Only single plot appears on the XY graph

[happydarrel]

Hi,

I'm trying to get all the temperature data and plot them into XY graph. However, I just managed to get a single point on the XY graph and the x-axis does not display the time it gets the temperature value. I attached the output of my program. The timestamp and the waveform chart run properly. 

My main issue is to display all my temperature values every 3 seconds (the exact time) in  XY graph. 

I'm looking forward for your help. Thanks.