A distributed input/output based, distributing control system has been for an indigenously developed 500 keV electron accelerator. The monitoring and control of each subsystem is assigned to an individual micro-controller. The processors are connected on a CAN network to communicate with each other for decision-making. Each processor incorporates a user configurable program. Each processor communicates with standard peripheral input/output modules to control inputs/outputs of the subsystem. For user program configuration on chip flash memory of the processor has been reserved. The processor can be configured by entering the control flow data on a Microsoft Excel Sheet in .CSV format and transferring it to the processor using PC.Programming using the data entry in an Excel Sheet makes it easy for the user to program a processor without knowing any programming language.The use of distributed multiple processors reduces the wiring, maintenance hence reducing the downtime of the machine.Each processor is provided with a local Touch Screen as user-friendly man-machine interface.