CONTROLLER

PURPOSE:To eliminate the limitation for types and numbers of I/Os and to improve the freedom degree and the expansion properties with a controller by setting the optional attaching position of a printed board mounting a control circuit corresponding to an input/output device connected to the controller and then setting the processing program of a connecting device based on the attachment position of the printed board and the information on the machine position. CONSTITUTION:The control circuits of I/Os 2a and 2b corresponding to printed boards 20A and 20B are connected to a controller 1a and also to option slots 14A and 14B. Then the I/O number information inherent to the boards 20A and 20B are outputted. A reading part 15a reads the mounting positions of both boards and the numbers of corresponding I/O 2a and 2b via a hard port sensor out of the boards 20A and 20B attached to the slots 14A and 14B and stores them into a connecting device number memory 16 in the order of interruption levels and in response to the panel attachment positions. At the same time, the I/O numbers and the interruption levels sent from a memory 16a are stored in the areas of a processing table 12b corresponding to the interruption level order.