| 摘要 |
The present invention provides a variable channel block for a digital relay, which may change the number of input channels of an electricity amount measuring input signal. The variable channel block for a digital relay according to the present invention includes: a magnetic sensor that provides a digital output signal according to a magnetic field formed around a transfer path of an analog electricity amount detecting signal; a watch dog timer that is operated by a digital output signal outputted from the magnetic sensor and outputs an enable signal; and an analog-digital converter that forms one digital input channel to convert the analog electricity amount detecting signal into a digital electricity amount detecting signal and provide the digital electricity amount detecting signal to a central processing unit of the digital relay, when the analog-digital converter is enabled by the enable signal of the watch dog timer. In the present invention, only when an electricity amount detecting signal is inputted, an input channel that provides the electricity amount detecting signal to the central processing unit of the digital relay is formed, so that expandability of the input channel is ensured, and utilization of the input channel is efficient. |
