The application takes snapshots each time anyone access or leaves the place and logs day and time on it. By this way you'll be able to know the day and hour anyone was there.
Additionally, the program also offers the possibility to create a log of all accesses and checkouts featuring photos too. That means you can see at a glance what happened anyday in that place.
DATApark is a good security program if you want to make sure people arrive on time or not.