If a sliding door has only one panel, or if it has two panels that open in opposite directions, installing an operator is fairly simple. The most compact solution is a simple cable system operated by a winch. You can extend this method if the sliding door has more than one panel opening in each direction. For example, consider a set of three panels, all of which open in one direction. The cable opens one panel first.When the first panel completely overlaps the second panel, a stop on the second panel keeps the first panel from going past it. This causes the first and second panels to move as a unit until they overlap the third panel.Then, a stop on the third panel keeps the second from going past. From that point, the three overlapping panels move together to a fully open position. The door closes in a similar manner. From the fully open position, the cable pulls the first panel toward the closed position. The first panel moves alone until its outer edge latches to the inner edge of the second panel,so the cable pulls the two panels in train. Then, the outer edge of the second panel latches to the inner edge of the third pane, and the three panels move in train until the door is fully closed. Design the installation to provide effective sealing when the door is closed. You can do this by using interlocking channels to latch each panel to the next when it closes. See Measure 6.2.2 for details.