| 摘要 |
PURPOSE:To set many supervisory control items in a limited transmission band, by adopting the digital system due to a frequency counter or the like as a means which discriminates the frequency of a supervisory or control signal in a master station or a slave station. CONSTITUTION:In case that the slave station is controlled by the master station in respect to a control item c2, a control signal of a frequency fC2 is transmitted to the slave station from an oscillator 17 of the master station at intervals of a certain time, and this control signal has the frequency discriminated by a counter 19 in the slave station, and the control item C2 is decoded on a basis of the discrimination result by a control signal generator 20 to generate a control signal CC2. In respect to the resolution of the frequency discrimination of the supervisory signal or the control signal, though the resolution of several 10Hz is the practical limit in case of the conventional filter, the resolution of several Hz is obtained easily if an equivalent to the standard frequency counter is used as the counter 14 of the master station or the counter 19 of the slave station, and thus, the resolution of the frequency discrimination in the remote supervisory and controlling system due to this invention is improved considerably. |
