Many modules, especially logic engines, work in a cycle. One repeat is called a scan. It begins by obtaining a copy of all the points from the MatPLC core. It then evaluates all the logic or does all the calculations (depending on the module). Finally, all changed points are written back to the MatPLC core - this only happens at the end of the scan, so if the logic wrote a point several times with different values, only the last value is ever seen by any other module.