| 摘要 |
<p>Roller shutters (2) are operated by a control system (1) which in addition to full opening and closing at set times enables an intermediate position (14) to be taken up at any time. An impulse generator (27) connected mechanically to the shutter shaft indicates current shutter position to a position unit (15) via impulse meters (18,19) and the shutters are then moved (17) to an intermediate position after determination of sense (16).</p> |
