Operation without modulo (application with 1:5 gear unit)

In the example below, a multi-turn absolute value feedback is used that has 4096 revolutions and a transmission ratio of 1:5. If the maximum encoder position at 4096 revolutions is exceeded, the encoder begins to count from zero again. It is therefore no longer possible to tell from the feedback position that 4096 revolutions have already taken place. Since a gear unit with a transmission ratio of 1:5 is used in this example and since 4096 is not divisible by 5 without a remainder, the problem described below results. In practice this means that, up to 4096 revolutions, the correct application position can be calculated from the feedback position without further information. After the overwriting of the feedback overrun, this is no longer possible without knowing the overrun that has taken place. This behavior is explained below: The first switch-off point is at 12.5 motor revolutions or 2 application revolutions + 180°. The feedback provides the value correctly after switching on again. The second switch-off point is at 4103 (4096+7) motor revolutions or 820 application revolutions + 216°. Due to the overrun at 4096 revolutions, the feedback system has not taken into account the revolution in the range (a) and displays 7 motor revolutions, but only 1 application revolution + 144°; one motor revolution (72°) is missing. This problems occurs every 4096 motor revolutions and keeps growing by one motor revolution. In order to be able to determine the correct application position, the overruns or the resulting position offset must be stored on the application side. This requirement necessitates the use of the UPS mentioned at the start, so that this can be guaranteed even in the case of a power failure.

Selecting the gear unit! If a gear unit with a transmission ratio of 2x is selected, the zero points of the motor revolution and the overrun of the absolute value encoder coincide. The above behavior does not occur.