| abstract |
For driving a GTO thyristor (5, 7), a separate valve drive unit (3, 6) is provided which is connected via optical waveguides (2, 9) with a control-technology central processing unit (1). The drive unit (3, 6) receives coded control commands (EAC) via a forward channel (2) and sends coded check-back signals (RMC) via a reverse channel (9). The coding is carried out by superimposing periodic marking pulses (MP) on the base logic level of the signals to be transmitted. The periodic marking pulses (MP) correspond to an equidistant succession of pulses, the duration (TB) of which is shorter than their temporal separation (TA). In the case of a low base logic level, the coded signals (EAC) are identical to the succession of marking pulses (MP), and in the case of a high base logic level the coded signals (EAC) are the logical inversion of the succession of marking pulses (MP). An at least 3-concept check-back is possible: "GTO thyristor blocking and drive unit O.K." "GTO thyristor conducting and drive unit O.K." and "all other conditions". <IMAGE> |