-------------------------Monitor------------------------ The Newsletter for PC-Based Data Acquisition and Control Issue 53 www.windmill.co.uk December 2002 --------------------ISSN 1472-0221---------------------- Welcome to December's issue of Monitor and our complements of the season to you. We only send this newsletter to people who have subscribed - should you wish to cancel your free subscription please do so at http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill News: New Strain Measurement Package * Excel Corner: Tips on Naming Ranges * Exhibitions of Data Acquisition and Control ________________________________________________________ ________________________________________________________ Windmill News: New Strain Measurement Package ________________________________________________________ Our on-line catalogue now features a complete strain measurement system. The Windmill 751-SG package comprises a USB data acquisition and control unit, signal conditioning and our Windmill software. The USB unit provides differential inputs to monitor 16 strain gauges or voltage signals. Connect 8 USB units to 1 PC and monitor up to 128 strain gauges. The units also provide digital input and output and counting. Strain gauges need an external excitation to supply sufficient current to keep all the bridge circuits energised. The 751-SG package provides four sets of 16 screw terminals giving + and - excitation and signals for each of 16 bridges. When a bridge input is selected the Windmill software automatically monitors excitation voltage and performs the bridge calculation to produce a reading in microstrain. This eliminates errors due to changes in excitation voltage, especially important in long-term measurements. The changes in voltage due to strain are tiny: measured in microvolts. Monitoring such small signal changes can often produce jitter in the readings from noise. The 751-SG package counteracts this with an integrating analogue-to-digital converter. By averaging the signal over 50 or 60 Hz the noise is rejected. The initial unstrained bridge measurement is often much larger than the change in signal due to strain. If this initial value is not accounted for, it restricts the resolution you can obtain - i.e. the smallest signal you can measure. The Windmill software lets you zero or balance the bridge, nulling the offset of the initial voltage. So instead of measuring over a wide range, 0 to 0.5 V for example, you can choose a narrow range such as -0.01 to 0.01 V. The modular Windmill software suite offers data logging, charting, alarm indication, output control and DDE links to other applications like Excel. You can also add process mimic generators, sequence control and many other modules. The strain measurement system costs 775 UK pounds (around 1215 euros or 1225 US dollars). For more information see https://www.windmillsoft.com/daqshop/strain-measurement.html or contact [email protected] For a tutorial on measuring strain visit http://www.windmill.co.uk/strain.html ________________________________________________________ ________________________________________________________ Excel Corner: Tips on Naming Ranges ________________________________________________________ Giving a range of cells a meaningful name, rather than referring to, for example A1:C7, can make spreadsheets much easier to understand, use, edit and trouble-shoot. Naming ranges within Excel is a very simple process that allows us to change the way we read formulas. Instead of having a formula read =E1*E2 where E1 may store the formula to convert Celcius to Fahrenheit, and E2 a temperature reading in Celcius, we might use named ranges to make our formula look like =C_to_F*Temperature * Naming Ranges - The Basics ========================== To name a range in Excel is very easy, but there are a few rules to adhere to: 1. The first character of a name must be either a letter or the underscore (_) character. 2. We cannot give a cell the same name as an existing cell reference, for example B22 or R22C2. 3. Spaces are not allowed, but this can be overcome by using the underscore (_), full stop (.) or capitalising the first letter of words. 4. Names cannot exceed 255 characters. 5. If a name contains more than 253 characters, we will not be able to select it from the Name Box. 6. Names are not case sensitive (c_to_f is the same as C_to_F). 7. All named ranges are absolute by default, for example $E$1. To name a range in Excel you simply select the cell or cells to which you wish to apply a name, and click the top of your screen immediately to the left of your formula bar in what is called your Name Box. This highlights the active cell address which you can then type over. Type the name that you wish to apply and press the Enter key on your keyboard. From now on, no matter where you are in your Workbook, you will be able to click the drop arrow to the right of the Name Box and see a list of all named ranges. Click the one you require and you will be taken to that location. * Replacing Cell Addresses With Names In Existing Workbooks ========================================================= If you have already set up your workbook with a multitude of formulas referencing only cell addresses, and you decide that you should name your ranges but cannot face the task of manually going through changing all cell references, don't despair because Excel has made this extremely easy. Don't be tempted to use Excel's Edit>Replace feature this could cause all sorts of problems. Here is the correct method. 1. Select any cell on the worksheet. 2. Go to Insert>Name>Apply 3. Select the names you wish to use in place of references. 4. Click OK. If you now click back in any cell that was previously referencing a cell address, you will see that Excel has automatically replaced all cell references with named ranges. * Deleting or Modifying Named Ranges ================================== To delete or modify a Named Range, go to Insert>Name>Define or (Ctrl+F3). Once here you simply select the name you wish to delete and click Delete. If you want to modify to where the Named Range refers, simply select its name, alter accordingly in the Refers to: box at the bottom, then click Add. -- This article was adapted from the original by Ozgrid Business Applications. Ozgrid are specialists in distance online Excel and Excel VBA training, plus worldwide sellers of Excel add-ins and business software. Their website offers many more Excel tips and tricks - https://www.ozgrid.com/ For tips on using Excel with Windmill see http://www.windmill.co.uk/excel/ http://www.windmill.co.uk/excel/excel-charting.html ________________________________________________________ ________________________________________________________ Exhibitions and Conferences ________________________________________________________ Every other month we list forthcoming exhibitions and conferences related to data acquisition and control. MTECH 12-13 February NEC Birmingham UK British event dedicated to sensors, measurement and instrumentation. This year features the Sensor Engineering Forum which includes free workshops. http://www.mtec-info.co.uk/ Machine Building 12-13 February NEC Birmingham UK Exhibition for machine building, automation and design. Includes sensors, control equipment, motors, displays, keyboards, switches, enclosures and cabinets, barcode readers and electrical components. http://www.machinebuilding.co.uk/ Southern Manufacturing and Southern Electronics 19-20 February Thorpe Park Surrey UK Covers engineering design, production, plant and procurement. http://www.industry.co.uk/southern/ Electronic House Expo 26 February - 1 March Orange County Convention Center Orlando Florida USA Product demonstrations and seminars on home networking, automation, entertainment and security. http://www.ehexpo.com/ Midlands Manufacturing 19-20 March NEC Birmingham UK Latest developments and technology in subcontract assembly, automation, fabrication, packaging, labelling, materials, CAD/CAM & IT, inspection and electronic components. http://www.industry.co.uk/ Intertronic 25-28 March Paris Expo, Porte de Versailles Paris France. Focuses on design, systems integration, production, test and measurement. http://www.intertronic.com/en/ ________________________________________________________ * 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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