DTI study cites P-NET fieldbus flowmeter with PID control

Citation

(1999), "DTI study cites P-NET fieldbus flowmeter with PID control", Sensor Review, Vol. 19 No. 1. https://doi.org/10.1108/sr.1999.08719aab.002

DTI study cites P-NET fieldbus flowmeter with PID control

DTI study cites P-NET fieldbus flowmeter with PID control

Keywords Fieldbus, Flow, Sensor fusion

In a recently issued DTI sponsored study ­ The Impact of Fieldbus and Sensor Fusion on Flow Measurement[1], one of the main conclusions reached was that the use of fieldbus technology over traditional designs yielded overall cost savings in the order of 25 per cent. Owing to the fact that fieldbus is about connecting many devices to a single communicating cable, one of the obvious reasons for this is a significant reduction in wiring. However, it is also pointed out that associated advantages of a reduction in design, installation and commissioning time, together with an increase in reliability, leading to a reduction in preventive maintenance, are all contributory factors in reducing the lifetime costs of such a control system. Since fieldbus technology relates to distributing "intelligence" around a plant or process, it means that not only fieldbus sensors, actuators and transmitters provide a basic measurement, in the form of say a pressure, temperature or flow rate, but these fieldbus nodes can provide remote control, configuration, and analytical data on the state of such a device. A further consideration studied was that of "sensor fusion". Basically, this means that if more than one prime measurement can be obtained from a single sensor module, these can be integrated to produce a new derived measurement. For example, if a flow meter module can measure both flow rate and temperature, then you will be able to obtain not only both these individual readings, but also the fused result in the form of temperature compensated flow rate. Taking this a little further, integrating either flow rate or temperature compensated flow rate over time will yield volume or temperature compensated volume.

Therefore, making a measurement device intelligent, and providing it with a fieldbus interface, will enable such an instrument to be utilised as an autonomous measurement and/or control function block, within a larger process automation system.

The above mentioned study cited the PD340 as such an intelligent flow metering device from PROCES-DATA, which offers a P-NET fieldbus interface (BS EN 50170 Vol. 1), not only for its ability to exhibit the sensor fusion techniques being advocated, but also as offering rather unique additional functions such as in-built PID and batch control. Such facilities epitomise the aims of the study, which are to encourage manufacturers and users to fully utilise the advantages of fieldbus technology, together with sensor fusion and sensor validation (SEVA) techniques, in order to provide efficient, reliable and cost effective instrumentation, to meet the never ending struggle for competitiveness.

For further information contact International P-NET User Organization ApS, PO Box 192, Wallingford, Oxon OX10 6XU, UK. Tel: +44 (0)1491 828 200; Fax: +44 (0)1491 828 201; E-mail: pnet@easynet.co.uk; Web: http://www.p-net.dk

Reference

1. 1.

   Department of Trade and Industry, NMS Programme for Flow Measurement, Project OR9A Technical Awareness Studies, The Impact of Fieldbus and Sensor Fusion on Flow Measurement, Sira Test & Certification Ltd, June 1998.