# ISA Interchange

Welcome to the official blog of the International Society of Automation (ISA).

This blog covers numerous topics on industrial automation such as operations & management, continuous & batch processing, connectivity, manufacturing & machine control, and Industry 4.0.

The material and information contained on this website is for general information purposes only. ISA blog posts may be authored by ISA staff and guest authors from the automation community. Views and opinions expressed by a guest author are solely their own, and do not necessarily represent those of ISA. Posts made by guest authors have been subject to peer review.

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This blog post was authored by Mark Weisner, technical specialist at ISA.

The spreadsheet we did for the Applying Motor Controls and Drives course shows the voltage and hertz relationship. We then used the chart wizard and selected a scatter point type of chart. I then started thinking about the calibration sheet we do in other ISA courses and thought it would be fun to see if I could put in the formulas to calculate error and automatically plot them on a chart. The workbook that I designed has a sheet for 4-20 mA,1-5 Vdc, and 3-15 psi output results. Now you just have to put in your URV and LRV to get your test points,enter your as founds, and errors will be automatically calculated. Also if you put in the desired maximum error, it will tell you whether test passed or failed. To get a nice looking report, complete other information in cells and print.

One of the formulas I used for finding the difference between two numbers expressed as a percent is as follows:

=100-(MIN(D2,C2)/MAX(D2,C2))*100

I believe with a little more work and some feedback from automation professionals, this will be a great tool for both technicians and engineers. What kind of features would you add? Please feel free to express your opinions or ideas for what can be improved!