| 摘要 |
PURPOSE:To reduce the data collection time by recognizing a preceding or succeeding station address as a poll signal addressed to the own equipment and sending a signal taking the own station address as an address part when the station address is received in collecting information of slave station equipments is collected in the order of station address. CONSTITUTION:A master station data transmitter M and N sets of slave station data transmitters S1-SM connected to the equipment M in multi-drop form constitute a polling data transmission system. When the equipment M collects information from all transmitters Sk in the order of station address from small station address K to larger address, the master station M sends a poll signal P1 whose address part is logic 1, and the slave station S1 receiving it sends information I1 whose address part is logic 1. The signal I1 is received by the slave station S2 as well as the master station M, and the slave station S2 identifies it as the poll signal addressed to the own station and information I2 whose address part is taken as 2 is sent. Similarly, the signal I2 is identified by the slave station S3 to send information I3. Thus, the data collection time is reduced.
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