-------------------------Monitor------------------------ The Newsletter for PC-Based Data Acquisition and Control Issue 91 www.windmill.co.uk February 2006 --------------------ISSN 1472-0221---------------------- Hello and thanks for subscribing to Monitor. This month we launch a new feature: a round-up of the top data aquisition and control news stories of the past few weeks. How do I judge "top", well actually it's just the few that I liked the best - I hope you like them too. Should you wish to cancel your subscription to Monitor you can do so at http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill Notes: Monitoring Gas Sensors with a Strain Gauge Measurement Package * DAQ News Roundup * Data Acquisition and Control Exhibitions ________________________________________________________ ________________________________________________________ Windmill Notes: Monitoring Gas Sensors with a Strain Gauge Measurement Package ________________________________________________________ Gas sensors are typically made as heated wire elements which change in resistance as the target gas concentration changes. They can detect specific gases such as carbon dioxide or a group such as inflammable gases. Because they are monitored using a bridge circuit to detect changes in resistance, the Windmill 751 strain gauge package is well suited for logging from one or more gas sensors. This plugs into the PC's USB port. Having a sensing element and a reference element, they form half of a wheatstone bridge circuit. The other half is formed by the boxed bridge-inputs unit (the 594) which is included in the package. This has several configuration options and you need to choose the half bridge input. Power requirements for gas sensors are different to those for strain gauges. Typically they require 3 V DC at up to 0.5 A in order to heat and maintain the element at temperature. This means that an external supply will be required, since the USB is not able to supply that level of power. For a couple of gas sensors we used a voltage selectable plug-top supply capable of 1.25 A at 3 V. The polarity of the gas sensor connection is important, so make sure the positive output of the sensor goes to the +IN input on the 594, and the negative output of the sensor goes to the -IN input on the 594, otherwise there will be no response to a change in gas concentration. The power is supplied to the sensor through the +EX and -EX connections of the 594, and the external power supply is connected through the +POWER INPUT and -POWER INPUT connections. The -EX may also be connecetd to the 0 V connection so that the negative supply of the bridge circuit is connected to the 594 Common. The bridge circuit is suitable for monitoring changes in gas concentration, but a reference level is required. Typically this will be the open to atmosphere concentration. Windmill software is used to setup the measurement channels for half-bridge strain gauge monitoring. In the Windmill ConfIML program you will need to specify the use of a 594 connection unit, and in Windmill SetupIML, the channels in use for gas sensors are specified as half-bridge configuration. At the channel level in SetupIML the zero level can be set to balance the bridge at atmospheric concentrations. It is more convenient however to use the SGzero program (available free with the 751 strain gauge package) since you can use this to rebalance the bridge at any time. Further Reading =============== Windmill 751-SG - Strain Monitoring and Control https://www.windmillsoft.com/daqshop/strain-measurement.html Computerised Strain Measurements http://www.windmill.co.uk/strain.html ________________________________________________________ ________________________________________________________ DAQ News Roundup ________________________________________________________ Welcome to our roundup of the latest findings in data acquisition and control. If you would like to receive news updates as they happen then grab our RSS newsfeed at https://www.windmillsoft.com/monitor.xml. Read http://www.windmill.co.uk/newsfeed.html for information how. Robot Moved by a Slime Mould's Fears A bright yellow slime mould that has been put in charge of a scrabbling, six-legged robot. The Physarum polycephalum slime, which naturally shies away from light, controls the robot's movement so that it too keeps out of light and seeks out dark places in which to hide itself. As the slime tried to get away from light its movement was sensed by circuit and used to control one of the robot's six legs. The robot then scrabbled away from bright lights as a mechanical embodiment of the mould. Eventually, this type of control could be incorporated into the bot itself rather than used remotely. Source: NewScientist.com news service http://www.newscientist.com/channel/mech-tech/dn8718.html Electronic Nose could Spell the end of Landfill Pongs Scientists at the University of Manchester have invented a new device which remotely monitors bad odours and methane gases at waste landfill and water treatment sites. The device, which works like an electronic nose, could be the solution many communities and waste management companies, are searching for. Currently there is no other instrumentation sensitive enough to monitor low concentrations of odours and gases on these sites. Gases and odours are analysed manually using handheld detectors and by panels of volunteers asked to smell samples of air. Source: The University of Manchester http://www.manchester.ac.uk/discover/news/ Call for International Standards to Shape the "Digital Home" Household connectivity is growing rapidly with more and more electronic devices and networks within the home distributing and using digital information. Given the various technologies involved, international standards that enable interoperability and security are seen as key to bringing value and versatility to consumers, making possible the use of diverse products, services and sources, and therefore accelerating market development. Source: The International Electrotechnical Commission (IEC) http://www.iec.ch/news_centre/release/nr2006/nr0306.htm New Design for Transistors Powered by Single Electrons Scientists have demonstrated the first reproducible, controllable silicon transistors that are turned on and off by the motion of individual electrons. The transistors are based on the principle that as device sizes shrink to the nanometer range, the amount of energy required to move a single electron increases significantly. This makes it possible to control individual electron motion and current flow by manipulating the voltage applied to barriers, or gates, in the electrical circuit. Source: National Institute of Standards and Technology https://www.nist.gov/public_affairs/techbeat/ ________________________________________________________ ________________________________________________________ Data Acquisition Exhibitions and Conferences ________________________________________________________ Continuing the quarterly list of exhibitions around the world in the data acquisition and control field Otomasyon Istanbul Turkey 16-19 March Industrial automation fair. http://www.bilesim.com.tr/ National Industrial Automation Show and Conference Chicago Illinois USA 20-23 March The event for automation and control engineers, manufacturing managers and system integrators from across the USA. http://www.manufacturingweek.com/ Automaticon Warsaw Poland 21-24 March International fair for measurement and control. http://www.automaticon.pl/ IEEE Instrumentation and Measurement Technology Conference Sorrento Italy 24-27 April Tutorials in instrumentation and measurement. http://ewh.ieee.org/soc/im/imtc/index.html Hannova Messe: Interkama Hannover Germany 24-28 April Trade fair for process automation. From overall system planning and control systems to field devices and components, plus all the services needed for the operation of industrial plants. http://www.hannovermesse.de/ Sensor+Test 2006 Nuremberg Germany 30 May - 1 June International Trade Fair for sensorics, measuring and testing technologies. http://www.sensor-test.de/main/dpgh71tn/page.html Sensors Expo & Conference Rosemont Illinois USA 5-7 June Exclusively focuses on sensors and sensor-integrated systems. http://www.sensorsexpo.com/sensors2006/v42/index.cvn COMADEM 2006 Lulea, SWEDEN 12-15 June International congress and exhibition on condition monitoring and diagnostic engineering management http://www.comadem2006.ltu.se/ ________________________________________________________ ________________________________________________________ * Copyright Windmill Software Ltd * Reprinting permitted with this notice included * For more articles see http://www.windmill.co.uk We are happy for you to copy and distribute this newsletter, and use extracts from it on your own web site or publication, providing the above notice is included and a link back to our website is in place. An archive of previous issues is at http://www.windmill.co.uk/newsletter.html and an index of articles at http://www.windmill.co.uk/newsletter.html Windmill Software Ltd, PO Box 58, North District Office, Manchester, M8 8QR, UK Telephone: +44 (0)161 833 2782 Facsimile: +44 (0)161 833 2190 E-mail: [email protected] http://www.windmill.co.uk/ https://www.windmillsoft.com/
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