The multi-gate monitoring system consists of the HE Series non-contact safety interlock switches and multi-gate SCU-1 control unit for machine guarding, where monitoring for a guard is required and locking is not required. The switches feature fully encapsulated solid-state, single-point switching with built in, dual color, LED status indication. The switches offer a CAT 4, SIL 3 PLe safety performance level. It has 2 N/O and 1 N/C bi-directional solid state outputs.