Machine safety monitor preventing unwanted running - has two different frequency generators at separate ends of safety current circuit controlling power relays

摘要

A safety circuit (4) that can be manually broken by strategically placed switches (2,3) connects two remote oscillators (5,7) to a safety station (10) via transfer elements (11,12). The two oscillators (5,7) generate different frequencies which are mixed and filtered at the safety station (10). The resultant frequency is used to control the action of the power relays. If a manual switch (2,3) is activated or damage occurs to the safety circuit (4) the subsequent loss of one oscillator frequency changes the resultant frequency at the safety station (10), initiating immediate removal of supply current by releasing the power relays. USE/ADVANTAGE - Safety monitoring circuit (1) controlling action of power relays supplying current to heavy industrial machinery. Guarantees immediate response to intended or emergency opening of safety circuit. High operational safety at minimal costs.