Ok guys, yes, Worksheet(1) instead of Worksheet(0) fixes it and it works as Archie describes. Adding in the code to write an array to the worksheet, I can get it to write a one-dimensional array into my worksheet with the code shown below. I'm almost all the way there!! The final step for me is to have my data source be a ControlLogix tag. In the quick start Youtube tutorial I made the link to a PLC tag name by setting a property of the panel meter I had placed on my main panel. Here, I have no visual control I'm working with so how do I reference the 400 element float array with tag name "Histogram1" that exists within my ControlLogix program in my Visual Basic code?
----------------------------------------------------------------------------------------------------------------------
Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim WB As New ClosedXML.Excel.XLWorkbook()
Dim FloatData As Double() = {1.1, 2.2, 3.3, 4.4, 5.5, 6.6, 7.7, 8.8, 9.9}
WB.AddWorksheet()
For i As Integer = 0 To FloatData.GetLength(0) - 1
WB.Worksheet(1).Cell(i + 2, 2).Value = FloatData(i)
Next
WB.SaveAs(".\HistogramExample.xlsx")
End Sub