Very simple Excel routine

I have an application ([login to view URL]) that send data to an Excel worksheet. The data is refreshed up to every 0.1 sec. There are up to 20 lines of data refreshed. I would like to log certain cells on another worksheet when certain criteria are met. For instance if any of the individual cells in a range such as AA5:AA25 >3.0 then I would like to log the data in say, cells A5,B5,C5 on worksheet 'Log', if AA5 had been >3.0 (I would have wanted to log cells A6,B6,C6 if AA6>3.0 etc). This routine should happen on each refresh, with the new data being added as a new ling to the bottom of the worksheet 'Log'. This should be a fairly simple routine if I have explained it correctly. I will be able to send an example worksheet to show the exact cells I need to watch and be logged. If you have any further questions, just ask.