MULTIPLE ROTATION ABSOLUTE POSITION DETECTOR

摘要

PURPOSE:To obtain a small-sized, lightweight detector at low cost by detecting the absolute quantity of rotation of an input shaft by an electric method which utilizes a backup battery. CONSTITUTION:When the input shaft 1 rotates, its quantity of rotation is detected by an absolute rotational quantity detection part 3 and its angle of rotation is detected by an absolute rotational angle detection part 3. This detection part 3 generates two electric signals i1 and i2 by a signal generation part 9 according to the quantity of rotation while a difference in timing is made by a half turn of the input shaft 1. Consequently, 1st and 2nd counting parts 10A and 10B perform counting operation according to them to find the absolute quantity of rotation of the input shaft 1. Those counting parts 10A and 10B are backed up and their contents are held completely even when a main power source is turned off. Then, the counting contents of the counting parts 10A and 10B are supplied to an output selection part 12 and counting contents whose accuracy is secured are selected and outputted according to the detection output of the detection part 2.