GF77.20-P-3005GH Lamella Roof Position Measurement Function

GF77.20-P-3005GH Lamella Roof Position Measurement Function
- with CODE (417a) Lamella roof

The position measurement is performed by two integrated Hall sensors, the signals of which are entered by the analysis electronics in the right lamella roof motor (M12/3).
A magnetic wheel is provided on the motor shaft for this purpose and the Hall sensors, offset by 90�, react to its magnetic field by generating one pulse per revolution. The two pulse strings which are produced as a result are time-offset to each other. The analysis electronics is able to detect the direction of rotation of the motor from this offset. The momentary position of the lamella roof is derived from the number of Hall pulses.

The Hall pulses are counted positive if the lamella roof is opened, and counted negative if it is closed.

The "lamella roof closed" position is defined as the zero position, in other words if the lamella roof is fully closed, the position counter should be at zero.
The zero position is set by normalizing. In the normalized state, the analysis electronics constantly compare the current counter status with the stored values (end positions) when the lamella roof is moved. If one of the two end positions is reached, it switches off the motors (pre-block off).