| 摘要 |
PURPOSE:To transfer control information and display information with simple constitution by transmitting the control information according to the phase angle of an AC power line and the display information according to the direction of a current by using the same two-wire circuit. CONSTITUTION:When control information is at a normal position (main line), two inputs to the phase comparator PHC of a subordinate station B are put in phase with each other through the operation of the switches WR1 and WR2 of a master station A, and a control reaction relay WPR is energized. When it is at the opposite position (side line), on the other hand, those two inputs are out of phase and the WPR is released. When display information is transmitted through the main line, a switch S1 is closed and through the operation of a rectifying element D1, a DC current component flowing through a current direction detector KR is positive, so the output contact of the detector KR is placed at the normal position. Therefore, a master station A knows that the display information of the subordinate station B is transmitted through the main line. When the display information is transmitted through the side line, a switch S2 is closed and the output contact of the KR is placed at the opposite position. |
