| 摘要 |
PURPOSE:To provide a simple device for warning that noise is superposed to a command signal by employing a method of indicating and warning that the noise level on a speed signal exceeds a prescribed value. CONSTITUTION:A speed control member 6 performs speed control of a motor 7 corresponding to the deviation between speed command and speed detection values. If the speed command signal with noise superposed thereto is inputted in a high pass filter 2, DC and low-frequency components are filtered and only high frequency components are outputted. This output is converted to an absolute value and smoothed by an absolute value smoothing circuit 3 in the next stage. Further a discrimination circuit 4 discriminates whether the smoothed output exceeds a prescribed value or not, and if it exceeds the prescribed value an indication lamp 5 is lit. In this constitution, it is easily seen that noise exceeding the prescribed value is superposed to the speed command signal. |
