| 摘要 |
PURPOSE:To make it possible that a slave station discriminates abnormality to control a terminal device even if it cannot be controlled by a central monitor and control equipment, by providing the slave station with an analog quantity detector and a control circuit which drives the terminal device. CONSTITUTION:The analog signal outputted from a detecting part 3 is inputted to an A/D converter 2 and a comparator 6. The comparator 6 compares this analog signal with a reference voltage E2. The voltage E2 is set to a maximum value or higher of the analog signal converted by the converter 2. When the analog signal is higher than the voltage E2, the second control signal is outputted to the output of the comparator 6. This second control signal is used if the first control signal of an output terminal based on a control command from a central monitor and control equipment 10 cannot be expected because of troubles of the equipment 10, a transmission line 20, etc. That is, as long as power is supplied to a slave station 40, the important terminal device is controlled. |
