| 摘要 |
PURPOSE:To prevent the entire devices from being stopped by using other slave device as a master device when the master device is stopped and the absence of polling request is detected. CONSTITUTION:A polling request is outputted from a device No.1 normally and devices NO.2-NO.n receive the polling request to the own device and output the data of the own device. If the master device NO.1 is stopped and no polling request signal exists, the device NO.2 having the shortest supervisory time becomes the master device and transmits the polling request signal. Thus, it is prevented that the entire system is stopped. |
