Interoperability and Backward Compatibility
We Energies' Todd Gordon notes, "Valley Power Plant has been using HART smart instrumentation since the late 1980s. The transmitter loop test function has been used for troubleshooting and insurance compliance testing of the boiler trip functions. HART smart valve positioners have been used since 1999, and they have provided valuable diagnostic capabilities that have allowed us to troubleshoot problems while the valves are in operation. It also helps to pinpoint problems before mechanics start taking valves apart. A leaking valve diaphragm that has been identified with diagnostics can be replaced without removing the valve, which saves time and money. We have found numerous problems before they affected plant operations."
Gordon adds, "Other power plants in our company have adopted HART technology over the years. The older Oak Creek Power Plant added an AMS on-line system when they installed wireless transmitters on their feedwater heaters for performance monitoring. Pleasant Prairie started using digital valve controllers in 2003, has an online AMS system and recently added some WirelessHART transmitters to their systems."
Gordon says HART interoperability is transparent. "Two new plants were built in the last few years by two different contractors (Washington Group & Bechtel)," he says, "and both plants came standard with on-line HART technology to communicate with the HART smart instrumentation in the plant."
Save Time and Money on Calibration and Diagnostics
Galata's Marse says, "Our plant is using AMS Intelligent Device Manager and HART to monitor diagnostic alerts and for calibration management to reduce maintenance time and maintain calibration compliance. The central system links real-time HART data and instrument documentation in a single system which provides a single source for the I/E technician."
Without the ability to enter calibration data directly into the asset management system, the data that is collected about the actual condition of the instruments other than the HART diagnostic data is suspect.
Jim Shields, product manager for calibrators for Fluke, points out, "Several surveys have shown that paper-and-pencil documentation produces and perpetuates errors. Further, as maintenance and operations departments have less and less time and fewer employees, much of the data collected on clipboards will just be filed and not used. In addition, entering this manually collected data into CMMS systems is also a manual operation, taking time, costing money and usually far down the list of things that must be done to keep the plant operating and producing revenue. That's why the new Fluke 754 Documenting Calibrator has HART connectivity. Both sets of data can be documented and uploaded directly to the CMMS."
Just how much money can you save using HART diagnostics? "On-line diagnostics provided by the HART instruments does something more than preventive maintenance," says József Bartók, automation engineer at MOL Danube Refinery in Hungary, adding that this "ensures the stable operation of the system and increases the precision of control." Beyond fixing what breaks or keeping the plant running, a reliable, stable operation contributes to bottom-line profitability.
On-line and off, HART has proved its mettle according to Bartók.
In one case, the head pressure control was slow on one unit leading to the assumption that a valve was stuck and in need of removal and repair. But technicians with on-line diagnostic tools used HART-supplied data to interrogate the valve and find current-to-pneumatic damage only in the intelligent positioner–not the whole valve.
Operators put the valve in manual, and the fix took a half hour of instrumentation work. This saved the plant at least two days of unscheduled downtime, or approximately €637,000 ($897,790 USD).
Savings, increased throughput, reduced downtime—spell it any way you want. You already have all the data you need to gain savings like MOL did—in your HART instruments.
Wired or Wireless—HART's the Same
Engineers and operators who are familiar with how to connect HART to their control and asset management systems are finding IEC62591-WirelessHART a breeze to add to their systems. Each WirelessHART transmitter behaves exactly like its wired counterpart. This is thanks to the interoperability and interchangeability specifications designed into the HART and WirelessHART specification from the beginning. The biggest difference between the two is that there are no wires.
We Energies added an asset management system (Emerson's AMS Suite) and WirelessHART sensors, according to Gordon, "when they installed wireless transmitters on their feedwater heaters for performance monitoring." The AMS Suite has what is called a "snap-in" module that performs network management and device site selection for wireless instruments and final devices.
No matter what vendor's brand of HART or WirelessHART devices you use, you can be assured of a simple and easy way to improve your asset management—with tools you already have. So get connected with HART right now!