SCADA lives
A favorable regulatory climate and improving technology pump new life into wireless monitoring and control.
Regulatory changes and technical advances can be expected to breathe new life into the arena of supervisory control and data acquisition (SCADA) equipment in the coming decade. At the same time, more emphasis will be placed on increasing productivity and reducing overhead by moving from copper- and fiber-based SCADA systems to wireless over licensed and unlicensed spectrum.
Adding fixed to mobile Although SCADA communications are generally fixed, and not within the realm of “mobile” radio technology, the installation, maintenance and supervision of such systems often falls into the bailiwick of the industrial communications systems manager. SCADA devices are used in security, environmental control and industrial applications, such as oil and gas production and distribution. Utilities use SCADA on radio frequencies to automatically monitor power plants, pipelines and distribution centers. One example would be to display the status of lower-voltage substations. SCADA applications reduce personnel needs for onsite monitoring, reduce power consumption for control devices and provide faster detection and correction of errors in systems they monitor.
A particularly informative SCADA education track is featured each year at the ENTELEC energy communications conference. This year’s conference takes place in Dallas later this month. (See the box on the opposite page.)
SCADA systems consist of four major parts: 1) a human machine interface (HMI), which is a computer program that requests remote sensor data; 2) the communications infrastructure, wired or wireless; 3) remote terminal devices (RTUs) that provide input/output capabilities; and 4) an application for receiving and displaying information from the polled sensors that may also be used to send commands, such as “close valve 12,” to a remote site.
From copper to the air Metric Systems President William Brown, writing in the January issue of MRT’s sister publication, RF Design, noted that there is an ongoing transition from copper-based to wireless-based control systems that may come to account for 20% to 50% of private networking. Brown portended that wireless will become the most reliable and least expensive choice for industrial automation, with full duplex throughputs of data becoming cost-equivalent to 9600-baud narrowband copper and fiber systems. According to Brown, four change agents affect industrial automation: 1) a greater comfort factor and knowledge base among information technology managers; 2) “aggressive rejection of proprietary products or communications schemes”; 3) the advent of more open architecture systems; and 4) FCC actions to supply more bandwidth.
Regulatory climate In the latter case, utility and energy communications received a boost in January when the FCC announced it will resume licensing for multiple address systems (MAS) in the 900MHz bands. MAS historically has been used for alarm, control, polling and status reporting communications in the power, petroleum, security and paging industries. The commission created a three-pool licensing approach for the 932/941MHz MAS band. One pool of 20 paired channels will be auctioned. However, one pool of five paired channels will be licensed site by site to government and public safety entities, and one pool of 15 paired channels will be licensed site by site to public safety and private systems users such as utilities, pipelines and other infrastructure industries. The FCC had been examining a new licensing approach since early in 1997, and then had frozen licensing in July of last year. Therefore, the long-awaited release of the spectrum was heralded by industry trade groups.
The Public Safety and Private Wireless (PS&PW) Division of the FCC’s Wireless Telecommunication Bureau has also been a friend to SCADA users in recent months. In January, the division allowed Tenneco Communications to convert developmental licenses for 10kHz “sliver” channels in the 30MHz band into regular five-year licenses. The licenses are used to provide gas-metering SCADA for El Paso’s Tennessee Gas Pipeline System. Channels in the higher-frequency MAS band were either unavailable or ill-suited to propagation over the terrain, and using 450MHz-470MHz (if available) would have been on a secondary basis and had the potential for interference. Tenneco opted for the 30MHz approach, and the FCC acceded to the request.
In October, in adjudicating an interference dispute, the PS&PW Division supported a Vermont water district’s assertion of the primacy of its SCADA monitoring use of 452MHz over the same-band presence of an improperly licensed private station. A footnote to this case is the position taken by the Industrial Telecommunications Association (ITA) in its role of resolving interference complaints in cooperation with the FCC’s Compliance and Information Bureau (now the Enforcement Bureau). ITA held that SCADA transmissions of continuous data without a monitoring capability place those SCADA operations on a secondary basis. The private station was shut down by the FCC because it was operating on an improper license transfer, but nothing in the PS&PW Division’s decision contradicted the ITA position on status.
New approaches The SCADA marketplace is becoming both a land of opportunity and more tightly focused. More than 400 suppliers deal with some aspect of SCADA software or instrumentation. At the same time, established firms are recombining into stronger entities, such as the 1997 incorporation of Johnson Data Telemetry into Dataradio. The merger was rechristened as Dataradio COR (for Connectivity Over Radio) in 1999 and led to the release of RF modules the size of business cards that include surface acoustic wave (SAW) filter designs.
Suppliers are ramping up new software designs targeted at dispatch centers and working on ways to incorporate SCADA data into larger corporate information technology (IT) networks. Internet protocol (IP) over wireless will therefore continue to be a hot topic. Emphasis will be placed on making SCADA data available to these networks in real time. And, like all IT systems, protection from interference and security for SCADA communications will be primary considerations.
SCADA users are finding a shrinking upgrade cycle as well. Duane Clementson, vice president of operations for UTSI International, Friendswood, TX, has estimated that the upgrade cycle has fallen from 15 to three years. Improvements in wireless technology, opportunities for new bandwidth and information systems convergence are breathing new life into SCADA.
As of press time, the following papers on SCADA systems were scheduled to be presented at the ENTELEC energy telecommunications conference at the Dallas Convention Center, Dallas, on March 19-22. For further information, see the ENTELEC Web site at www.entelec.org.
* “The challenge of SCADA: The application of information technology in pipeline systems”
Presenters: Martin W. Mans and Herwig S. Mlaker, PLE Germany
* “SCADA outsourcing-A business case”
Presenter: Gerald E. Snow, UTSI International
* “What Drives a SCADA system upgrade?”
Presenter: Al Senftleber, Senftleber & Associates
* “Implementation of the Web server for process control”
Presenters: Irwan T. Tantu and Ken Booth
* “TECO Peoples Gas SCADA replacement project”
Presenters: Bill Cooper, Matrikon Consulting, and Todd Weidley, TECO Peoples Gas
* “Designing a cost-effective SCADA system”
Presenters: Janice Hungerford and Danetta York, ProSoft Technology
* “Success of a self-built SCADA system: Walking away from the traditional approach”
Presenter: Glenn Stoner, Colorado Springs Utilities
* “Transform your SCADA department from a cost center into a profit center”
Presenter: Duane P. Clementson, UTSI International
* “Wireless SCADA system design considerations”
Presenter: Ernest J. Zingleman, Dataradio COR
* “Integrating security and access control for remote locations with the SCADA host”
Steve Nibblelink, Honeywell
* “Qualifying SCADA personnel for OPS Rule 49 CFR Part 195”
Presenter: Duane P. Clementson, UTSI International
* “Encryption provides low-cost SCADA operating security”
Presenters: John A. Kinast and William F. Rush Jr., Institute of Gas Technology