Communications control mode null of ru - punetsutowa -

摘要

PURPOSE:To reduce a fault recovery time by allowing a trigger station only to transmit a signal without acquiring a transmission right at a fault. CONSTITUTION:In a loop network consisting of a trigger station TS1 functioning as a master station and plural slave stations NS2-NS6, where the stations are connected in a loop shape by the 1st transmission line 7 and the 2nd transmission line 8 and the master station TS1 applies polling control, the master station transmits the control station added with the 1st end delimiter ED1 to the 1st transmission line 7, the 1st transmission line 7 is kept disconnected until the 1st end delimiter is detected on the 1st transmission line 7, the control signal added with the 2nd end delimiter ED2 is transmitted to the 2nd transmission line 8 and the 2nd transmission line 8 is kept disconnected until the 2nd end delimiter ED2 is detected on the 2nd transmission line 8. When a slave station acquires the transmission right to the 1st or 2nd transmission line, the slave station transmits a signal added with respective end delimiters.