The foot pedal FE-FS1-SU1ASDO2-U have 3 positions with a pressure point to control dangerous movements (for instance get down of a press brake ect ). It has 2 working contacts (1NO and 1NC) to drive the movement and one safety switches (2 positive opening NC contacts) to stop the movement.
Pressing the foot pedal, till the pressure point, allows the changeover of the 2 working contacts. Once the pressure point is got over, the 2 working contacts return to their first position and the positive opening safety contact is activated in order to initiate immediately the dangerous movement.
Thus a redundant information for the safety circuit is available.
A restart of the machine is only possible after releasing the foot switch.