PROGRAMMABLE CONTROLLER

PURPOSE:To attain a high speed operation of a programmable controller by connecting plural I/O memories to an arithmetic execution part and a peripheral control part with switching. CONSTITUTION:The switch circuits 34 and 35 for connection buses set between the MPU 1 and 2 and the I/O memories are connected to an I/O memory switch control circuit 36 via the control signal lines A-H. One of both I/O memories 32 and 33 is connected to the bus of an MPU 1 while the other memory is connected to the bus of the MPU 2. Then the connection is switched between both memories for each scan. The MPU 1 of an arithmetic execution part performs a control operation based on a system program memory 23 and executes a user program. In this case, the data stored in the memory 32 or 33 connected to a bus is used for operation as the input data. The arithmetic result is simultaneously written into the output data area of the memory 32 or 33 and an output data memory 26. Thus a high speed operation is attained with a programmable controller.