Abstract: A programmable controller is disclosed that incorporates a sequence control program adapted to input and output information to a variety of local intelligent appliances at a high velocity and a high efficiency in the field of factory automation for efficiently controlling factory production lines or the field of process automation for controlling multiple industrial processes. Provided for this purpose is an improved a change-over system associated with a 1-bit processor and an ordinary processor for executing the sequence control program. Also improved are functions for a user to particularly specify a BASIC program, software/hardware control functions for a group of I/O boards for transferring signals to receiving signals from the local appliances, and the ability to program the internally stored sequence control program.