| 摘要 |
PURPOSE:To provide time margin, by collecting data quickly by collecting predetermined data only by master stations, not transferring the data immediately when the transfer request of data exists and transferring the data at the next polling signal. CONSTITUTION:Subordinate stations 21, 22, 23 transmit the content of data TEXT to be changed such as arbitrarily determined measuring and setting values in advance to a master station 1 by each one sequentially at each polling to polling signals P1, P2, P3, P1... from the master station 1. The master station 1 generates an acknowledgement signal ACK when the data of the subordinate stations 21, 22, 23 is received. When the master station 1 desires to read out the data required especially to the specific subordinate station 21, for example, or to write, a transfer request signal or a write request signal P1 is transmitted to the subordinate station 21 for interruption and the subordinate station 21 generates the signal ACK. The slave station 21 answers back the data TEXT according to the next polling signal P1. |
