Spreadsheet rebuttal

By Patrick Jorgensen -- Control Engineering, 11/1/2005

Editor's note: In the September 2005 issue, Chris Randles, CEO and president of Mathsoft Engineering & Education Inc., took Excel to task regarding its usefulness as an engineering tool. This month, a reader offers his views on the subject.

A spreadsheet used for design calculations will be as good as the talent of the individual programming the sheet, regardless of the shortcomings of some spreadsheet programs.

As with any software application, there is a risk in using the software if the designer does not understand how the software completes the calculations. All software results have to be independently verified for the range of data that will be input. There is no perfect software.

The reason that I and, I am sure, many other engineers program spreadsheets for their design calculations is that software available for design calculations is simply not sophisticated and customizable enough to efficiently be used by an engineer on a daily basis.

There are plenty of software packages available, and all that I have investigated work to some degree. But there is a big problem with purchasing pre-programmed software using compiled code. Inner workings of the code are hidden from the user, and there are no allowances for the user to customize the software for a particular application.

Software companies don't seem to understand that the calculations must seamlessly integrate with one or more other software packages, and must be dynamically linked to other software. The software format must be compatible with and usable to the linked software. Input sheets must be compatible with other software to allow data to be shared without requiring layout and format conversions.

Programming the Microsoft Excel spreadsheet using Visual Basic can produce some extraordinarily powerful design tools. They are all the more powerful since Visual Basic for Applications can be programmed across most mainstream software applications today. Dynamic linking of data saves many tedious and time-consuming steps.

Excel was originally written for the Apple Macintosh, and even Excel's first version had an amazing array of very complete mathematical tools, and well as an extremely well thought-out interface. These features, which make Excel so powerful, have remained virtually unchanged since the spreadsheet's inception.

Is Excel perfect? No, definitely not. However, I believe Excel to be an unprecedented design tool when customized with Visual Basic for Applications. Unfortunately, Microsoft has never publicized the power of customizing Excel, and the recent trend seems to be to merge the features of Excel into Microsoft's other applications. Luckily, there are a number of books on the market that can guide you in the right direction for customizing Excel.

An engineer must not only understand Excel, but also have an intimate knowledge of the field in which he operates. Armed with that knowledge, all benefits presented in Mr. Randles' article for using a "worksheet" rather than a "spreadsheet" could be easily applied to a spreadsheet.

One does not have to lose the power and flexibility of using a spreadsheet to gain the benefits proposed in Mr. Randles' article. One simply has to properly design the spreadsheet to encompass the suggested solutions.

Excel seems to be becoming the software of choice for many controls applications for input/output of data, as well as trending and graphing.

My preference is to program my own Excel design sheets to maximize my efficiency and, more importantly, to understand what my program's calculations are doing. Working with Excel in this manner also helps me better understand the limitations of the program as well as the computer on which the calculations run.