| 摘要 |
PROBLEM TO BE SOLVED: To surely send/receive wireless information between a master station and a slave station. SOLUTION: In the operation management control system, a master station P and each of slave stations 1-m are respectively provided with an information processing section, a transmission processing section and a transmitter-receiver section. Information is sent/received between the master station and the slave stations wireleassly around the master station by means of the polling system. The transmitter-receiver section of the master station P employs two systems, the 1st system transmitter-receiver section P12-1 uses a 1st PN code PN 1 to conduct modulation/demodulation and the 2nd system transmitter-receiver section P12-2 uses a 2nd PN code PN 2 to conduct modulation/demodulation. A transmission processing section of the slave station is provided with function that receives a succeeding PN code setting command included in the received data and that send the command as a reply to a polling and that outputs the PN code setting command. The transmitter-receiver section of the slave station is provided with a circuit that receives the PN code setting command to select a PN code PN2 or PN1. Thus, either of the two kinds of PN codes PN1, PN2 is selected during a series of polling processing by the 1st and 2nd systems so as to avoid disturbance from other systems. Thus, the system is not stopped by a fault in either of the 1st and 2nd systems. |
