Hello.

I think that there are actually 2 issues in your post:

1. Why the Excel closes or crashes with the code you provided.
2. Is the code you provided actually going to do what you want, if it worked?

At the moment I have doubts about #2, and it makes no sense to go deeper into #1 without having #2 clarified first.

The RTD function is special in that its result can change dynamically. That works in a formula in a cell. If you, however, evaluate that function inside the VBA code, you end up with a static value (number, typically). Your code then assigns this value to the cell. So if the code had worked, in the best case, you would end up with cells filled with static OPC values valid at the time you ran the code.

If your intent was to end up with cells that contain dynamic data, your code should set the *formulas* inside the cells (and the formulas should contain the RTD function), and not the *values* of the cells.

Let me know if I got it wrong or if you need further help.

Best regards
 

I'd like to loop through some tags in an array in a PLC and populate an Excel Sheet with that data.  It's basically a 12 x 50 array. I could type "=RTD.....whatever" in all 600 cells, but it would be way easier if I could do it programatically.  I can't seem to crack this one.  Using a code loop, I can loop it once using variables in the RTD strings indexed by the loop count.  I can NOT get it to work if I loop more than once.  I suspect it has something to do with the asynchronous communications of the RTD function.  The following VBA code works with an index of 1 (one loop).  If index is greater than 1, Excel thinks about it a bit, shuts itself down and then reopens in recovery mode.  Any ideas?

Sub RefreshRTD()
    For Index = 1 To 1  'Change this loop upper limit to 2 and Excel crashes'
        
        topicstring1 = "nsu=CODESYSSPV3/3S/IecVarAccess ;ns=4;s=|var|Turck/ARM/WinCE TV.Application.GVL.RandomNum[" & Index & "]"
               
        ActiveSheet.Range("D" & Index).Value = Application.WorksheetFunction.RTD("opclabs.office.excel.connectivityrtdserver", "", "opcuaattribute", _
        "opc.tcp://192.168.2.201:4840/UADiscovery", topicstring1, "", "", "Value;""""")
     
    Next
End Sub