GUI plot-breaks some times

Hello

I run the xPC with simulink and use the GUI using timer for plotting the data real time. As I want to my data plotting as flowing graph I saved 9*100 data(previous time data) in the handle of the GUI. My problem is 1. The data must be smooth and looks like sine wave but it breaks. I also tried to change the conditions for timer but it doesn't works. 2. I use the block "To workspace", but the the number of saved data are limited to 20000 columns. Is there any other idea to save my data in the workspace while running the xpC? I have to use the saved data while running the xPC.

Does anyone have good ideas to solve the problems? Anyway, I use the Matlab 2008a