Control device with redundancy for fitting to a lock

A control device with redundancy for fitting to a lock having a mechanism for locking and unlocking a door, the control device being adapted to manage at least one change of state of the lock under predetermined conditions and to ensure that this state is kept current up until the next change of state, the control device comprising:

• a control system with redundancy comprising control means for controlling the mechanism and at least first and second electronic units for providing identical instructions to the control means, wherein the first electronic unit and the second electronic unit are connected in parallel to the control means;
• and
• a user interface between the control device and a user;
• wherein the first electronic unit has a first structure and a first mode of functioning and the second electronic unit has a second structure and a second mode of functioning, these two electronic units being so arranged that the first and second structures are different and that the first and second modes of functioning are different, while effecting common functions;
• and
• the control means behave functionally as an AND gate to the inputs of which are respectively applied the instructions from the first and second electronic units, when the control device is functioning in a normal situation.