摘要 |
The door has a door panel of one or more parts movable between open and closed positions. The drive shaft of the drive system (6,9) is connected to the door panel (2) whose distance moved is reproduced proportionately as a sequence of pulses (16) derived from rotation of a shaft in the drive system. The pulses are fed to a counter in an evaluation circuit (17,18) whose state is compared with stored values for previously entered door panel positions. When the signals coincide, the position signals are evaluated to produce control signals. A detector (11) of supply current variations in the running d.c. motor's commutator (10) produces the pulse sequence at its output. |