A secure control device for processing a control signal and generating a first secure control command, said secure control device comprising: - a control input comprising at least a first connection point and a second connection point, said control input being arranged to receive the control signal, - a first protection circuit, - a first coupler comprising: - a first transmitter circuit connected in series with the first protection circuit, the assembly formed by the first transmitter circuit and the first protection circuit being connected between the first connection point and the second connection point, said first transmitter circuit being arranged to emit a second signal when the control signal is present on the control input, and - a first receiver circuit arranged to receive the second signal and to supply a third signal consisting of at least one pulse, - a first switch connected in parallel with the first emitter circuit, - a pulse generator connected to the first switch and arranged to cyclically control opening and closing of the first switch, and - a first processing circuit connected to the first receiver circuit for receiving the third signal, said first processing circuit being arranged to process the third signal and supply the first secure control command, said first secure control command being able to take at least two states: - a first secure run command (Sig4_ON), or - a first secure stop command (Sig4_OFF), the first protection circuit with a current limiting circuit to limit the current (i) flowing through that protection circuit, characterised by the first protection circuit having a current threshold detection circuit connected to the current limiting circuit to limit the current (i) flowing through the protection circuit to a predefined maximum current (I Max) when the amplitude (V sig1) of the control signal is greater than a predefined maximum voltage threshold (U Max), and that a voltage threshold detection circuit is connected in series with the first protection circuit and the first transmitter circuit to limit the current (i) flowing through said transmitter circuit to a predefined minimum intensity (I min) when the amplitude (V sig1) of the control signal is below a predefined minimum voltage threshold (U min). - a control input comprising at least a first connection point and a second connection point, said control input being arranged to receive the control signal, - a first protection circuit, - a first coupler comprising: - a first transmitter circuit connected in series with the first protection circuit, the assembly formed by the first transmitter circuit and the first protection circuit being connected between the first connection point and the second connection point, said first transmitter circuit being arranged to emit a second signal when the control signal is present on the control input, and - a first receiver circuit arranged to receive the second signal and to supply a third signal consisting of at least one pulse, - a first transmitter circuit connected in series with the first protection circuit, the assembly formed by the first transmitter circuit and the first protection circuit being connected between the first connection point and the second connection point, said first transmitter circuit being arranged to emit a second signal when the control signal is present on the control input, and - a first receiver circuit arranged to receive the second signal and to supply a third signal consisting of at least one pulse, - a first switch connected in parallel with the first emitter circuit, - a pulse generator connected to the first switch and arranged to cyclically control opening and closing of the first switch, and - a first processing circuit connected to the first receiver circuit for receiving the third signal, said first processing circuit being arranged to process the third signal and supply the first secure control command, said first secure control command being able to take at least two states: - a first secure run command (Sig4_ON), or - a first secure stop command (Sig4_OFF), - a first secure run command (Sig4_ON), or - a first secure stop command (Sig4_OFF),