Abstract: A process for determining a speed and a device for implementing same are provided, wherein the counting device comprises a microprocessor, a programmable counting circuit comprising three counters and connected to the address/data bus of the microprocessor, a storage flip-flop circuit storing the selection addresses of the counters, each counter being associated with a register for preselection of a value for reinitialization of the counters and a common register of the counted values. A logic circuit receiving a masking signal produced by the third counter transfers, to the INTO input of the microprocessor, interruption signals.

Abstract: A microprocessor determines the zero cross-over times and direction of the phase voltages of the AC power line; a multiplexer has three parallel inputs which are respectively connected to the three phase conductors of the line and an output delivering a voltage formed by successive portions of the phase voltages; a flip-flop sensitive to the change of sign is connected to the output of the multiplexer; and EXCLUSIVE OR gate has an input connected to the output of the flip-flop and an other input to an output of the processor; and a NAND gate has an input connected to the output of the EXCLUSIVE OR gate and another input which receives a signal formed of a succession of square waves forming enabling windows.

Abstract: A process and device are provided for determining the mean value of the current delivered by a thyristor rectifier bridge fed by a multiphase AC network. Said device comprises successively an operational amplifier whose inverting input receives a signal representative of the current supplied by the bridge and is connected to its output by a capacitor, a blocking sampler and an analog-digital converter. The switch and the blocking sampler are controlled by a microprocessor so as to obtain an integration cycle and end of cycle sampling during a period zone of value (T/6), (T) being the period of the network.