Small distance object state control/protection having remote located transmitter/receiver /control mechanism radiating object placed transponder with object state setting/removing radiated signal oscillator return

摘要

The object state identification method has an installation (1) with an electromagnetic transmitter/receiver (11) and a control unit (13). A transponder (3) at the object location detects the object state. The transponder is radiated by the transmitter (A) and returns a signal (R). The transponder has an oscillator (21,22) with a switch (23) which represents the object state (presence or absence).