In the semi-automatic operating mode, the commands sent to the rackstacker such as pick and deposit orders are entered by hand in the form of coordinates via the keyboard of the OP7 control panel in the operator’s cabin. After having entered the co-ordinates and by simultaneously pushing the two hand control buttonss, the command gets executed (two-hands operating principle). After letting one or both of the buttons go, the rackstacker stops; when pushing the two buttons together again, the execution of the command is continued. The operator does not have to do anything else, the command gets executed fully automatically (including the operation of the forks). The functions and operation are described in more detail in 10 Appendix C "Operating Manual OP7 Panel".