Phoenix Contact 2981428 A safety relay provides emergency stop and safety door monitoring capabilities up to SIL 3 or Cat 4 standards, offering one- or two-channel operation in either automatic or manual activation modes, featuring three N/O contacts, one N/C contact, and two N/O contacts with a dropout delay of 0.2 seconds to 300 seconds, along with a plug-in screw terminal block for easy connection options.