| 摘要 |
PURPOSE:To improve the reliability on a device by outputting an alarm that the relay at a counterpart's end is defective unless the checking confirmation signal is returned within the predetermined period after the checking command is transmitted. CONSTITUTION:A current differential relay device 3A consists of a current differential relay 30A and an external display panel 310A. The current differential relay 30A is equipped with an input converter 301 A, a filter 302A, a sampling hold circuit (S/H) 303A, an analogue-digital conversion circuit (A/D) 304A, a central processing unit(CPU) 307A, etc. Normal checking will be performed if it is returned within the specified time by a means of detecting whether or not the checking confirmation signal from a counterpart's end is returned within a specified time. If not, the relay at the counterpart's end will be regarded as defective and an alarm is outputted to outside that the relay at the counterpart's end is defective. |
