In years past, the city of Dallas, Texas, had been using laptop computers for instrument technician interface to a SCADA (Supervisory Control and Data Acquisition) system for maintaining their wastewater treatment plant. However, the city recently began using a system known as PocketBSI (Bristol System Interface), a new methodology that incorporates commercial PDA devices instead of laptops for system interface.
“With the PDA interface, we enjoy lower operating costs and more efficient field management with simplified portability,” said Steve Plummer, departmental technology analyst for the city of Dallas. “Access to the system is password-protected, so only authorized personnel can use it. We are still in the evaluation phase with a limited number of technicians issued PDA units, but virtually no installation problems have occurred. Because the system’s human interface is almost completely intuitive, learning time has been very short.”
Manufactured by Bristol Babcock, the PocketBSI maintains a versatile set of communication software “layers” to allow technicians to enter system parameters and configurations, view data, enter control and alarm information, and perform other operational procedures. It basically provides online, local access to the Bristol Network 3000 RTUs. Also, technicians can download application files and calibrate their transducers.
The Dallas system
The Dallas wastewater system has 47 RTUs with more than 13,000 input/output points. It pumps about 150 mgd and encompasses approximately 300 acres. With the emphasis on automation using modern equipment and methods, five technicians steadily maintain the system.
“This group is certainly a very busy bunch, but switching from laptops to PDAs will provide them greater flexibility,” said Plummer. “If more manufacturers come aboard with product and software development, we can extend the use of the PDA system to alleviate the need for various programmable devices now required for calibration of flowmeters.”
“We are evaluating a variety of flow devices that can utilize the PDA-based system for calibration while various vendors are working on driver software,” he added. “We are also examining the added flexibility of wireless connectivity where applicable.”
System flexibility shown by other applications
The PDA-based system used in the Dallas wastewater system developed to allow use in many industries.
For example, the FAA in Oklahoma City is evaluating use of the system to monitor terminal Doppler Radar from stations around the country. The new system is also at work in the oil industry. At least one major operator is using it at oil/gas production wells.
Another application in the energy arena is by TXU Gas to monitor action of various meters and analyzers being controlled by a laptop at the metering site. With about 400 RTUs in their network, the system can make a technician’s job much easier by using the convenient PDA units to monitor what’s happening to a networked device at the metering sites.
Especially desirable for most users is the fact that the manufacturer “does all the work” on the software. Users are offered the option of specifying, as a complete “plug-and-play” solution, a Compaq iPaq PDA with the PocketBSI software pre-installed, backed up on a flash card, and a USB serial cable compatible with all 9-pin Bristol communication cables. The user may also supply the PDA’s and load required software. The “premium” for a PDA with pre-installed software is small, which makes the complete package cost-effective.