| 摘要 |
PURPOSE:To prevent system-down by transmitting a reset signal to a slave station and allowing the slave station to apply data transfer again when no data is transferred from the slave station within a prescribed time after a confirming signal is transmitted to a master station. CONSTITUTION:When a start signal from a slave station 11 is detected by the closing of a contact ax, a microprocessor 203 closes a contact bx and returns the confirming signal formed by switching intermittently a contact Ps to the slave station 11 and starts a programmable timer 215. When the slave station 11 receives the confirming signal, alarm information is transferred to the master station 2. On the other hand, if the transmission/reception of the confirming signal between the master stations 2, 3 and the station 11 is not normal, since the processor 203 does not receive data transfer even after a prescribed time is elapsed after the confirming signal is transmitted, a contact rst is closed to transmit a reset signal to the slave station 11, the microprocessor 103 is reset in the slave station 11 by this signal and the program is repeated from the first. |
