Controller, CompactLogix, 3 Mbyte Memory, 1 Mbyte Safety, 1 - RS232 Communications Port * Discontinued *The Compact GuardLogix controller is a 1768-L4xS CompactLogix controller that provides safety control to achieve SIL 3/PLe according to ISO 13849. A major benefit of this system is that it is still one project, safety and standard together.