Bulletin 1753 GuardPLC™ Safety I/O provides the benefits of traditional distributed I/O for Allen-Bradley® GuardPLC systems. Built-in GuardPLC 100 Mbps Ethernet network connectivity provides one of the fastest safety networks and machine stop times in the industry. The GuardPLC digital and analog I/O blocks are TÜV-certified up to SIL 3, Cat. 4, PLe.