POWER MONITOR AND CONTROLLER

PURPOSE:To provide a power monitor and controller which makes a low power consumption and a long life of a wiring system available by using an effective value as a measurement value of measurement information and by transmitting the measurement information to a central monitor and controller which is constituted of a personal computer, etc., using a standard transmission protocol. CONSTITUTION:An analog interface circuit 24 of a power monitoring and controlling unit 10 takes in analog signal information of a zero-phase current transformer 4, a transformer 5, and a current transformer 7 and does effective value conversion and digital conversion of an analog signal. A central processing unit (CPU) 28 generally controls the power monitoring and controlling unit 10 and does computation such as computation of power based on information about voltage and current. An operating section 18 selects information to be displayed out of information processed by the CPU 28 and a displaying section 17 displays the information selected by the operating section 18. Then, a transmission interface 16 receives a transmission signal from the CPU 16 and converts it according to RS-485 so that the converted signal can be sent through a transmission line 13 to a central monitor and controller.