this attachment file below show the chart that i want to print everytime it is fulfilled. 
u can see, the maximum data displayed on that chart are 30 data. 
so, i need vi to print it automatically at 30, 60, 90, ... 
for your information, suppose it will took 30 second to return 30 data and 60 second to print a page of front panel with 30 data. Delay are allowed here... 
have any idea?? 
 
 
telur.