| 摘要 |
PURPOSE:To detect a monitor signal easily in the control unit by making a current constant in the controlled device such that the current variation caused by a monitor signal is approximately constant in any part of the controlled device when the variation is sent to the control unit. CONSTITUTION:An address code signal and a control signal which are fed to the controlled device through the transmission line 1 are voltage-devided by the resisttance R2, R3 and are discriminated by the logic circuit M through the noisecut capacitor C1 and current limit resistance R5. When the reception of address code signal is within a self address time, the transistor T1 is driven by the monitor signal output X of logic circuit M, a sunk current limited by the resistance R1 flows in the transmission line 1, its current variation is detected and reproduced by the control unit. The monitor signal current can be made approximately constant independently of the location of controlled device by adding a constant-current circuit N to the transistor T1. |
