datahub

I am hoping to setup an ISY-99i with several 2421 wireless open/close sensors and 2420M motion sensors as a security system. If I create a program to send me e-mail or SMS notification whenever the 2421 is opened and closed, is there the possibility that if the door is opened and closed quickly that the program may not detect the event? In other words, if the program polls the current status of the sensor and detects that it is closed (and therefore no notification is necessary), then someone opens and closes the door quickly, then the program loops back to detect if the door is open, it will see that the door is currently closed and will not have detected that the door was in fact opened and closed. Or is the program looping sufficiently fast such that for all practical purposes, no matter how quickly I open and close the door the program will detect it? Or is this an event driven (instead of polling) mechanism where opening the door will always trigger the notification? Thanks for any insight you can provide! Jack