-------------------------Monitor------------------------ The Newsletter for PC-Based Data Acquisition and Control Issue 145 www.windmill.co.uk August 2010 --------------------ISSN 1472-0221---------------------- Welcome to Monitor, the data acquisition and control newsletter. I hope you find it useful, but should you wish to remove yourself from our mailing list please go to https://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill Notes: Finding Data in Serial Messages * Excel Corner: Charting Tips * DAQ News Roundup ________________________________________________________ ________________________________________________________ Windmill Notes: Finding Data in Serial Messages ________________________________________________________ When you collect data from instruments that communicate over RS232, RS485 or Modbus, you need to extract the readings from the rest of the message. You need to "parse" the message to extract just the data items in which you are interested. Windmill has two divers to collect data from serial instruments. COMIML handles Modbus, RS485, RS422 and RS232 devices. More information is at www.windmillsoft.com LabIML is less versatile but is free to Monitor subscribers. It handles RS232 devices. Using Windmill you have three methods of locating your data item: 1. Search for specific characters in the message string. 2. Ignore characters until one of the ones you want appears. 3. Ignore a number of characters in the message string. At first glance methods one and two seem to do the same job, but there are differences. 1. When you search for characters the next action occurs AFTER the search term. When you ignore characters the next action occurs ON the specified character. So if you searched for a + sign you would not be able to extract it, but if you ignored all characters until the + sign you would. 2. A search will look for the entire string specified (eg "abc"), whilst ignoring characters will stop at any of the characters specified (eg "a" or "b" or "c"). ________________________________________________________ ________________________________________________________ Excel Corner: Charting Tips ________________________________________________________ We gave some tips for choosing an appropriate Excel chart type in issues 30 and 60 of Monitor, archived at https://www.windmill.co.uk/monitor30.html and https://www.windmill.co.uk/monitor60.html. The US Energy Information Administration's "Guidelines for Graphs" gives pointers on annotating and organising charts like these. For example. Layout and Scale 1. Avoid clutter that does not add necessary information for interpreting the graph (e.g., too many arrows, bubble boxes, grid lines, extra tick marks and other non-data features). 2. When possible, order values from highest to lowest or from lowest to highest if the data are not a time series. 3. Use the same scale whenever appropriate, so that the related graphs can be compared using a common scale. Dual axis graphs 1. Labelling is important when using a dual axis graph. Different scales are permitted on a dual axis graph. 2. Different chart types may be used for the variables, such as bars for volumes and lines for prices. 3. Use different colors for each variable and associate the variable's color with the axis label to help users determine which y-axis to use. 4. Stacked bar graphs and cumulative line graphs are not permitted in dual axis graphs. Three-dimensional graphs Avoid using three dimensional graphs when a two dimensional graph will present the same information. Further Reading:s http://www.eia.doe.gov/smg/Standards.html#S200225Supplement http://www.eia.doe.gov/smg/Standards.html#standard25 More Excel charting tips are at https://www.windmill.co.uk/excel/excel-charting.html https://www.windmill.co.uk/monitor60.html#Excel https://www.windmill.co.uk/monitor30.html#Excel If you have a question about using Excel for data acquisition, please get in touch. Fill in the form at https://www.windmill.co.uk/excel/. ________________________________________________________ ________________________________________________________ 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 https://www.windmill.co.uk/newsfeed.php for notes on how to display the live news on your own web site. Virus targets Siemens control systems Dubbed Stuxnet and spread by devices plugged into USB computer ports, a new virus targets process control systems made by Siemens and is programmed to steal data from them. Microsoft has issued an emergency patch for the Windows Shortcut hole and Siemens offers advice at http://support.automation.siemens.com/WW/view/en/43876783 Source: cnet news http://news.cnet.com/8301-27080_3-20013545-245.html Sensing Wind Speed with Kites Kites have a long history in meteorological research, including being used to carry aloft sensors that measure wind speed. However, because these sensors were exposed to direct sunlight they were prone to temperature errors that affected their accuracy. Now researchers have developed a way to use a kite itself to measure wind speed: a ground-based strain gauge monitors the tension in the kite's tether line. That line tension is linearly related to wind speed. Source: American Institute of Physics http://rsi.aip.org/resource/1/rsinak/v81/i7/ Warning system monitors lube oil on ships University researchers have developed a computerised early-warning system which keeps the 'lifeblood' of a ship flowing: lube oil. Until now, while ships engine rooms have become automated, with sensor systems being put in place to monitor temperature, pressure, fluid level and flow monitoring - lube oil has remained a void in the engine management system. Source: University of Sunderland http://www.sunderland.ac.uk/newsevents/news/news/index.html Comb System Detects Gas Impurities to Aid Semiconductor Manufacturing Purity of ingredients is a constant concern for the semiconductor industry, because a mere trace of contaminants can damage or ruin devices. In a step toward solving a long-standing problem in semiconductor manufacturing, scientists have used their version of a "fine-toothed comb" to detect minute traces of contaminant molecules in the arsine gas used to make a variety of photonics devices. Souce: NIST https://www.nist.gov/physlab/div848/comb_080310.cfm Handset Motion Sensor Market to Grow ARCchart are predicting that the market for accelerometers, gyroscopes, magnetometers and pressure sensors will exceed $1 billion by 2014 as they are incorporated into phone handsets. Accelerometers are expected to see the greatest device penetration, with 55% of phones containing them by 2014. Penetration in smartphones will be substantially higher - 60% of these devices are expected to have a gyroscope in five years time. Source: ARCchart http://www.arcchart.com/reports/sensors.asp ________________________________________________________ ________________________________________________________ * Copyright Windmill Software Ltd * Reprinting permitted with this notice included * For more articles see https://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 https://www.windmill.co.uk/newsletter.html and an index of articles at https://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] https://www.windmill.co.uk/ https://www.windmillsoft.com/
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