A two-hand control safeguarding system is comprised of two basic elements: the hand controls and the control module which provides the logic.

Hand controls (also called start buttons or actuators) are mechanical push/palm buttons, capacitive touch switches, RF touch switches, or touch-activated photoelectric devices. In this tutorial, we will limit our discussion to photoelectric devices.

Control module (also called signal processor or control logic) provides the logic. The module monitors the start buttons and signals the machine control when the preconditions have been met.