However, there is no reasonable reason to ignore this subject with regard to interface devices. On the contrary, if the route between the field device and the control system is also monitored, this produces a continuous stream of error documentation and thus efficient asset management.
The first approaches in cable diagnostics were made as early as the mid-sixties. The NA01 describes the first diagnostics from the interface device with the so-called “NAMUR characteristics”. This tool was also used in the seventies for the 4...20 mA analog signal on the basis of NE06. Another advance was made with the introduction of the Hart protocol in 1986.
However, this technology has as yet mainly been used for communication with the field device, i.e. for parameterisation tasks. The potential of this technology is therefore far from fully exploited. At the same time the issue of diagnostics is becoming increasingly more important for plant operators who nowadays often face a dilemma.
On the one hand, they have to achieve higher levels of productivity with constantly improving processes and methods. This requires the even closer adherence to measurement and control parameters. On the other hand, the demand for increased safety continues to grow...
Dipl.-Ing. Jörg Tauert
is product specialist for interface technology
in the product marketing department of
Hans Turck GmbH & Co. KG
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