Control system and SOE device

The invention provides a control system which can ensure constant periodic of control data while connecting with a system composed of an input and output device and an SOE device by a common communicating line. In order to solve the subject, the control system of the invention is provided with a calculation device; an input and output device for sending state signals inputted from a control object to the calculation device and for outputting control signals send from the calculation device; and an SOE device for obtaining the control signals or the state signals and recoding prescribed changes as event data. The calculation device, the input and output device and the SOE device are in connection through a common transmission path; the SOE device is provided with a communication control part which receives reading out requests from the calculation device according to a prescribed receiving periodic and sends the event data to the calculation device according to a prescribed receiving periodic for the reading o