[...] when different devices operate do not operate in the same way, the technicians will not have learned to perform the right keystrokes automatically, and they will lose precious time searching for functions and may even make mistakes. [...] it is important device management software and tools work consistently for all devices making use intuitive and reducing mistakes, particularly under stress. The technician cannot routinely pay attention to which kind of device and the task at the same time. [...] all devices should work the same way, for instance to apply an edited value, how to print, how to get help, and how to pan/ zoom on the graphs and charts, and the like.
Fdt + EddL = FdI Upon standardizing interfaces, the guarantee is the consistency of data, documentation, and conﬁguration D By Nicholas Sheble evice integration allows each instru- and maintenance tools without constraints of ment’s data presentation to be famil- communication or platform compatibility. iar and informative to the operator. No One needs not replace existing installed de- doubts, no searching, and no confusion are part vices. FDT technology incorporates existing de- of the man-machine information exchange. vice models. Regardless of the model, the vendor, the age of FDT supports HART, Proﬁbus, Foundation the device, the communication protocol at work, Fieldbus, DeviceNet, Interbus, AS-Interface, and or the complexity of the measurement, the output ProﬁNet. Importantly, FDT is an international display will be consistent graphically and in con- standard, IEC 62453. tent when successful device integration is at work. The second technology is Electronic Device With the advent of and commercial adoption Description Language (EDDL), and it is associ- of digital ﬁeldbuses in the 1990s, two techniques ated with process industry organizations like the of device integration came to the fore and are Fieldbus Foundation, Emerson Process Manage- popular still—FDT and EDDL. ment, the HART Communication Foundation, Field Device Technology (FDT) is traditionally Proﬁbus International, and the OPC Foundation. associated with users and vendors of the discrete It, too, is independent of communications proto- persuasion like ABB, Endress+Hauser, Invensys, col and can thus integrate data from HART, Wire- Metso, and Siemens. lessHART, Foundation ﬁeldbus, and Proﬁbus de- Fast Forward However, not solely vices in the same tool. l A technician cannot pay attention to the so. FDT is not a facto- EDDL is not software, and therefore has no kind of device, so all devices must work ry-automation-only tightly coupled procedure calls that could fail. If and display in the same mode. technology. the EDDL declaration is faulty, the host will re- l FDI incorporates the best aspects of the To be sure, FDT is port this just like a web browser reports there is EDDL and FDT solutions and eliminates platform independent an error on an HTML page. their redundancies. granting the freedom Moreover, since EDDL is not software, mali- l Release of the ﬁnal, functional FDI to choose best-in- cious code cannot latch on. It, too, is an interna- speciﬁcation will be the middle of 2010. breed instruments tional standard, IEC 61804-3. 20 INTECH SEPTEMBER 2009 WWW.ISA.ORG system integration Complements, redundancies Over the years, protocols and processes have con- “the FDi project is a key priority for the global au- verged. The lines between discrete, factory, batch, and process control have blurred on the one hand
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