-------------------------Monitor------------------------ The Newsletter for PC-Based Data Acquisition and Control Issue 134 www.windmill.co.uk September 2009 --------------------ISSN 1472-0221---------------------- Welcome to Monitor, the data acquisition newsletter. I hope you find it useful, but should you wish to remove yourself from our mailing list please go to http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill News: Data Acquisition and Control Glossary * Excel Corner: Quick Formula Help * DAQ News Roundup ________________________________________________________ ________________________________________________________ Data Acquisition and Control Glossary ________________________________________________________ We've updated our glossary of terms relating to data acquisition and control. Thanks for pointing out words we had missed. For the full glossary go to http://www.windmill.co.uk/glossary.html. Alias A false picture of a high frequency waveform that has been sampled at too low a rate. Acquisition Time In analogue-to-digital conversion, the time taken for the sample and hold circuit to settle to the input voltage. Also known as Sample and Hold Acquisition Time. (Sample and hold circuits are not used with integrating converters.) Bipolar A signal that ranges between a negative and a positive value, -10 V to +10 V for example. Bus Transfers data from the data acquisition device to the computer. Examples include Universal Serial Bus, Modbus and General Purpose Interface Bus. Network communications like Ethernet are not generally regarded as buses. Celcius A temperature scale where the freezing point of water is 0 degrees and the boiling point 100 degrees. Symbol is C. Conversion Time The time taken to convert an analogue signal to a digital signal. The sample and hold circuit of an analogue-to-digital converter freezes an otherwise varying analogue voltage at the moment the sample is required. This voltage is held constant whilst the A-D converter digitises it. External Trigger A trigger is something that causes data acquisition to start. An external trigger lets you synchronise data acquisition with something happening in the real world. For example when you switch on a machine or when a signal crosses a threshold. I2C A 2-wire serial bus developed by Philips. Integrating A-D Converter An integrating A-D converter averages the input signal over a length of time. This is useful when the signal to be measured fluctuates slowly. By averaging the signal the converter helps reduce unwanted signal contamination (noise). Farenheit A temperature scale where the freezing point of water is 32 degrees and the boiling point 212 degrees. Superceded for scientific purposes by Celsius. Symbol is F. Kelvin A temperature scale which is one of the seven base units in the International System of Units (SI). In theory, the zero point on the Kelvin scale is the lowest possible temperature where there is no heat energy: -273.15 oC. The freezing point of water is 273.15 Kelvins and the boiling point is 373.15 K. Symbol is K. Least Significant Bit, LSB In a binary number, the 1 or 0 furthest to the right. Most Significant Bit, MSB In a binary number, the 1 or 0 furthest to the left. Negative Edge Trigger Data acquisition starts when an input signal changes from a high to a low state. Positive Edge Trigger Data acquisition starts when an input signal changes from a low to a high state. More definitions are at http://www.windmill.co.uk/glossary.html _______________________________________________________ ________________________________________________________ Excel Corner: Quick Help on Formulae ________________________________________________________ When you know the name of a formula but can't remember the arguments it takes. 1. Enter the name of the formula in a cell. 2. Press Ctrl A. The Function Wizard appears letting you enter values and creating the formula for you. Alternatively, if you just want to view the arguments in the formula. 1. Enter the name of the formula in a cell 2. Press Ctrl+Shift+A. You will see all the arguments for that function- For more tips on using Excel see http://www.windmill.co.uk/excel/ http://www.windmill.co.uk/excel/excel-charting.html ________________________________________________________ ________________________________________________________ ________________________________________________________ DAQ News Roundup ________________________________________________________ Welcome to our roundup of the data acquisition and control news. If you would like to receive more timely DAQ news updates then grab our RSS newsfeed at https://www.windmillsoft.com/monitor.xml. Read http://www.windmill.co.uk/newsfeed.php for notes on how to display the live news on your own web site. Lower-Cost Solar Cells to Be Printed Like Newspaper Solar cells could soon be produced more cheaply using nanoparticle "inks" that allow them to be printed like newspaper or painted onto the sides of buildings or rooftops to absorb electricity-producing sunlight. Researchers are hoping to cut costs to one-tenth of their current price by replacing the standard manufacturing process for solar cells - gas-phase deposition in a vacuum chamber, which requires high temperatures and is relatively expensive. http://www.utexas.edu/ Prototype Detects and Measures Elusive Hazards NIST has demonstrated a relatively simple, inexpensive method for detecting and measuring elusive hazards such as concealed explosives and toxins, invisible spoilage in food or pesticides distributed in soil by wind and rain. Preliminary results indicate the method is sensitive enough to measure amounts of target materials that constitute as little as 0.0000002 percent of a sample. https://www.nist.gov/ Automotive Bus Driven Forward An industry consortium as been formed to drive further development and deployment of the Distributed Systems Interface (DSI) standard. DSI is the automotive industry's most widely adopted bus standard used to connect remotely placed sensors to the main airbag electronic control unit (ECU) in automobiles. http://www.dsiconsortium.org/news.php Electronic Nose Sniffs out Toxins Imagine a polka-dotted, postage stamp sized, sensor that can sniff out poisonous gases and toxins and show the results simply by changing colors. This is what is being developed by the National Institute of Environmental Health Sciences http://www.niehs.nih.gov/news/releases/2009/ Naval Sensor Market to Grow New analysis from Frost and Sullivan into the European naval sensors market, finds that the market earned revenues of over $28 million in 2008 and estimates this to reach $91 million in 2017. The market will likely grow by a further 35 per cent due to the rising importance for advanced technology and upgrades across European navies. http://tinyurl.com/n8w48w ________________________________________________________ ________________________________________________________ * 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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