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Software To Create Logarithmic Files

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xamcrx

Mechanical
May 27, 2003
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I'm looking to purchase software which will enable me to plot logarithmic scales and create and save templates for later use. Excel doesn't do the trick. I originally thought about MathCAD or Harvard Chart. Any ideas?
TIA
xAMcRx
 
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Thanks for your replies.
What I'm trying to do is plot force against speed for six different gear ranges and display them on one sheet. Each gear range overlaps and when we use Excel we find it tries to intelligently plot the graphs its own way. One or two of us have been on an Excel course and even had the tutor try it out to no avail.

xamcrx
 
I'm using Excel 2000, but as I recall all that I do works on earlier versions as well.

The only fundamental limitation I've found is that the min & max values for the axes must be powers of 10. At times I'd really like to cut an axis off at 120, and it is required to go to 1000. Other than that, I've found Excel to work rather well. It relies extensivelly on right-clicking, so if you're not sure what to do, try right-clicking an object or an area.

First I put the data in a sheet. In your case I used Speed for the first row, then the forces for gear 1 in the second row, the forces for gear 2 in the third row. I dragged the mouse over the first two rows, extending only as far in speed as the data for gear 1 extended. Then I used the Chart Wizard to create a graph. In the Chart Wizard select XY (scatter) as the plot type, with the data points connected by straight lines (unless you want smoothing), with or without markers as you choose. For gridlines I usually select major gridlines for both X & Y, but you might also want to select the minor gridlines. You can always edit this later. I usually put the resulting graph on a new sheet, but that isn't required.

Next I edit the plot to get the right look for me. I start by right-clicking on the plot area, select Format Plot Area, and set the area pattern to None, and the border pattern to whatever you want.

Then I right-click on the X axis, and select Format Axis. Under the Patterns tab, set the patterns as desired, and select the tick mark style for the major and minor tick marks. Under the Scale tab, set the minimum, maximum, and value axis crossings as you choose. The min & max must be powers of 10. The major and minor units are ignored, but must be non-zero. Put a check by the Logarithmic scale. Set the Font, Number, and Alignment values to your preferences. Repeat for the Y axis. Note that the min & max values should be selected to properly match the entire data set (all gears in your case).

Next I add the second data set. Repeat for more data sets, as required. Right click on the plot background, select Source Data... Under the Series tab, then select Add to add a new series (gear for you). Enter the name, x value range, and y value range. I also edit the first data series to put the proper name. I usually use cut & paste from the first data series to get the format of the data range for the second (& subsequent) data series. Note that the x values for each data series can be different; the resulting curves do NOT have to start and end at the same x values.

Sorry to be so long-winded. Just try different things to see how they work, and right-click everything to see what happens.

If you enable the Drawing Toolbar (under Tools | Customize) you can easily add notations to the resulting chart.

Good luck,
Bob
 
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