------------------------Monitor------------------------- The Newsletter for PC-Based Data Acquisition and Control Issue 34 www.windmill.co.uk May 2001 --------------------ISSN 1472-0221---------------------- Thank you for subscribing to Monitor. This month we're focusing on charting and Excel. We only send this newsletter to people who have subscribed - should you wish to cancel your free subscription please visit http://www.windmill.co.uk/newsletter.html CONTENTS ======== * Windmill News: New Guide to using Windmill with Excel * Windmill Charting Tips * Excel Corner: Charting with Excel ________________________________________________________ Windmill News: New Guide to using Windmill with Excel ________________________________________________________ Learn about the ways to get real-world data into Excel. From simply importing previously logged data, to fully automated collection and analysis in Excel. http://www.windmill.co.uk/excel/ ________________________________________________________ Windmill Charting Tips ________________________________________________________ If you've downloaded the free Windmill Software suite you'll have seen our Chart program. Here are a couple of tips on using Windmill Chart. Incorporating the Chart in your Report Whilst Chart is the active window, press the Alt and Print Screen keys. This copies the Chart image to the clipboard. Now simply paste the picture of Chart into your Word, Excel or other Windows-based report. This is also useful when printing the Chart, as you can annotate the image as necessary. Showing Data Over a Longer Time-Scale To show data over a longer time-scale, and thus display more data, just change the "paper speed". For example, if the Chart window is 5 cm wide and your paper speed is 5 cm per second, you will see 5 seconds of data. If your paper speed is 5 cm per minute, you will instead see 5 minutes of data. For more details on Windmill Chart see http://www.windmill.co.uk/chart.html ________________________________________________________ Excel Corner: Charting with Excel ________________________________________________________ Spreadsheets are very useful tools for analysing your data. You can average readings over time or number of sampling points, or put data directly into reports. You can collect data with the free Windmill Logger program and after collection has finished import it into your spreadsheet. Alternatively you can transfer data as it arrives, using dynamic data exchange. For details of how to do this see http://www.windmill.co.uk/excel/ Although this article concentrates on Excel, many of the comments here also apply to other spreadsheet programs. This Excel Corner looks at charting with Excel. But first, do you need to use Excel to chart your data? It may be that Windmill's free, real-time charting program is all that is necessary. Or, for re-running charts after collection has finished, you could use the Windmill Replay software. This lets you rewind, fast- forward, zoom in, zoom out and scroll through large data files looking for areas of interest. (More details on Windmill Replay are at http://www.windmill.co.uk/replay.html) A third Windmill program, Windmill Graphics, lets you display a bar chart of the current data: a continuously changing snapshot of the live situation. So why use Excel to chart data? 1. Windmill Chart and Replay always plot data against time. With Excel you could plot, for example, temperature against depth. 2. Excel offers many different styles of chart - you may decide a stock chart, say, suits your purpose better than the Windmill charts. * Choosing the Type of Excel Chart to Use Excel provides a multitude of chart styles and it can sometimes be confusing which one is the best to use. Here we highlight three well suited to data acquisition - stock, bar & column and xy scatter. Stock Chart: Useful for Displaying High, Low and Average Readings A stock chart shows high, low and close data. This is designed for plotting stock market movements, but can be useful when plotting, say, daily temperatures. To plot the temperature range for each day you would have the date in the first column, the highest temperature of the day in the next column, the lowest temperature in the third column, and, for example, the average temperature of the day in the fourth column - replacing the stock market close data. Column and Bar: Good for Displaying Counts Column and bar charts are useful for comparison of discrete measurements made at regular intervals. For example, if you were counting people entering a building, you might use a column chart to show count totals for a series of days or weeks. To display data from several buildings you could use a stacked column chart, where figures for each building are shown as a part of the total column count. A column chart has time on the horizontal x-axis and a bar chart time on the vertical y-axis. If you have too many columns, Excel won't display all the column labels. Displaying data in bars removes this problem. Line Charts Versus xy Scatter You would usually use an xy scatter chart in preference to a line chart. With xy scatter an independent variable is plotted on the x-axis and variables dependent upon this plotted on the y-axis. When you add a trend line, you can see the relationship between the variables. For example you might see a linear relationship between the concentration of a compound in solution and its absorbance of light. With Line charts the x values are more like labels than values. They are spaced equally, no matter what their value. Using our above example, suppose you plotted absorbance against the concentration of four solutions of 0, 1, 2 and 6 mM. With xy scatter the line will be straight as the 6mM point is plotted in its correct position 4 units away from the 2 mM point. With a line chart the 6mM point is plotted just 1 unit away from the 2 mM point, giving a steep rise in absorbance and thus non-linear graph. * Excel Tip of the Month: Quickly Adding New Data to an Excel Chart Suppose you have used Windmill to log rainfall and atmospheric pressure data. You import the data file into Excel and have 3 columns: Time, Rainfall and Pressure. You create a chart plotting rainfall against time. You now decide to add the pressure data to the chart: - Highlight the pressure column - Move the mouse pointer over the edge of the highlighted data, so it changes to an arrow - Click and drag the column onto the chart Rainfall and pressure are now plotted against time. This tip courtesy OzGrid Business Applications. More charting tips are available on their web site. https://www.ozgrid.com/ ________________________________________________________ * 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@example.com http://www.windmill.co.uk/ https://www.windmillsoft.com/
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