Graph with variable data length

Hello all.

I have a a graph inside an Excel sheet.
The graph displays some columns that holds numbers.

There is another program (Matlab) that writes the numbers into these columns.
I want the graph to show all of the range of the columns

The problem is that I can not predict the length of the data.
How can I configure the Excel graph to show the whole range of data?

(The Matlab can write somewhere (in some cell) the length of the data.
Can this help in some way?

Let the matlab put data in your specified cells, lets say A1:B10. In another column, say C1:D100, enter the formula
=IF(A1="",NA(),A1)
in C1 and copy down for the max number of rows you want to put as a range for the graph. And in D1 similarly enter and copy down the following formula:
=IF(B1="",NA(),D1)

Link the columns C and D to your graph.

When the columns A and B are blank, the corresponding rows in columns C and D will have #N/A which is ignored by the graph.

Mangesh