| 摘要 |
PURPOSE:To speed up the transmission, when a differentiation inverting circuit in nonoperating state is disconnected from a bus line to obtain multichannel, by controlling a current path of the differentiation inverting circuit in open state to a bus driver in inactive state. CONSTITUTION:A plurality of controllers 107a-107n are connected to a bus line 101 and a bus driver 108 is connected to a line 103 of two lines 102, 103 constituting the line 101. Further, an auxiliary switching element 301 controlled at the same time with the driver 108 is provided, a differentiation inverting circuit 304 is connected to a connecting point between the element 301 and a resistor 302 connected to an internal power supply 303, and a switching means 305 is connected between the secondary winding of a current transformer 202 of the line 304 and the line 102. A current i2 of opposite polarity being a differentated value of a drive current i1 flowing to the driver 108 flows to the line 102, and the current path between the line 102 and a common potential point 111 with the means 305 through the circuit 304 is interrupted when the driver 108 is not in operation, allowing to speed up the transmission of signals for multichannel. |
