You might have facing any of the following issues,
- Check that you are not running into the following Known Issues:
- Open PI DataLink settings and make sure that the Number format and Time format match a format recognized by Excel. Any valid Excel format code can be used.
Check the below KB article, It will help you to resolve your issue.
I believe this is an Excel issue with the length of the array formula used to produce the results of your DataLink query. Excel array formulas have a maximum length of 255 characters as far as I know. It looks like you have embedded the filter expression into the DataLink formula (by typing it directly into the filter expression field in the PICompDat function sidebar. If this is the case, I would suggest that you place the filter expression in a cell on the spreadsheet and then reference the cell address in the DataLink function for your filter expresssion and see if that resolves the issue.
I've seen this 255 characters problem in expression reference, but I did not think to put expression in separate cell.
It works now.