| 摘要 |
An electronic safety device for a protection barrier comprising a transponder (2) having an identification code (lID), a transceiver device (3) for receiving a return signal (SRX) from the transponder (2), the transponder (2) being movable with respect to the transceiver (3) and adapted to be placed at an current distance (di), an electric circuit (S, S') which is switched when the distance (di) is lower or higher than a reference distance (dr) and control and switching means (4) having a master electronic circuit (5) connected to the transceiver (3) to process the return signal (SRX) and generate a first output signal (SOUT) for switching the electronic circuit (S, S'). The transceiver device (3) is adapted to process the return signal (SRX) to generate a control signal (SC) with an electric parameter (P) variable in function of the distance (di), the control signal (SC) is a periodic signal with a frequency (fC) and has a first spectrum with a middle interval (F1) centered on the frequency (fC) when the current distance (di) is lower or equal to the reference distance (dr), and a second spectrum with lateral intervals (F2, F3) shifted with respect the middle interval (F1) when the distance (di) is higher than the reference distance (dr), the parameter (P) is associated to a frequency value that comprises either into the middle interval (F1) or into one of the lateral intervals (F2, F3). |
