| 摘要 |
PURPOSE:To make easy the transmission processing at coupled station, by including the number of total loops to be passed through and that of transmitted loops in the transmission frame. CONSTITUTION:The total loop number LN to be passed through and the loop number to be transmitted are included in the content of the transmission frame among a plurality of loops 40-43. The loop number LC is increased by one after the transmission of one loop is finished. Further, in transmitting data from the process controller 20 to the device 25, LN=3 and LC=1 are taken. Since the loop number of the reception frame is LN LC in stations 33, 34, transmission is made to the next loop according to the address of the secondary station on each loop respectively. Since LC=LN in the loop 42, this loop is the final loop and the station 55 returns the response frame. With this method, the transmitting processing at the coupled station is made easy and the transmission time is reduced. |
