JAN-FEB 2019

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INTECH JANUARY/FEBRUARY 2019 25 SYSTEM INTEGRATION manual adjustment by maintenance personnel. What was missing from this environment was any information about the instrument itself, or about secondary process variables, such as the tempera- ture from a pH sensor. HART emerges In the early 1980s, instrument vendors realized the potential benefits of digital technology in instruments. There was a wealth of useful data contained in an instrument, including other mea- sured process variables, device configuration, alarm limits, operating time, operating condi- tions, diagnostic information, and a broad range of device health data. Obtaining this data from an instrument helps optimize the use of the device, and ultimately im- proves process performance, and HART communi- cations emerged as one of the first ways to access this stranded data to make an instrument smart. HART digital technology allowed communi- cation with an analog instrument using a digital communication signal (Bell 202) transmitted over the same two wires as the analog output. This digital signal provided two-way communications between the instrument and a host without dis- rupting the output, allowing various pieces of data to be accessed. Using HART, personnel could talk to the instrument and perform configuration or diagnostics—all while it was making one or more real-time process measurements. At the same time, various companies were mak- ing progress in the development of other digi- tal technologies that would be transmitted over dedicated communication highways, each offer- ing specific benefits. Various Fieldbus technolo- gies emerged—including EtherNet/IP, F OUNDATION Fieldbus, Profibus, and Modbus—and today these compose the majority of new applications for fieldbus communications. In a similar fashion with respect to wireless digital communications, many technologies have been reduced to two clear leaders: ISA100 and WirelessHART. Digital technology expands The realization that instruments contained a vast amount of valuable data that could be bidirection- ally communicated between instruments and con- trol systems dramatically changed the way compa- nies operated a process and managed assets—and it drove the rapid expansion of digital technology in the industrial environment. There are very few in struments today that are not smart, at least to some extent. From the 1980s to 2000, digital com- munication technologies emerged in industrial markets, and today are providing significant benefits. Around the same time, office computer networks were evolv - ing. In 1989, the first prototype of the In - ternet was developed by Tim Berners-Lee and Robert Cailliau at CERN (the European Organization for Nuclear Research), eventu - ally leading to the implementation of the World Wide Web. With networked computers and the Internet, there came Internet-enabled coordi - nation and integration across the value chain, allowing suppliers to reach customers and business partners regardless of geography. This Internet-enabled integration has also al- lowed enhanced access to process data from the point of measurement all the way to the business system level and beyond. Not only can one see process data critical to the operation of a process, but one can also access this key asset information. As we move well into the second decade of this century, basic information technology has become more deeply embedded in industrial and consum- er products, allowing them to become part of the Internet of Things (IoT). In one lifetime, process control migrated from pneumatics to electrical analog, and then to sophisticated digital commu- nications extending out to the Internet. And most of today's smart instruments (figure 1) connect easily to digital communications systems, and in FAST FORWARD l Instrument transmitters gained intelligence through HART and other digital communications, then sensors became smart by integrating other types of digital technologies. l Smart instruments provide a wealth of data to host systems, including secondary process variables, calibration information, and diagnostics. l Smart sensors are the latest advancements in smart instruments, extending many smart transmitter benefits to the sensor level. Figure 1. Information can now be communicated bidirectionally between instruments and control systems, dramatically improving the way companies operate a process and manage assets. The Liqui- line transmitter is an example, communicating via EtherNet/IP, Mod- bus RS485, or TCP, PROFIBUS DP, and HART as well as a web server.

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