More than 30 million HART-enabled devices have been installed in process plants around the world. In fact, according to a recent market study released by ARC Advisory Group, there were 32 million installed HART devices, growing to 35 million in 2011, and the report projects growth to continue to 37.3 million devices in 2012. Many, if not most, of the instrumentation and final control element vendors in the world provide HART connectivity with their field devices. The HART protocol has become the standard for fieldbus communication in the world.
More and more, companies are seeing the benefit of doing more than being temporarily connected to the instrument or valve with HART communicator or PC communicator software for commissioning or calibration. They have seen that using HART to its fullest capabilities is an area of optimization, lowered cost and increased profitability.
Why Get Connected?
For the past 15 years, manufacturing theorists such as ARC Advisory Group have been talking about the benefits of implementing real-time decision making from the plant to the executive suite. Especially in the "high-cost" manufacturing countries, such as the United States, Canada and all of Western Europe, keeping plants open means showing increasing ROI to corporate planners. There are really few ways to do this. The two increasingly useful approaches are both about increasing productivity. The first is asset management. The second is advanced process optimization.
"Collaborative process automation and a continuous improvement plan utilizing performance feedback and the benefits associated with automation are the keys to automation's contribution to increasing manufacturing productivity, not the latest and the greatest technology," an ARC study reports.
Performance feedback is the key. Most plants have HART-enabled field instruments and final control elements. Simply connecting those instruments digitally to the control and computerized maintenance management systems (CMMS) provides much of the feedback that the ARC report is talking about.
Downtime is a key culprit. An ARC study done in 2007 reports that downtime still represents a significant percent of production lost. In oil refining, for example, downtime can be from 1% to 8%. In petrochemicals as a whole, downtime ranges from 2% to 5%, and in the food and pharmaceutical industries, downtime ranges from 1% to 10%.
It is easy to tie ROI into reducing downtime. So how do you reduce downtime? The answer has been clear for years: better and more predictive maintenance systems. But no maintenance system is any better than the sensors that feed information to it. If you are collecting information from those sensors about their sensor health and the processes they are monitoring by hand, the maintenance system is always behind. The quality of that hand-collected data taken off operator and technician clipboards is usually poor to unreadable, and says things like "didn't work—fixed it." State-of-the-art asset management systems need real-time data—real-time sensor readings and real-time diagnostics.
Evonik Degussa Specialty Chemicals Company in Shanghai, P. R. China, decided that HART technology would be used to connect field instruments to the distributed control system (DCS) as well as to the asset management and safety systems. There are more than 2000 HART-enabled instruments connected to the central control system, while the remote HART connection simultaneously feeds data to the integrated asset management and safety instrumented systems.
"As a direct result of this implementation," says Luc Sterck, Project Manager Instrumentation for Evonik, "we cut loop check time and costs by 25 percent, and daily troubleshooting of instruments are now mainly done from the safety and convenience of the control room."
The plant's predictive maintenance program is expected to reduce the total number of hours spent by maintenance teams. "We strongly believe," Sterck says, "that our plant's commitment to implement predictive device diagnostics on all HART instruments will bring comprehensive and pertinent operating information to key personnel and therefore assure better plant availability by predicting unexpected failures and avoiding associated downtimes."
The logic solvers of Evonik Degussa's plant use HART technology to connect with the sensors for loop check and safety instrumented function (SIF) interlock validation. Some of the logic solvers are used in complex online flammability calculations (SIL3).
Interoperability Gets YOU Connected!
You don't need to radically revise your plant's instrumentation schemes. Operators and maintenance techs already have all the data they need—right in their HART devices. Each HART device is designed to be interoperable—it starts in the HART specification, using EDD in every device, and then it is tested and registered by the HART Communication Foundation.
Since 2007, there has been a new way to get connected with HART. In 2010, the IEC approved IEC62591-WirelessHART, the first international open standard for wireless field devices. As data gathering needs expand, both for asset management and plant optimization, new devices and new functions can be added to the control system without the major expense and downtime of pulling new wires. And WirelessHART is designed to be backward-compatible and interoperable with wired HART devices.
"Because IEC 62591-WirelessHART is completely backward-compatible with any registered installed HART devices, using adapters such as the MACTek Bullet can easily get the diagnostic and secondary process variable information from existing HART transmitters without the cost, expense and time associated with new wiring. And, since the Bullet can support up to eight devices in a HART multidrop application, it makes the case for the adapter even more cost-effective," says Thomas Holmes, CEO of MACTek Corporation.
There has been an explosion of devices and systems that you can use for connectivity with HART devices. Almost all the major DCS vendors have now provided native HART digital data gateways directly into the control system. There are quite a few companies that make HART digital multiplexers that route the data to the control systems. Every tested and registered device is interoperable with any other, right out of the box.
As the chart in Figure 1 shows, there are numerous vendors for every type of HART device, including calibration and configuration devices. "Our company offers products for temporary use like our isHRT USB communication modem as well as solutions for permanent parameter acquisition, " says Tobias Thobaben of ifak system. "The modular isNetH@RT gateway provides parallel access to up to 40 HART lines, thus making it a real enabler for HART based asstet management solutions. Our free HART starter pack delivers real added value, allowing generic access to HART 5, 6, and 7 devices within FDT based applications," Thobaben continues, "and our isHRT USBeX intrinsically safe communication modem allows users to work on HART devices without shutdown or hot work permits."Thobaben's company is not alone in providing generic access. ProComSol has been a leader in providing PC-based software for commissioning, calibration and troubleshooting HART devices. CEO Jeffrey Dobos says, "our popular DevCom2000 Smart Device Communicator Software is now available for communicating with HART instrumentation from Mobile devices such as PDA's and Smartphones. Moreover, the name of the software has been updated from DevCom2000 PDA to DevCom2000 Mobile to reflect the manner in which mobile technology is changing the way people live and work. DevCom2000 Mobile uses the registered DD files from the HART Communication Foundation for complete access to all features of the instrument including Methods."
Like many mobile apps, DevCom2000 can be had on a try before you buy basis. "The enhancements in Rev 1.6 enable potential customers to try the DevCom2000 Mobile software for 10 days before deciding to purchase. They can experience the power of the DevCom2000 desktop version with the convenience of mobile technology," Dobos says.
Staying connected is simple. All HART devices are designed with both interoperability and interchangeability in mind. "Process industry users have very high expectations when it comes to interoperability," says Ron Helson, executive director of the HART Communication Foundation. "To them, interoperability is much more than devices sharing the same network infrastructure. Devices must integrate with the system in the same way without the need for multiple gateway types, special drivers and different system configuration methods. Similarly, devices should be commissioned, set up and calibrated the same way, and device diagnostics information should be consistent. HART, including WirelessHART technology, meets all these user requirements."
The standard HART command set and the vendor-specific commands return data values that are easily integrated into the control and asset management systems. In the control system, this additional digital data improves the ability for the operator to optimize the process. In the asset management system, the diagnostic data provides the information to predict maintenance requirements that techs and managers simply cannot get from clipboard-based rounds.
Getting connected is not rocket science. It will improve productivity, reduce maintenance and maintenance costs, and significantly reduce downtime. So what are you waiting for?