How to debug plotting error

Using VBA modules in a data analysis application to compute statistical results that I update to an Excel worksheet with existing plots (i.e. the plots aren't created each time but automatically update because the underlying data changes). Several plots use log scale. None of the result are negative and I've taken great pains to make sure none of the results are zero by making sure any result is at least E-17.

From time to time get the annoying dialog box with the message that "Negative or zero values cannot be plotted on log charts" but cannot for the life of me find any result that is zero or negative. Since Excel found something it didn't like, is there any way to further investigate exactly what it doesn't like? It is sort of like going to a doctor with a pain but not revealing the location of the pain.

Where are you storing the data that is attempting to update the graphs? Is it all visible?

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Originally Posted by vbfbryce

Where are you storing the data that is attempting to update the graphs? Is it all visible?

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Data is stored in worksheet cells and is visible. That's how I know nothing is negative or zero.

It is hard to say what is happening with out the ability to see the code and the spreadsheet setup, but perhaps it is due to some calculation taking place on partially revised data.

Try disabling automatic calculation prior to updating the values.

Code:

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Dim currentMode As XlCalculation
currentMode = Application.Calculation
Debug.Print ThisWorkbook.CalculationVersion

Application.Calculation = xlCalculationManual

' your code

Application.Calculation = currentMode
Application.Calculate
Debug.Print ThisWorkbook.CalculationVersion

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