Multi-functional power instrument is a multifunctional intelligent instrument with programmable measurement, display, digital communication and electric energy pulse transmission and output when independently developed. It can complete electric energy measurement, electric energy measurement, data display, acquisition and transmission. Multi-functional power instrument is widely used in substation automation, distribution automation, intelligent building, and internal electric energy measurement, management and assessment of enterprises. The measurement accuracy is 0.5 level, realizing LED field display and remote RS-485 digital interface communication, using communication protocol.