WARNING SYSTEM Russian patent published in 1994 - IPC

FIELD: technical means of guards. SUBSTANCE: device has signal wire 1 (broken when trespasser is in the zone of control). Electric circuit of the wire is controlled by means of power source 2, current transducer 3 which is made in form of resistor, device also has threshold unit 4. Outputs of unit 4 are connected with input of delay member 5 and inverter 7. Output of the inverter is connected with one input of AND gate 8 which has output connected with input of signalling unit 9. Short-pulse former 6 is brought into the device additionally which has input and output connected with output of delay member 5 and with the other input of AND gate 8. Fault operations are excluded in the device which may be caused by powerful electromagnetic disturbances, for example, lighting, commutation of power line etc. , due to selection of duration of the delay. EFFECT: improved noise immunity. 1 dwg