| 摘要 |
PROBLEM TO BE SOLVED: To prevent an error from being made in the detection of an origin position caused by the mechanical deviation of stroke of an origin position detecting device by always obtaining the origin position of a lighting prism(prism) from a predetermined rotating direction in the case of obtaining the origin position thereof. SOLUTION: In a setting device 4, the position of the sun at every hour and the appropriate rotational angle of the prism at that position on that day are read from stored data interlocked with a clock incorporated in the device 4. When an instruction to drive the prism 1 is given from the device 4, the prism 1 is driven. When an instruction to detect the origin position is given from the device 4, detecting operation is started and the instruction to drive the prism 1 is given by a CPU. Whether the rotating direction of the prism 1 is clockwise or not is judged in the CPU. In the case of judging that the rotating direction is clockwise, the prism 1 reaches the position of an origin switch by keeping shifting in its rotating direction, then the origin position is stored in the CPU. In the case of judging that it is counterclockwise, the rotating direction of the prism 1 is reversed after the origin switch is turned on. |
