End Of Travel Shut Off

End of travel shut off for the window motors is determined by monitoring the current draw of the motors. Each time it switches on a window motor, the door or BCU measures the window motor current for 22 milliseconds, in 2 milliseconds intervals. The maximum value measured within that time is stored as the switch-on current, which must be 5 A minimum. When the window motor current next exceeds the switch-on current minus 2 A, the door /BCU assumes the window has reached the end of its travel and, after 0.5 second, switches off the power supply to the window motor, even if a window switch is still being activated. Measuring the switch-on current for each switching operation automatically compensates for changes of load with varying ambient conditions etc. To protect the window motors from overheating if the end of travel shut off function fails, window motor activation in both directions is limited to 8 seconds.