Hope this helps.
A colored bar chart indicates sample data received in the last interval/ minute
• Gray outline bars indicate statistics only data received in the last interval/minute • I
if no bar chart appears, no sample or statistics data was received
Page 342 Admin guide link :- http://h20628.www2.hp.com/km-ext/kmcsdirect/emr_na-c02566377-2.pdf
Also you might want to look at IMC now since PCM is end of sale and end of support.
IMC has a 60 day trail version incase you are interested,