jointly by ProSoft Technology and Allen-Bradley, is aimed specifically at these opportunities. It is an Allen-Bradley SLC 5/03 processor that has been modified to include the Modbus Slave protocol.”

 Once the Modbus protocol is activiated, a Modbus host can read and write data from all the common Modbus data types. In addition, support has been provided for the transfer of Floating Point data, which optionally uses the ‘Enron’ addressing range. A host can also access the processor Status File S2 to remotely monitor the health of the unit or do such things as setting the real time clock.
 “SPU couldn’t compute station flow rates, including overflow events, with the past system,” said Schommer. “Now they can track the well level and integrate it over time to accurately compute and log well inflow, outflow and, how much overflow has occurred.”

Seattle SCADA

More Control, More Information
 The new telemetry system consists of a hot backup, redundant, dual processor headquarter master station talking to 72 Remote Telemetry Units (RTU) at each of SPU’s sewer pump stations.

 “ProSoft’s Modbus Communication Modules function independent of the PLC, sharing the task of communications and allowing the processor module to concentrate on control and data functions,” said John Stephenson, Project Manager for Systems Interface.
 The RTUs monitor the pump station activities and control the operation of the sewage removal equipment, which consist of either pumps or air compressors. The headquarter master polls each RTU via a modem connection and staff at the headquarters monitor the status and alarms in order to track pertinent data and be able to respond to emergency situations. This is far different from the previous system, which couldn’t track or control any station flow rates.

 “Technically speaking,” said Pflager in an interview with the Seattle Times, “they [were] just modems...that have no smarts at all.”
 The new SCADA system, scheduled for completion in late October 1999, will change all of that. System testing was completed on June 30 of this year and a successful simulation of the system was run to catch and correct any defects. The new system passed all compliance tests with flying colors.
 Seattle Public Utilities will be adding two more, remote telemetry sites for the combined sewer overflow stations soon. These sites will also use the same Allen-Bradley/ProSoft solution as the main project.


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