| 摘要 |
PROBLEM TO BE SOLVED: To obtain a field network system shortening the deviation of the detection time of the change point of the field device information detected by the field network system having two or more DI devices without using expensive devices. SOLUTION: A master device 101 for controlling two or more DI devices 103 and 104 receiving digital field device information and for controlling a field network 102 is connected to the field network 102. The master device 101 comprises a synchronous packet transmitting means 11 which transmits broadcast packets for synchronizing time to all the DI devices, and a DI data receiving means 12 which receives the field device information from the DI devices, detects a change point of this received field device information, and gives time. Each DI device comprises a time reset means 21 for resetting the time of its own device by receiving the broadcast packet. COPYRIGHT: (C)2008,JPO&INPIT
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