| 摘要 |
<p>PURPOSE:To attain the transmission of data on all slave stations to a master station by securing such a constitution where a selection circuit monitors whether the communication request signal of the slave station selected as a transmission signal to be sent to a higher rank station is inactive or not within a 1st time and then excludes the reception signal including the communication request signal of the slave station out of the selection subjects for a 2nd time in case the request signal is not inactive within a 1st time. CONSTITUTION:A selector 10 selects a communication request signal pointed by a signal (a) received from a selection part 5 out of those input communication request signals and outputs the selected request signal to a monitor part 11. The part 11 stops a timer 12 in case the input communication request signal is inactive within a time t1. While the part 11 prevents the input of the communication request signal to the part 5 when the request signal is not inactive within the time t1. Furthermore, the part 11 starts a timer 13 for a 2nd time t2 at the time point when the timer 12 is set in a time-up state. Then the communication request signal is sent to the part 5 when the timer 13 is set in a time-up state. As a result, all other slave stations can send the data to a master station even in case a certain slave station has a fault.</p> |
