CONTINUING WITH the past theme of what is required for a successful digital network installation; this month we will discuss the critical link in the chain, the installation contractor. Unfortunately there is not yet a certification or similar available to ensure a minimum degree of competence for the trades commonly used to do this work. The good news however is that with the increased deployment of Ethernet in all sorts of environments, including many newer homes these trades people are gaining experience. (Of course in some cases, another way of saying experience is “I’ve made that mistake before.”) The trick is to not be the one providing the experience.
The flavors of Industrial Ethernet
Typical items that are different for fieldbus systems include the need for terminators, special termination assemblies, special cable or connection of the cable in a different way than has been done in the past, as well as in some cases requirements on spacing between the digital network cable and other cables in the field junction box and associated cable trays and to a lesser extent conduit runs.
Fortunately, at least in the case of the Fieldbus Foundation a number of facilities around the world have been identified to provide a variety of training courses on this technology, including: 3 in North America and others in Singapore, Japan, Northern Europe, and China. The End User Council in Australia also provides similar training.
Another good place to start your familiarization of a new technology is the web site of the appropriate supporting organisation for their technical overview guide since this document summarizes the unique attributes of the fieldbus in question.
The final component to a successful installation is the knowledge on how to use the tools and diagnostic equipment that verifies the work has been done correctly. Fortunately, continuity checks and similar exercises remain unchanged because a wire is still a wire. What does change however is the need to determine additional parameters beyond Resistivity and Impedance, for example capacitance in Profibus PA and Foundation Fieldbus H1.
The good news here is that there are a number of simple tools on the market to assist in verifying network integrity and additional products just coming out of their respective “skunk works” that will be released for sale by several manufacturers over the next 6 months.
Next column we will provide a short “tutorial” about Function Blocks and how they are used by Fieldbus.
As always, your comments and suggestions on the above as well as for potential future topics of discussion are encouraged. Please contact me at the information below.
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