Revolution counter and method for determining the number of revolutions of a shaft

A revolution counter for determining the number of revolutions of a shaft, the revolution counter comprising:

• sensors, with which position values that define an angular position of a shaft are generated;
• a determination unit that receives said position values from said sensors and generates decision signals from said position values, wherein said decision signals determine counting sectors within one revolution of said shaft;
• a counting control unit that receives said counting sectors from said determination unit, wherein said counting control unit, which as a function of a chronological order of said counting sectors operates said revolution counter in a first mode of operation or in a second mode of operation, and said counting control unit switches over to said second mode of operation, which is an energy-saving pulsed mode, if after a defined length of time no change in one of said counting sectors takes place, and switches over to said first mode of operation if a change in one of said counting sectors does take place;
• wherein said determination unit determines an uncertainty range between each pairing of said counting sectors;
• and
• said counting control unit does not take said uncertainty ranges which adjoins one of said counting sectors that has led to a switchover to said second mode of operation into account for said switchover from said second mode of operation to said first mode of operation.

A method for determining a number of revolutions of a shaft, in which sensors of a revolution counter are provided, with which position values that define an angular position of said shaft are generated and are delivered to a determination unit of said revolution counter, which from said position values generates decision signals, which determines counting sectors within one revolution of said shaft, said method comprising:

• delivering decision signals from said determination unit to a counting control unit, wherein said decision signals as a function of a logical order of said counting sectors operates said revolution counter in a first mode of operation or in a second mode of operation and generates counting signals for a counter;
• switching over, via said counting control unit, to said second mode of operation, which is an energy-saving pulsed mode, if after a defined length of time no change in one of said counting sectors is determined and switching over, via said controlling unit, to said first mode of operation if a change in one of said counting sectors is determined;
• determining, via said determination unit, between each two counting sectors, one uncertainty range, and said uncertainty ranges which adjoin a counting sector that has led to a switchover to said second mode of operation are not taken into account for said switchover from said second mode of operation to said first mode of operation.