DISTRIBUTED CONTROL SYSTEM AND COMMUNICATION CONTROL METHOD THEREFOR

In the present invention, device information is collected while real-time performance and high-speed performance of control-related normal communication are maintained. The distributed control system has: a central processing device; a central communication device 11; multiple terminal communication devices 12 each having at least one controlled device connected thereto; an information storage device 15; and a network having a tree structure comprising multiple communication paths between the central communication device and the terminal communication devices, between the terminal communication devices, and between the terminal communication devices and the information storage device. The central communication device is provided with a normal communication port. The terminal communication devices are each provided with an upstream-side communication port 120 and a downstream-side communication port 121. The information storage device is provided with a device information communication port 150. The network is provided with: a first communication path for connecting the upstream-side communication port of a terminal communication device with the downstream-side communication port of a terminal communication device and for connecting the upstream-side communication port of a terminal communication device with the normal communication port of the central communication device; and a second communication path for connecting between the downstream-side communication ports of terminal communication devices positioned at edges of the network and for connecting the downstream-side communication ports of the terminal communication devices with the device information communication port of the information storage device.