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Automation Technologies 2/2014

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Automation Technologies 2/2014

Sensors and Measurement

Sensors and Measurement On the requirements for newgeneration process instruments Jens Baar The requirements of today’s developments are characterized by “miniaturisation”, “intuitive operation”, “compatibility” or “price-performance optimisation”. Buzzwords with positive implications for the customer which have long been discussed within consumer electronics and communications technology. With products for industrial processes, it is therefore often possible to find parallels. Read more about a resistance thermometer as a trendsetter for the process industry. As against the rapid pace of development in the field of “consumer electronics”, the process and machine-building industries are rather sluggish with innovation. At first, this may sound negative, but this is not the case. In the face of the complex requirements, and also with an eye on the existing systems and installations which are still working properly, both industries put greater emphasis on proven technology. This is particularly true for devices that are used in large quantities in production or which do not need be seen as high-end. The difficulty in the conceptual design and the development of new products for these industries lies in amalgamating “requirements of the 21st century”, mentioned initially, with the sector-specific characteristics: Safety, accuracy, but also backward compatibility — a very important aspect that, since it is self-evident, is rarely mentioned explicitly. In addi- back to current issue Author: Jens Baar, Product Manager, Temperature Transmitters, Electrical Temperature Measurement, Wika Alexander Wiegand SE & Co. KG, Klingenberg/Germany

Sensors and Measurement next page tion, the integration of approval-related parameters must be considered. Without the appropriate certificates or market-specific approvals, the door to these specific industry sectors remains closed. Example of new development: resistance thermometer The change process that the process and the machine-building industries have put into place in recent years with respect to equipment for plant technology can be understood with the example of the new TR33/34 resistance thermometer from Wika — a compact instrument with an integrated digital transmitter. Keyword ‚standardisation‘: In the process industry, the standard 4-20 mA signal, with which the resistance thermometer works, is now widely used. This acceptance also leads to a rethink in machine building, where for historical reasons the 0-10V output plays a greater role. The 4-20 mA signal with its various advantages, such as two-wire connection and power supply for the end device over the signal circuit (loop-powered), is becoming more and more accepted here. Compact and highly functional As with consumer electronics, the miniaturisation of devices or components must not, under any circumstances, be at the expense of performance or functionality. What is wanted is, in fact, the opposite. To stick with the example of the TR33/34: A miniature thermometer with a 19 mm housing, integrated sensor and a 4-20 mA output would still, on its own, not constitute sufficient basis for being widely used. For this reason, some innovations have been incorporated in the instrument, such as an EMC concept with two separate printed circuit boards. The main board, containing the measurement circuit, the Ex-relevant components and the microprocessor, is separate from an EMC board. The thermometer 01 The resistance thermometers of the series TR33/34 are used as universal thermometers for the measurement of liquid and gaseous media in the range of -50 ... +250 °C therefore has the best possible protection against electromagnetic interference. Far more important for the scope of use is another characteristic of the PCB design: In spite of the minimum space, the electronic components were able to be arranged in an explosion-protection compliant way. Thus, the TR34 features an ATEX approval. Intuitive operation In order to fully exploit the benefits of an integrated digital transmitter, dedicated configuration software is required. With the requirements associated with this, the process industry is also orientating itself to an increasing extent to the consumer electronics model. Programs such as “Wikasoft_TT” should be available to download (at all times in the latest release) and working with them should be made as easy as possible through the appealing design of the user interface and their intuitive operation. About Company: Wika Alexander Wiegand SE & Co. KG Headquarters: Klingenberg, Germany Turnover: 750 Mio. Euro (Wika Group) Employees: 7.900 (Wika Group) Products: pressure, temperature and level measurement technology AUTOMATION TECHNOLOGIES 2/2014

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