How to find the time at which zero crossing point happen using zero crossing vi

[laythzraiqat]

Hi  
Im trying to find the inflection point's time of a Bio-Signal by having the the 2nd derivative of it , then detecet the zero-crossing point of the derived signal 
What i need is to mark the inflection point on my Bio-Signal by the time at which the derived signal crosses the zero .

what blocks should be added 

[altenbach]

duplicate post